基于Actuator的可修改配置的线程池监控 基于Actua

基于Actuator的可修改配置的线程池监控

1.概要

之前公司因为使用线程池习惯不好，导致线程池负载负载过高。触发了拒绝策略，导致大量任务丢失。而并没有对这个情况进行监控，导致业务出现故障之后才发现抛出了拒绝异常。所以有必要对大量使用线程池的项目进行监控，并且最好能在不停机的情况下对线程池的参数进行修改，由此我们可以用线程池的hook方法去对线程池的状态进行埋点，并且通过Actuator做可视化监控，自定义Endpoint去修改线程池内部参数，实现可以动态修改线程池参数。

2.实现

1.导入Maven依赖

pom复制代码        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

2.编写ThreadPoolMonitor.java监控类

java复制代码

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Date;
import java.util.List;
import java.util.Objects;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * 继承ThreadPoolExecutor类，覆盖了shutdown(), shutdownNow(), beforeExecute() 和 afterExecute()
 * 方法来统计线程池的执行情况
 */
public class ThreadPoolMonitor extends ThreadPoolExecutor {

    private static final Logger LOGGER = LoggerFactory.getLogger(ThreadPoolMonitor.class);

    /**
     * 保存任务开始执行的时间，当任务结束时，用任务结束时间减去开始时间计算任务执行时间
     */
    private final ConcurrentHashMap<String, Date> startTimes;

    /**
     * 线程池名称，一般以业务名称命名，方便区分
     */
    private final String poolName;


    private long totalDiff;

    /**
     * 调用父类的构造方法，并初始化HashMap和线程池名称
     *
     * @param corePoolSize    线程池核心线程数
     * @param maximumPoolSize 线程池最大线程数
     * @param keepAliveTime   线程的最大空闲时间
     * @param unit            空闲时间的单位
     * @param workQueue       保存被提交任务的队列
     * @param poolName        线程池名称
     */
    public ThreadPoolMonitor(int corePoolSize, int maximumPoolSize, long keepAliveTime,
                             TimeUnit unit, BlockingQueue<Runnable> workQueue, String poolName) {
        this(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue,
                new EventThreadFactory(poolName), poolName);
    }


    /**
     * 调用父类的构造方法，并初始化HashMap和线程池名称
     *
     * @param corePoolSize    线程池核心线程数
     * @param maximumPoolSize 线程池最大线程数
     * @param keepAliveTime   线程的最大空闲时间
     * @param unit            空闲时间的单位
     * @param workQueue       保存被提交任务的队列
     * @param threadFactory   线程工厂
     * @param poolName        线程池名称
     */
    public ThreadPoolMonitor(int corePoolSize, int maximumPoolSize, long keepAliveTime,
                             TimeUnit unit, BlockingQueue<Runnable> workQueue,
                             ThreadFactory threadFactory, String poolName) {
        super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory);
        this.startTimes = new ConcurrentHashMap<>();
        this.poolName = poolName;
    }

    /**
     * 线程池延迟关闭时（等待线程池里的任务都执行完毕），统计线程池情况
     */
    @Override
    public void shutdown() {
        // 统计已执行任务、正在执行任务、未执行任务数量
        LOGGER.info("{} Going to shutdown. Executed tasks: {}, Running tasks: {}, Pending tasks: {}",
                this.poolName, this.getCompletedTaskCount(), this.getActiveCount(), this.getQueue().size());
        super.shutdown();
    }

    /**
     * 线程池立即关闭时，统计线程池情况
     */
    @Override
    public List<Runnable> shutdownNow() {
        // 统计已执行任务、正在执行任务、未执行任务数量
        LOGGER.info("{} Going to immediately shutdown. Executed tasks: {}, Running tasks: {}, Pending tasks: {}",
                this.poolName, this.getCompletedTaskCount(), this.getActiveCount(), this.getQueue().size());
        return super.shutdownNow();
    }

    /**
     * 任务执行之前，记录任务开始时间
     */
    @Override
    protected void beforeExecute(Thread t, Runnable r) {
        startTimes.put(String.valueOf(r.hashCode()), new Date());
    }

    /**
     * 任务执行之后，计算任务结束时间
     */
    @Override
    protected void afterExecute(Runnable r, Throwable t) {
        Date startDate = startTimes.remove(String.valueOf(r.hashCode()));
        Date finishDate = new Date();
        long diff = finishDate.getTime() - startDate.getTime();
        totalDiff += diff;
        // 统计任务耗时、初始线程数、核心线程数、正在执行的任务数量、
        // 已完成任务数量、任务总数、队列里缓存的任务数量、池中存在的最大线程数、
        // 最大允许的线程数、线程空闲时间、线程池是否关闭、线程池是否终止
        LOGGER.info("{}-pool-monitor: " +
                        "Duration: {} ms, PoolSize: {}, CorePoolSize: {}, Active: {}, " +
                        "Completed: {}, Task: {}, Queue: {}, LargestPoolSize: {}, " +
                        "MaximumPoolSize: {},  KeepAliveTime: {}, isShutdown: {}, isTerminated: {}",
                this.poolName,
                diff, this.getPoolSize(), this.getCorePoolSize(), this.getActiveCount(),
                this.getCompletedTaskCount(), this.getTaskCount(), this.getQueue().size(), this.getLargestPoolSize(),
                this.getMaximumPoolSize(), this.getKeepAliveTime(TimeUnit.MILLISECONDS), this.isShutdown(), this.isTerminated());
    }


    /**
     * 生成线程池所用的线程，只是改写了线程池默认的线程工厂，传入线程池名称，便于问题追踪
     */
    static class EventThreadFactory implements ThreadFactory {
        private static final AtomicInteger POOL_NUMBER = new AtomicInteger(1);
        private final ThreadGroup group;
        private final AtomicInteger threadNumber = new AtomicInteger(1);
        private final String namePrefix;

        /**
         * 初始化线程工厂
         *
         * @param poolName 线程池名称
         */
        EventThreadFactory(String poolName) {
            SecurityManager s = System.getSecurityManager();
            group = Objects.nonNull(s) ? s.getThreadGroup() : Thread.currentThread().getThreadGroup();
            namePrefix = poolName + "-pool-" + POOL_NUMBER.getAndIncrement() + "-thread-";
        }

        @Override
        public Thread newThread(Runnable r) {
            Thread t = new Thread(group, r, namePrefix + threadNumber.getAndIncrement(), 0);
            if (t.isDaemon()) {
                t.setDaemon(false);
            }
            if (t.getPriority() != Thread.NORM_PRIORITY) {
                t.setPriority(Thread.NORM_PRIORITY);
            }
            return t;
        }
    }

    public long getTotalDiff() {
        return totalDiff;
    }


}

3.实现ResizeableBlockingQueue.java可变队列

这里我们直接修改LinkedBlockingQueue的代码，把capacity去掉final，变成一个可变参数。再新增get和set方法。

java复制代码/**
 * The type Resizeable blocking queue.
 *
 * @param <E> the type parameter
 */
public class ResizeableBlockingQueue<E> extends AbstractQueue<E>
        implements BlockingQueue<E>, java.io.Serializable {
    private static final long serialVersionUID = -1232131234709194L;
    /*
     *  基于LinkedBlockingQueue 实现的一个可变队列容量的阻塞队列
     *
     * */

    /**
     * The type Node.
     *
     * @param <E> the type parameter
     */
    static class Node<E> {
        E item;

        Node<E> next;

        Node(E x) { item = x; }
    }

    private  int capacity;

    private final AtomicInteger count = new AtomicInteger();

    transient Node<E> head;

    private transient Node<E> last;

    private final ReentrantLock takeLock = new ReentrantLock();

    private final Condition notEmpty = takeLock.newCondition();

    private final ReentrantLock putLock = new ReentrantLock();

    private final Condition notFull = putLock.newCondition();


    /**
     * Gets capacity.
     *
     * @return the capacity
     */
    public int getCapacity() {
        return capacity;
    }

    /**
     * Sets capacity.
     *
     * @param capacity the capacity
     */
    public void setCapacity(int capacity) {
        this.capacity = capacity;
    }

    private void signalNotEmpty() {
        final ReentrantLock takeLock = this.takeLock;
        takeLock.lock();
        try {
            notEmpty.signal();
        } finally {
            takeLock.unlock();
        }
    }

    private void signalNotFull() {
        final ReentrantLock putLock = this.putLock;
        putLock.lock();
        try {
            notFull.signal();
        } finally {
            putLock.unlock();
        }
    }

    private void enqueue(Node<E> node) {
        // assert putLock.isHeldByCurrentThread();
        // assert last.next == null;
        last = last.next = node;
    }

    private E dequeue() {
        // assert takeLock.isHeldByCurrentThread();
        // assert head.item == null;
        Node<E> h = head;
        Node<E> first = h.next;
        h.next = h; // help GC
        head = first;
        E x = first.item;
        first.item = null;
        return x;
    }

    /**
     * Fully lock.
     */
    void fullyLock() {
        putLock.lock();
        takeLock.lock();
    }

    /**
     * Fully unlock.
     */
    void fullyUnlock() {
        takeLock.unlock();
        putLock.unlock();
    }



    /**
     * Instantiates a new Resizeable blocking queue.
     */
    public ResizeableBlockingQueue() {
        this(Integer.MAX_VALUE);
    }

    /**
     * Instantiates a new Resizeable blocking queue.
     *
     * @param capacity the capacity
     */
    public ResizeableBlockingQueue(int capacity) {
        if (capacity <= 0) {
            throw new IllegalArgumentException();
        }
        this.capacity = capacity;
        last = head = new Node<E>(null);
    }

    /**
     * Instantiates a new Resizeable blocking queue.
     *
     * @param c the c
     */
    public ResizeableBlockingQueue(Collection<? extends E> c) {
        this(Integer.MAX_VALUE);
        final ReentrantLock putLock = this.putLock;
        putLock.lock(); // Never contended, but necessary for visibility
        try {
            int n = 0;
            for (E e : c) {
                if (e == null) {
                    throw new NullPointerException();
                }
                if (n == capacity) {
                    throw new IllegalStateException("Queue full");
                }
                enqueue(new Node<E>(e));
                ++n;
            }
            count.set(n);
        } finally {
            putLock.unlock();
        }
    }

    // this doc comment is overridden to remove the reference to collections
    // greater in size than Integer.MAX_VALUE
    @Override
    public int size() {
        return count.get();
    }

    // this doc comment is a modified copy of the inherited doc comment,
    // without the reference to unlimited queues.
    @Override
    public int remainingCapacity() {
        return capacity - count.get();
    }

    @Override
    public void put(E e) throws InterruptedException {
        if (e == null) {
            throw new NullPointerException();
        }
        // Note: convention in all put/take/etc is to preset local var
        // holding count negative to indicate failure unless set.
        int c = -1;
        Node<E> node = new Node<E>(e);
        final ReentrantLock putLock = this.putLock;
        final AtomicInteger count = this.count;
        putLock.lockInterruptibly();
        try {
            /*
             * Note that count is used in wait guard even though it is
             * not protected by lock. This works because count can
             * only decrease at this point (all other puts are shut
             * out by lock), and we (or some other waiting put) are
             * signalled if it ever changes from capacity. Similarly
             * for all other uses of count in other wait guards.
             */
            while (count.get() == capacity) {
                notFull.await();
            }
            enqueue(node);
            c = count.getAndIncrement();
            if (c + 1 < capacity) {
                notFull.signal();
            }
        } finally {
            putLock.unlock();
        }
        if (c == 0) {
            signalNotEmpty();
        }
    }

    @Override
    public boolean offer(E e, long timeout, TimeUnit unit)
            throws InterruptedException {

        if (e == null) {
            throw new NullPointerException();
        }
        long nanos = unit.toNanos(timeout);
        int c = -1;
        final ReentrantLock putLock = this.putLock;
        final AtomicInteger count = this.count;
        putLock.lockInterruptibly();
        try {
            while (count.get() == capacity) {
                if (nanos <= 0) {
                    return false;
                }
                nanos = notFull.awaitNanos(nanos);
            }
            enqueue(new Node<E>(e));
            c = count.getAndIncrement();
            if (c + 1 < capacity) {
                notFull.signal();
            }
        } finally {
            putLock.unlock();
        }
        if (c == 0) {
            signalNotEmpty();
        }
        return true;
    }

    @Override
    public boolean offer(E e) {
        if (e == null) {
            throw new NullPointerException();
        }
        final AtomicInteger count = this.count;
        if (count.get() == capacity) {
            return false;
        }
        int c = -1;
        Node<E> node = new Node<E>(e);
        final ReentrantLock putLock = this.putLock;
        putLock.lock();
        try {
            if (count.get() < capacity) {
                enqueue(node);
                c = count.getAndIncrement();
                if (c + 1 < capacity) {
                    notFull.signal();
                }
            }
        } finally {
            putLock.unlock();
        }
        if (c == 0) {
            signalNotEmpty();
        }
        return c >= 0;
    }

    @Override
    public E take() throws InterruptedException {
        E x;
        int c = -1;
        final AtomicInteger count = this.count;
        final ReentrantLock takeLock = this.takeLock;
        takeLock.lockInterruptibly();
        try {
            while (count.get() == 0) {
                notEmpty.await();
            }
            x = dequeue();
            c = count.getAndDecrement();
            if (c > 1) {
                notEmpty.signal();
            }
        } finally {
            takeLock.unlock();
        }
        if (c == capacity) {
            signalNotFull();
        }
        return x;
    }

    @Override
    public E poll(long timeout, TimeUnit unit) throws InterruptedException {
        E x = null;
        int c = -1;
        long nanos = unit.toNanos(timeout);
        final AtomicInteger count = this.count;
        final ReentrantLock takeLock = this.takeLock;
        takeLock.lockInterruptibly();
        try {
            while (count.get() == 0) {
                if (nanos <= 0) {
                    return null;
                }
                nanos = notEmpty.awaitNanos(nanos);
            }
            x = dequeue();
            c = count.getAndDecrement();
            if (c > 1) {
                notEmpty.signal();
            }
        } finally {
            takeLock.unlock();
        }
        if (c == capacity) {
            signalNotFull();
        }
        return x;
    }

    @Override
    public E poll() {
        final AtomicInteger count = this.count;
        if (count.get() == 0) {
            return null;
        }
        E x = null;
        int c = -1;
        final ReentrantLock takeLock = this.takeLock;
        takeLock.lock();
        try {
            if (count.get() > 0) {
                x = dequeue();
                c = count.getAndDecrement();
                if (c > 1) {
                    notEmpty.signal();
                }
            }
        } finally {
            takeLock.unlock();
        }
        if (c == capacity) {
            signalNotFull();
        }
        return x;
    }

    @Override
    public E peek() {
        if (count.get() == 0) {
            return null;
        }
        final ReentrantLock takeLock = this.takeLock;
        takeLock.lock();
        try {
            Node<E> first = head.next;
            if (first == null) {
                return null;
            } else {
                return first.item;
            }
        } finally {
            takeLock.unlock();
        }
    }

    void unlink(Node<E> p, Node<E> trail) {
        // assert isFullyLocked();
        // p.next is not changed, to allow iterators that are
        // traversing p to maintain their weak-consistency guarantee.
        p.item = null;
        trail.next = p.next;
        if (last == p) {
            last = trail;
        }
        if (count.getAndDecrement() == capacity) {
            notFull.signal();
        }
    }

    @Override
    public boolean remove(Object o) {
        if (o == null) {
            return false;
        }
        fullyLock();
        try {
            for (Node<E> trail = head, p = trail.next;
                 p != null;
                 trail = p, p = p.next) {
                if (o.equals(p.item)) {
                    unlink(p, trail);
                    return true;
                }
            }
            return false;
        } finally {
            fullyUnlock();
        }
    }

    @Override
    public boolean contains(Object o) {
        if (o == null) {
            return false;
        }
        fullyLock();
        try {
            for (Node<E> p = head.next; p != null; p = p.next) {
                if (o.equals(p.item)) {
                    return true;
                }
            }
            return false;
        } finally {
            fullyUnlock();
        }
    }

    @Override
    public Object[] toArray() {
        fullyLock();
        try {
            int size = count.get();
            Object[] a = new Object[size];
            int k = 0;
            for (Node<E> p = head.next; p != null; p = p.next) {
                a[k++] = p.item;
            }
            return a;
        } finally {
            fullyUnlock();
        }
    }

    @Override
    @SuppressWarnings("unchecked")
    public <T> T[] toArray(T[] a) {
        fullyLock();
        try {
            int size = count.get();
            if (a.length < size) {
                a = (T[])java.lang.reflect.Array.newInstance
                        (a.getClass().getComponentType(), size);
            }

            int k = 0;
            for (Node<E> p = head.next; p != null; p = p.next) {
                a[k++] = (T)p.item;
            }
            if (a.length > k) {
                a[k] = null;
            }
            return a;
        } finally {
            fullyUnlock();
        }
    }

    @Override
    public String toString() {
        fullyLock();
        try {
            Node<E> p = head.next;
            if (p == null) {
                return "[]";
            }

            StringBuilder sb = new StringBuilder();
            sb.append('[');
            for (;;) {
                E e = p.item;
                sb.append(e == this ? "(this Collection)" : e);
                p = p.next;
                if (p == null) {
                    return sb.append(']').toString();
                }
                sb.append(',').append(' ');
            }
        } finally {
            fullyUnlock();
        }
    }

    @Override
    public void clear() {
        fullyLock();
        try {
            for (Node<E> p, h = head; (p = h.next) != null; h = p) {
                h.next = h;
                p.item = null;
            }
            head = last;
            // assert head.item == null && head.next == null;
            if (count.getAndSet(0) == capacity) {
                notFull.signal();
            }
        } finally {
            fullyUnlock();
        }
    }

    @Override
    public int drainTo(Collection<? super E> c) {
        return drainTo(c, Integer.MAX_VALUE);
    }

    @Override
    public int drainTo(Collection<? super E> c, int maxElements) {
        if (c == null) {
            throw new NullPointerException();
        }
        if (c == this) {
            throw new IllegalArgumentException();
        }
        if (maxElements <= 0) {
            return 0;
        }
        boolean signalNotFull = false;
        final ReentrantLock takeLock = this.takeLock;
        takeLock.lock();
        try {
            int n = Math.min(maxElements, count.get());
            // count.get provides visibility to first n Nodes
            Node<E> h = head;
            int i = 0;
            try {
                while (i < n) {
                    Node<E> p = h.next;
                    c.add(p.item);
                    p.item = null;
                    h.next = h;
                    h = p;
                    ++i;
                }
                return n;
            } finally {
                // Restore invariants even if c.add() threw
                if (i > 0) {
                    // assert h.item == null;
                    head = h;
                    signalNotFull = (count.getAndAdd(-i) == capacity);
                }
            }
        } finally {
            takeLock.unlock();
            if (signalNotFull) {
                signalNotFull();
            }
        }
    }

    @Override
    public Iterator<E> iterator() {
        return new Itr();
    }

    private class Itr implements Iterator<E> {
        /*
         * Basic weakly-consistent iterator.  At all times hold the next
         * item to hand out so that if hasNext() reports true, we will
         * still have it to return even if lost race with a take etc.
         */

        private Node<E> current;
        private Node<E> lastRet;
        private E currentElement;

        Itr() {
            fullyLock();
            try {
                current = head.next;
                if (current != null) {
                    currentElement = current.item;
                }
            } finally {
                fullyUnlock();
            }
        }

        @Override
        public boolean hasNext() {
            return current != null;
        }

        private Node<E> nextNode(Node<E> p) {
            for (;;) {
                Node<E> s = p.next;
                if (s == p) {
                    return head.next;
                }
                if (s == null || s.item != null) {
                    return s;
                }
                p = s;
            }
        }

        @Override
        public E next() {
            fullyLock();
            try {
                if (current == null) {
                    throw new NoSuchElementException();
                }
                E x = currentElement;
                lastRet = current;
                current = nextNode(current);
                currentElement = (current == null) ? null : current.item;
                return x;
            } finally {
                fullyUnlock();
            }
        }

        @Override
        public void remove() {
            if (lastRet == null) {
                throw new IllegalStateException();
            }
            fullyLock();
            try {
                Node<E> node = lastRet;
                lastRet = null;
                for (Node<E> trail = head, p = trail.next;
                     p != null;
                     trail = p, p = p.next) {
                    if (p == node) {
                        unlink(p, trail);
                        break;
                    }
                }
            } finally {
                fullyUnlock();
            }
        }
    }

    /**
     * The type Lbq spliterator.
     *
     * @param <E> the type parameter
     */
    static final class LBQSpliterator<E> implements Spliterator<E> {
        static final int MAX_BATCH = 1 << 25;  // max batch array size;
        final ResizeableBlockingQueue<E> queue;
        Node<E> current;    // current node; null until initialized
        int batch;          // batch size for splits
        boolean exhausted;  // true when no more nodes
        long est;           // size estimate
        LBQSpliterator(ResizeableBlockingQueue<E> queue) {
            this.queue = queue;
            this.est = queue.size();
        }

        @Override
        public long estimateSize() { return est; }

        @Override
        public Spliterator<E> trySplit() {
            Node<E> h;
            final ResizeableBlockingQueue<E> q = this.queue;
            int b = batch;
            int n = (b <= 0) ? 1 : (b >= MAX_BATCH) ? MAX_BATCH : b + 1;
            if (!exhausted &&
                    ((h = current) != null || (h = q.head.next) != null) &&
                    h.next != null) {
                Object[] a = new Object[n];
                int i = 0;
                Node<E> p = current;
                q.fullyLock();
                try {
                    if (p != null || (p = q.head.next) != null) {
                        do {
                            if ((a[i] = p.item) != null) {
                                ++i;
                            }
                        } while ((p = p.next) != null && i < n);
                    }
                } finally {
                    q.fullyUnlock();
                }
                if ((current = p) == null) {
                    est = 0L;
                    exhausted = true;
                }
                else if ((est -= i) < 0L) {
                    est = 0L;
                }
                if (i > 0) {
                    batch = i;
                    return Spliterators.spliterator
                            (a, 0, i, Spliterator.ORDERED | Spliterator.NONNULL |
                                    Spliterator.CONCURRENT);
                }
            }
            return null;
        }

        @Override
        public void forEachRemaining(Consumer<? super E> action) {
            if (action == null) {
                throw new NullPointerException();
            }
            final ResizeableBlockingQueue<E> q = this.queue;
            if (!exhausted) {
                exhausted = true;
                Node<E> p = current;
                do {
                    E e = null;
                    q.fullyLock();
                    try {
                        if (p == null) {
                            p = q.head.next;
                        }
                        while (p != null) {
                            e = p.item;
                            p = p.next;
                            if (e != null) {
                                break;
                            }
                        }
                    } finally {
                        q.fullyUnlock();
                    }
                    if (e != null) {
                        action.accept(e);
                    }
                } while (p != null);
            }
        }

        @Override
        public boolean tryAdvance(Consumer<? super E> action) {
            if (action == null) {
                throw new NullPointerException();
            }
            final ResizeableBlockingQueue<E> q = this.queue;
            if (!exhausted) {
                E e = null;
                q.fullyLock();
                try {
                    if (current == null) {
                        current = q.head.next;
                    }
                    while (current != null) {
                        e = current.item;
                        current = current.next;
                        if (e != null) {
                            break;
                        }
                    }
                } finally {
                    q.fullyUnlock();
                }
                if (current == null) {
                    exhausted = true;
                }
                if (e != null) {
                    action.accept(e);
                    return true;
                }
            }
            return false;
        }

        @Override
        public int characteristics() {
            return Spliterator.ORDERED | Spliterator.NONNULL |
                    Spliterator.CONCURRENT;
        }
    }

    public Spliterator<E> spliterator() {
        return new LBQSpliterator<E>(this);
    }

    private void writeObject(java.io.ObjectOutputStream s)
            throws java.io.IOException {

        fullyLock();
        try {
            // Write out any hidden stuff, plus capacity
            s.defaultWriteObject();

            // Write out all elements in the proper order.
            for (Node<E> p = head.next; p != null; p = p.next) {
                s.writeObject(p.item);
            }

            // Use trailing null as sentinel
            s.writeObject(null);
        } finally {
            fullyUnlock();
        }
    }

    private void readObject(java.io.ObjectInputStream s)
            throws java.io.IOException, ClassNotFoundException {
        // Read in capacity, and any hidden stuff
        s.defaultReadObject();

        count.set(0);
        last = head = new Node<E>(null);

        // Read in all elements and place in queue
        for (;;) {
            @SuppressWarnings("unchecked")
            E item = (E)s.readObject();
            if (item == null) {
                break;
            }
            add(item);
        }
    }
}

4.实现ThreadPoolUtil.java

编写线程池工具类，通过Util去创建线程池，并且用HashMap去指向创建的线程池，之后可以通过这个HashMap去获取线程池。

java复制代码/**
 * The type Thread pool util.
 * 线程池工具类
 */
@Component
public class ThreadPoolUtil {
    /**
     * 通过Hash去指向创建的线程池，之后可以通过这个HashMap去获取线程池
     */
    private final HashMap<String, ThreadPoolMonitor> threadPoolExecutorHashMap = new HashMap<>();

    /**
     * Creat thread pool thread pool monitor.
     *
     * 可以自定义队列类型的构造器
     *
     * @param corePoolSize    the core pool size
     * @param maximumPoolSize the maximum pool size
     * @param keepAliveTime   the keep alive time
     * @param unit            the unit
     * @param workQueue       the work queue
     * @param poolName        the pool name
     * @return the thread pool monitor
     */
    public ThreadPoolMonitor creatThreadPool(int corePoolSize, int maximumPoolSize, long keepAliveTime,
                                             TimeUnit unit, BlockingQueue<Runnable> workQueue, String poolName) {
        ThreadPoolMonitor threadPoolExecutor = new ThreadPoolMonitor(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, poolName);
        threadPoolExecutorHashMap.put(poolName, threadPoolExecutor);
        return threadPoolExecutor;
    }

    /**
     * Creat thread pool thread pool monitor.
     *
     * ResizeableBlockingQueue 里面修改了capacity参数
     * 可以通过set方法去修改队列的大小
     * 使用默认队列的构造器
     *
     * @param corePoolSize    the core pool size
     * @param maximumPoolSize the maximum pool size
     * @param keepAliveTime   the keep alive time
     * @param unit            the unit
     * @param queueSize       the queue size
     * @param poolName        the pool name
     * @return the thread pool monitor
     */
    public ThreadPoolMonitor creatThreadPool(int corePoolSize, int maximumPoolSize, long keepAliveTime,
                                             TimeUnit unit, int queueSize, String poolName) {
        ThreadPoolMonitor threadPoolExecutor = new ThreadPoolMonitor(corePoolSize, maximumPoolSize, keepAliveTime, unit, new ResizeableBlockingQueue<>(queueSize), poolName);
        threadPoolExecutorHashMap.put(poolName, threadPoolExecutor);
        return threadPoolExecutor;
    }

    /**
     * Gets thread pool executor hash map.
     *
     * @return the thread pool executor hash map
     */
    public HashMap<String, ThreadPoolMonitor> getThreadPoolExecutorHashMap() {
        return threadPoolExecutorHashMap;
    }
}

5.实现线程池信息的实体类

实现线程池信息的实体类用来EndPoint返回数据

ThreadPoolDetailInfo.java

java复制代码

/**
 * The type Thread pool detail info.
 */
public class ThreadPoolDetailInfo {
    private String threadPoolName;
    private Integer poolSize;
    private Integer corePoolSize;
    private Integer largestPoolSize;
    private Integer maximumPoolSize;
    private long completedTaskCount;
    private Integer active;
    private long task;
    private long keepAliveTime;
    private String activePercent;
    private Integer queueCapacity;
    private Integer queueSize;
    private long avgDiff;

    /**
     * Instantiates a new Thread pool detail info.
     *
     * @param threadPoolName     the thread pool name
     * @param poolSize           the pool size
     * @param corePoolSize       the core pool size
     * @param largestPoolSize    the largest pool size
     * @param maximumPoolSize    the maximum pool size
     * @param completedTaskCount the completed task count
     * @param active             the active
     * @param task               the task
     * @param keepAliveTime      the keep alive time
     * @param activePercent      the active percent
     * @param queueCapacity      the queue capacity
     * @param queueSize          the queue size
     * @param avgDiff            the avg diff
     */
    public ThreadPoolDetailInfo(String threadPoolName, Integer poolSize, Integer corePoolSize, Integer largestPoolSize, Integer maximumPoolSize, long completedTaskCount, Integer active, long task, long keepAliveTime, String activePercent, Integer queueCapacity, Integer queueSize, long avgDiff) {
        this.threadPoolName = threadPoolName;
        this.poolSize = poolSize;
        this.corePoolSize = corePoolSize;
        this.largestPoolSize = largestPoolSize;
        this.maximumPoolSize = maximumPoolSize;
        this.completedTaskCount = completedTaskCount;
        this.active = active;
        this.task = task;
        this.keepAliveTime = keepAliveTime;
        this.activePercent = activePercent;
        this.queueCapacity = queueCapacity;
        this.queueSize = queueSize;
        this.avgDiff = avgDiff;
    }

    /**
     * Gets thread pool name.
     *
     * @return the thread pool name
     */
    public String getThreadPoolName() {
        return threadPoolName;
    }

    /**
     * Sets thread pool name.
     *
     * @param threadPoolName the thread pool name
     */
    public void setThreadPoolName(String threadPoolName) {
        this.threadPoolName = threadPoolName;
    }

    /**
     * Gets pool size.
     *
     * @return the pool size
     */
    public Integer getPoolSize() {
        return poolSize;
    }

    /**
     * Sets pool size.
     *
     * @param poolSize the pool size
     */
    public void setPoolSize(Integer poolSize) {
        this.poolSize = poolSize;
    }

    /**
     * Gets core pool size.
     *
     * @return the core pool size
     */
    public Integer getCorePoolSize() {
        return corePoolSize;
    }

    /**
     * Sets core pool size.
     *
     * @param corePoolSize the core pool size
     */
    public void setCorePoolSize(Integer corePoolSize) {
        this.corePoolSize = corePoolSize;
    }

    /**
     * Gets largest pool size.
     *
     * @return the largest pool size
     */
    public Integer getLargestPoolSize() {
        return largestPoolSize;
    }

    /**
     * Sets largest pool size.
     *
     * @param largestPoolSize the largest pool size
     */
    public void setLargestPoolSize(Integer largestPoolSize) {
        this.largestPoolSize = largestPoolSize;
    }

    /**
     * Gets maximum pool size.
     *
     * @return the maximum pool size
     */
    public Integer getMaximumPoolSize() {
        return maximumPoolSize;
    }

    /**
     * Sets maximum pool size.
     *
     * @param maximumPoolSize the maximum pool size
     */
    public void setMaximumPoolSize(Integer maximumPoolSize) {
        this.maximumPoolSize = maximumPoolSize;
    }

    /**
     * Gets completed task count.
     *
     * @return the completed task count
     */
    public long getCompletedTaskCount() {
        return completedTaskCount;
    }

    /**
     * Sets completed task count.
     *
     * @param completedTaskCount the completed task count
     */
    public void setCompletedTaskCount(long completedTaskCount) {
        this.completedTaskCount = completedTaskCount;
    }

    /**
     * Gets active.
     *
     * @return the active
     */
    public Integer getActive() {
        return active;
    }

    /**
     * Sets active.
     *
     * @param active the active
     */
    public void setActive(Integer active) {
        this.active = active;
    }

    /**
     * Gets task.
     *
     * @return the task
     */
    public long getTask() {
        return task;
    }

    /**
     * Sets task.
     *
     * @param task the task
     */
    public void setTask(long task) {
        this.task = task;
    }

    /**
     * Gets keep alive time.
     *
     * @return the keep alive time
     */
    public long getKeepAliveTime() {
        return keepAliveTime;
    }

    /**
     * Sets keep alive time.
     *
     * @param keepAliveTime the keep alive time
     */
    public void setKeepAliveTime(long keepAliveTime) {
        this.keepAliveTime = keepAliveTime;
    }

    /**
     * Gets active percent.
     *
     * @return the active percent
     */
    public String getActivePercent() {
        return activePercent;
    }

    /**
     * Sets active percent.
     *
     * @param activePercent the active percent
     */
    public void setActivePercent(String activePercent) {
        this.activePercent = activePercent;
    }

    /**
     * Gets queue capacity.
     *
     * @return the queue capacity
     */
    public Integer getQueueCapacity() {
        return queueCapacity;
    }

    /**
     * Sets queue capacity.
     *
     * @param queueCapacity the queue capacity
     */
    public void setQueueCapacity(Integer queueCapacity) {
        this.queueCapacity = queueCapacity;
    }

    /**
     * Gets queue size.
     *
     * @return the queue size
     */
    public Integer getQueueSize() {
        return queueSize;
    }

    /**
     * Sets queue size.
     *
     * @param queueSize the queue size
     */
    public void setQueueSize(Integer queueSize) {
        this.queueSize = queueSize;
    }

    /**
     * Gets avg diff.
     *
     * @return the avg diff
     */
    public long getAvgDiff() {
        return avgDiff;
    }

    /**
     * Sets avg diff.
     *
     * @param avgDiff the avg diff
     */
    public void setAvgDiff(long avgDiff) {
        this.avgDiff = avgDiff;
    }
}

ThreadPoolInfo.java

java复制代码
/**
 * The type Thread pool info.
 */
public class ThreadPoolInfo {
    private String threadPoolName;
    private int corePoolSize;
    private int maximumPoolSize;
    private String queueType;
    private int queueCapacity;

    /**
     * Instantiates a new Thread pool info.
     *
     * @param threadPoolName  the thread pool name
     * @param corePoolSize    the core pool size
     * @param maximumPoolSize the maximum pool size
     * @param queueType       the queue type
     * @param queueCapacity   the queue capacity
     */
    public ThreadPoolInfo(String threadPoolName, int corePoolSize, int maximumPoolSize, String queueType, int queueCapacity) {
        this.threadPoolName = threadPoolName;
        this.corePoolSize = corePoolSize;
        this.maximumPoolSize = maximumPoolSize;
        this.queueType = queueType;
        this.queueCapacity = queueCapacity;
    }

    /**
     * Gets thread pool name.
     *
     * @return the thread pool name
     */
    public String getThreadPoolName() {
        return threadPoolName;
    }

    /**
     * Sets thread pool name.
     *
     * @param threadPoolName the thread pool name
     */
    public void setThreadPoolName(String threadPoolName) {
        this.threadPoolName = threadPoolName;
    }

    /**
     * Gets core pool size.
     *
     * @return the core pool size
     */
    public int getCorePoolSize() {
        return corePoolSize;
    }

    /**
     * Sets core pool size.
     *
     * @param corePoolSize the core pool size
     */
    public void setCorePoolSize(int corePoolSize) {
        this.corePoolSize = corePoolSize;
    }

    /**
     * Gets maximum pool size.
     *
     * @return the maximum pool size
     */
    public int getMaximumPoolSize() {
        return maximumPoolSize;
    }

    /**
     * Sets maximum pool size.
     *
     * @param maximumPoolSize the maximum pool size
     */
    public void setMaximumPoolSize(int maximumPoolSize) {
        this.maximumPoolSize = maximumPoolSize;
    }

    /**
     * Gets queue type.
     *
     * @return the queue type
     */
    public String getQueueType() {
        return queueType;
    }

    /**
     * Sets queue type.
     *
     * @param queueType the queue type
     */
    public void setQueueType(String queueType) {
        this.queueType = queueType;
    }

    /**
     * Gets capacity.
     *
     * @return the capacity
     */
    public int getqueueCapacity() {
        return queueCapacity;
    }

    /**
     * Sets capacity.
     *
     * @param queueCapacity the queue capacity
     */
    public void setqueueCapacity(int queueCapacity) {
        this.queueCapacity = queueCapacity;
    }
}

6.编写EndPoint

通过actuator里的@RestControllerEndpoint注解可以添加Endpoints接口。本质上是和@Endpoint，@WebEndpoint作用是一样的，都是为服务增加actuator 接口，方便管理运行中的服务。但是有一个明显的不同是，@RestControllerEndpoint只支持Http方式的访问，不支持JMX的访问。而且，端点的方法上面只支持@GetMapping，@PostMapping，@DeleteMapping，@RequestMapping等，而不支持@ReadOperation，@WriteOperation，@DeleteOperation。而且它返回的格式是：application/json。

由于我司的监控系统只支持json格式，实际上使用Metrics和Grafana去监控会更好。

java复制代码
/**
 * The type Thread pool endpoint.
 *
 * @author newrank
 */
@RestControllerEndpoint(id = "threadpool")
@Component
public class ThreadPoolEndpoint {
    @Autowired
    private ThreadPoolUtil threadPoolUtil;

    private static final ReentrantLock LOCK = new ReentrantLock();

    private static final String RESIZEABLE_BLOCKING_QUEUE = "ResizeableBlockingQueue";


    /**
     * getThreadPools
     * 获取当前所有线程池的线程名称
     */
    @GetMapping("getThreadPools")
    private List<String> getThreadPools (){
        List<String> threadPools = new ArrayList<>();
        if (!threadPoolUtil.getThreadPoolExecutorHashMap().isEmpty()){
            for (Map.Entry<String, ThreadPoolMonitor> entry : threadPoolUtil.getThreadPoolExecutorHashMap().entrySet()) {
                threadPools.add(entry.getKey());
            }
        }
        return threadPools;
    }

    /**
     * 获取线程池可变参数信息
     * @param threadPoolName
     * @return
     */
    @GetMapping("getThreadPoolFixInfo")
    private ThreadPoolInfo getThreadPoolInfo(@RequestParam String threadPoolName){
        if (threadPoolUtil.getThreadPoolExecutorHashMap().containsKey(threadPoolName)){
            ThreadPoolMonitor threadPoolExecutor = threadPoolUtil.getThreadPoolExecutorHashMap().get(threadPoolName);
            int queueCapacity = 0;
            if (RESIZEABLE_BLOCKING_QUEUE.equals(threadPoolExecutor.getQueue().getClass().getSimpleName())){
                ResizeableBlockingQueue queue = (ResizeableBlockingQueue) threadPoolExecutor.getQueue();
                queueCapacity = queue.getCapacity();
            }
            return new ThreadPoolInfo(threadPoolName,threadPoolExecutor.getCorePoolSize(),threadPoolExecutor.getMaximumPoolSize(),
                    threadPoolExecutor.getQueue().getClass().getSimpleName(),queueCapacity);
        }
        return null;
    }


    /**
     * 修改线程池配置
     * @param threadPoolInfo
     * @return
     */
    @PostMapping("setThreadPoolFixInfo")
    private Boolean setThreadPoolInfo(@RequestBody ThreadPoolInfo threadPoolInfo){
        if (threadPoolUtil.getThreadPoolExecutorHashMap().containsKey(threadPoolInfo.getThreadPoolName())){
            LOCK.lock();
            try {
                ThreadPoolMonitor threadPoolExecutor = threadPoolUtil.getThreadPoolExecutorHashMap().get(threadPoolInfo.getThreadPoolName());
                threadPoolExecutor.setMaximumPoolSize(threadPoolInfo.getMaximumPoolSize());
                threadPoolExecutor.setCorePoolSize(threadPoolInfo.getCorePoolSize());
                if (RESIZEABLE_BLOCKING_QUEUE.equals(threadPoolExecutor.getQueue().getClass().getSimpleName())){
                    ResizeableBlockingQueue queue = (ResizeableBlockingQueue) threadPoolExecutor.getQueue();
                    queue.setCapacity(threadPoolInfo.getqueueCapacity());
                }
                return true;
            }catch (Exception e){
                e.printStackTrace();
                return false;
            }
            finally {
                LOCK.unlock();
            }
        }
        return false;
    }

    /**
     * 获取线程池监控信息
     * @return
     */
    @GetMapping("getThreadPoolListInfo")
    private List<ThreadPoolDetailInfo> getThreadPoolListInfo(){
        List<ThreadPoolDetailInfo> detailInfoList = new ArrayList<>();
        if (!threadPoolUtil.getThreadPoolExecutorHashMap().isEmpty()){
            for (Map.Entry<String, ThreadPoolMonitor> entry : threadPoolUtil.getThreadPoolExecutorHashMap().entrySet()) {
                ThreadPoolDetailInfo threadPoolDetailInfo = threadPoolInfo(entry.getValue(),entry.getKey());
                detailInfoList.add(threadPoolDetailInfo);
            }
        }
        return  detailInfoList;
    }

    /**
     * 组装线程池详情
     * @param threadPool
     * @param threadPoolName
     * @return
     */
    private  ThreadPoolDetailInfo threadPoolInfo(ThreadPoolMonitor threadPool,String threadPoolName) {
        BigDecimal activeCount = new BigDecimal(threadPool.getActiveCount());
        BigDecimal maximumPoolSize = new BigDecimal(threadPool.getMaximumPoolSize());
        BigDecimal  result =activeCount.divide(maximumPoolSize, 2, BigDecimal.ROUND_HALF_UP);
        NumberFormat numberFormat = NumberFormat.getPercentInstance();
        numberFormat.setMaximumFractionDigits(2);
        int queueCapacity = 0;
        if (RESIZEABLE_BLOCKING_QUEUE.equals(threadPool.getQueue().getClass().getSimpleName())){
            ResizeableBlockingQueue queue = (ResizeableBlockingQueue) threadPool.getQueue();
            queueCapacity = queue.getCapacity();
        }
        return new ThreadPoolDetailInfo(threadPoolName,threadPool.getPoolSize(), threadPool.getCorePoolSize(),
                threadPool.getLargestPoolSize(), threadPool.getMaximumPoolSize(), threadPool.getCompletedTaskCount(),
                threadPool.getActiveCount(),threadPool.getTaskCount(),threadPool.getKeepAliveTime(TimeUnit.MILLISECONDS),
                numberFormat.format(result.doubleValue()),queueCapacity,threadPool.getQueue().size(),threadPool.getTotalDiff()/threadPool.getTaskCount());
    }


}

7.使用线程池监控

• 注解

java复制代码 @Async("asyncExecutor")  
public  void getTrendQuery(){
   //do something
}

• 直接使用

java复制代码public void test() {  
  asyncExecutor.execute(()->{  
    //do something
            }  
    );

1. 查看线程详情

ruby复制代码http://localhost/actuator/threadpool/getThreadPoolListInfo //GET请求

返回：

json复制代码	 [
        {
            "active": 0, //正在进行的任务数
            "activePercent": "0%",//线程池负载
            "completedTaskCount": 17, //完成的任务数
            "corePoolSize": 16, //核心线程数 
            "keepAliveTime": 60000,//线程存活时间
            "largestPoolSize": 16,//到达的最大线程数
            "maximumPoolSize": 32, //最大线程数
            "poolSize": 16,//当前线程数
            "queueCapacity": 500,//队列长度 ps：如果不是ResizeableBlockingQueue 队列则默认为0
            "task": 0, //任务总数
            "queueSize":0,//队列中缓存的任务数量
            "threadPoolName": "asyncExecutor" //线程池名称
        }
    ]

2. 查看线程池参数

ini复制代码http://localhost/actuator/threadpool/getThreadPoolFixInfo?threadPoolName=asyncExecutor //GET请求

参数:

名称	类型
threadPoolName	String

返回：

json复制代码		{
	        "corePoolSize": 16, //核心线程数
	        "maximumPoolSize": 32, //最大线程数
	        "queueCapacity": 500, //队列大小
	        "queueType": "ResizeableBlockingQueue", //队列类型
	        "threadPoolName": "asyncExecutor" //线程池名称
		 }

3. 修改线程池参数

ruby复制代码https://localhost/actuator/threadpool/setThreadPoolInfo  //Post请求

参数:

名称	类型	备注
threadPoolName	String
corePoolSize	int	可变
maximumPoolSize	int	可变
queueCapacity	int	可变
queueType	String	不可变

请求类型：json

返回： Boolean

以上完整代码在Github中

Github

个人博客

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作者水平有限，若有错误遗漏，请指出。

参考文章

1.Java线程池实现原理及其在美团业务中的实践

2.Java并发（六）线程池监控

本文转载自: 掘金

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