shell复制代码go get github.com/spf13/viper

yaml复制代码# settings-dev.yaml
name: "go-gin"
port: 8022
logsAddress: "./logs/"

mysql:
 name: "root"
 host: "120.XX.XX.XX"
 port: 3306
 password: "XXXXXXXX"
 dbName: "test"
 
redis:
 host: "120.XX.XX.XX"
 port: 6379

go复制代码package config

type ServerConfig struct {
   Name        string      `mapstructure:"name"`
   Port        int         `mapstructure:"port"`
   Mysqlinfo   MysqlConfig `mapstructure:"mysql"`
   RedisInfo   RedisConfig `mapstructure:"redis"`
   LogsAddress string      `mapstructure:"logsAddress"`
}

type MysqlConfig struct {
   Host string `mapstructure:"host"`
   Port int    `mapstructure:"port"`
   Name string    `mapstructure:"name"`
   Password string    `mapstructure:"password"`
   DBName string    `mapstructure:"dbName"`
}

type RedisConfig struct {
   Host string `mapstructure:"host"`
   Port int    `mapstructure:"port"`
}

go复制代码package global
import (
	"go.uber.org/zap"
	"go_gin/config"
)

var (
    Settings config.ServerConfig
)

go复制代码package initialize

import (
	"github.com/fatih/color"
	"github.com/spf13/viper"
	"go_gin/config"
	"go_gin/global"
)

func InitConfig() {
	// 实例化viper
	v := viper.New()
	//文件的路径如何设置
	v.SetConfigFile("./settings-dev.yaml")
	if err := v.ReadInConfig(); err != nil {
		panic(err)
	}
	serverConfig := config.ServerConfig{}
	//给serverConfig初始值
	if err := v.Unmarshal(&serverConfig); err != nil {
		panic(err)
	}
	// 传递给全局变量
	global.Settings = serverConfig
	color.Blue("11111111", global.Settings.LogsAddress)
}

go复制代码package main

import (
   "fmt"
   "github.com/fatih/color"
   "go.uber.org/zap"
   "go_gin/global"
   "go_gin/initialize"   
   "go_gin/utils"
)

func main() {
   //1.初始化yaml配置
      initialize.InitConfig()

      r := gin.Default()
      r.GET("/ping", func(c *gin.Context) {
   	c.JSON(200, gin.H{
   		"message": "pong",
   	})
   })
   r.Run(fmt.Sprintf(":%d", global.Settings.Port))
}

csharp复制代码[root@localhost-181117 ~]# hostname
localhost-181117
[root@localhost-181117 ~]# hostname localhost-18111716
[root@localhost-181117 ~]# bash //更改主机名时，bash重新启量临时生效

csharp复制代码[root@localhost-181117 ~]# route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.231.0   *               255.255.255.0   U     1      0        0 eth0
default         bogon           0.0.0.0         UG    0      0        0 eth0
[root@localhost-181117 ~]#

sql复制代码[root@localhost-181117 ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.231.0   0.0.0.0         255.255.255.0   U     1      0        0 eth0
0.0.0.0         192.168.231.2   0.0.0.0         UG    0      0        0 eth0

bash复制代码[root@localhost-181117 ~]# netstat -anpt | grep ":22"
tcp        0      0 0.0.0.0:22                  0.0.0.0:*                   LISTEN      1367/sshd          
tcp        0     64 192.168.231.131:22          192.168.231.1:60782         ESTABLISHED 33595/sshd          
tcp        0      0 :::22                       :::*                        LISTEN      1367/sshd

ini复制代码[root@localhost-181117 ~]# ls /etc/sysconfig/network-scripts/ifcfg-*
/etc/sysconfig/network-scripts/ifcfg-eth0
/etc/sysconfig/network-scripts/ifcfg-lo
[root@localhost-181117 ~]
[root@localhost-181117 ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.231.131
NETMASK=255.255.255.0
GATEWAY=192.168.231.1

ini复制代码[root@localhost-181117 ~]# vi /etc/sysconfig/network
NETWORKING=yes
NETWORKING=yes
HOSTNAME=localhost-181117

csharp复制代码[root@localhost-181117 ~]# vi /etc/resolv.conf
# Generated by NetworkManager
domain localdomain
search localdomain
nameserver 192.168.231.2

csharp复制代码[root@localhost-181117 ~]# cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
[root@localhost-181117 ~]#

csharp复制代码[root@localhost-181117 ~]# mount /dev/cdrom /mnt
mount: block device /dev/sr0 is write-protected, mounting read-only
[root@localhost-181117 ~]#

ruby复制代码[root@localhost-181117 ~]# cd /mnt/Packages/
[root@localhost-181117 Packages]# rpm -ivh dhcp-4.1.1-38.P1.el6.centos.x86_64.rpm
warning: dhcp-4.1.1-38.P1.el6.centos.x86_64.rpm: Header V3 RSA/SHA1 Signature, key ID c105b9de: NOKEY
Preparing...                ########################################### [100%]
  1:dhcp                   ########################################### [100%]
[root@localhost-181117 Packages]#

ini复制代码[root@localhost-181117 Packages]# cd /etc/dhcp/
[root@localhost-181117 dhcp]# ls
dhclient.d  dhcpd6.conf  dhcpd.conf
[root@localhost-181117 dhcp]# vi dhcpd.conf

#
# DHCP Server Configuration file.
#   see /usr/share/doc/dhcp*/dhcpd.conf.sample
#   see 'man 5 dhcpd.conf'
#

typescript复制代码[root@localhost-181117 dhcp]# cp /usr/share/doc/dhcp*/dhcpd.conf.sample /etc/dhcp/dhcpd.conf
cp：是否覆盖"/etc/dhcp/dhcpd.conf"？ y

ini复制代码[root@localhost-181117 dhcp]# vi dhcpd.conf

subnet 192.168.231.0 netmask 255.255.255.0 {

   range 192.168.231.128 192.168.231.254;
   option routers          192.168.231.1;
}

perl复制代码[root@localhost-181117 dhcp]# vi dhcpd.conf
host prtsvr {
  hardware ethernet 00:0C:29:75:91:EC;
  fixed-address 192.168.231.132;
}
:wq
[root@localhost-181117 dhcp]# service dhcpd restart
关闭 dhcpd：                                               [确定]
正在启动 dhcpd：                                           [确定]
[root@localhost-181117 dhcp]#

java复制代码-vmargs -Xms128M -Xmx512M -XX:PermSize=64M -XX:MaxPermSize=128M
-vmargs 说明后面是VM的参数，所以后面的其实都是JVM的参数了
-Xms128m JVM初始分配的堆内存
-Xmx512m JVM最大允许分配的堆内存，按需分配
-XX:PermSize=64M JVM初始分配的非堆内存
-XX:MaxPermSize=128M JVM最大允许分配的非堆内存，按需分配

复制代码save 900 1
save 300 10
save 60 10000

shell复制代码 go get -u github.com/gin-gonic/gin

go复制代码package main
import "github.com/gin-gonic/gin"
func main() {
	r := gin.Default()
	r.GET("/ping", func(c *gin.Context) {
		c.JSON(200, gin.H{
			"message": "pong",
		})
	})
	r.Run() // 监听并在 0.0.0.0:8080 上启动服务
}

sql复制代码-- ----------------------------
-- Table structure for mall
-- ----------------------------
DROP TABLE IF EXISTS `mall`;
CREATE TABLE `mall`  (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `categoryId` int(11) NOT NULL,
  `name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  `price` decimal(10, 2) NOT NULL,
  `type` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  `desc` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  `img` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 1 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

sql复制代码-- ------------ MYSQL8.0.17 插入百万数据
-- 获取数据库版本
SELECT VERSION();

-- ROUND( ) 四舍五入 第二个参数表示保留两位小数 ; RAND() 返回 0-1的小数
SELECT  ROUND(RAND()*1000,2) as 'test_name';

-- ---------------------------------创建生成随机字符串函数【START】------------------------------------------------------------------
-- 修改分隔符 避免被MySQL 解析
DELIMITER $$
-- 如果存在就删除
DROP FUNCTION IF EXISTS rand_str;
-- 创建函数名 rand_str  参数为返回的长度
create FUNCTION rand_str(strlen SMALLINT ) 
-- 返回值
RETURNS VARCHAR(255)

BEGIN
--  声明的字符串
    DECLARE randStr VARCHAR(255) DEFAULT 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890';
-- 声明 i 循环变量
    DECLARE i SMALLINT DEFAULT 0;
-- 声明返回变量
    DECLARE resultStr VARCHAR(255) DEFAULT '';
    WHILE i<strlen DO
        SET resultStr=CONCAT(SUBSTR(randStr,FLOOR(RAND()*LENGTH(randStr))+1,1),resultStr);
        SET i=i+1;
    END WHILE;
    RETURN resultStr;
END $$
DELIMITER ;

-- ------------------------------------创建生成随机字符串函数【END】---------------------------------------------------------------


-- 创建函数报错，可参考 # https://www.cnblogs.com/kerrycode/p/7641835.html
show variables like 'log_bin';
show variables like '%log_bin_trust_function_creators%';
set global log_bin_trust_function_creators=1;

-- 调用随机字符串函数
select rand_str(FLOOR(RAND()*20));

-- 创建存储过程  插入1 000 000 数据
DROP PROCEDURE IF EXISTS `add_mall`;

DELIMITER $$
CREATE PROCEDURE `add_mall` ( IN n INT )
BEGIN
	DECLARE	i INT UNSIGNED DEFAULT 0;
	WHILE
            i < n DO
            INSERT INTO mall ( categoryId, `name`, price, type, `desc`, `img` )
                VALUES
                ( 1, 'test', ROUND( RAND()* 1000, 2 ), rand_str ( FLOOR( RAND()* 20 )), 'test', 'test.jpg' ),
                ( 1, 'test', ROUND( RAND()* 1000, 2 ), rand_str ( FLOOR( RAND()* 20 )), 'test', 'test.jpg' ),
                ( 1, 'test', ROUND( RAND()* 1000, 2 ), rand_str ( FLOOR( RAND()* 20 )), 'test', 'test.jpg' ),
                ( 1, 'test', ROUND( RAND()* 1000, 2 ), rand_str ( FLOOR( RAND()* 20 )), 'test', 'test.jpg' ),
                ( 1, 'test', ROUND( RAND()* 1000, 2 ), rand_str ( FLOOR( RAND()* 20 )), 'test', 'test.jpg' ),
                ( 1, 'test', ROUND( RAND()* 1000, 2 ), rand_str ( FLOOR( RAND()* 20 )), 'test', 'test.jpg' ),
                ( 1, 'test', ROUND( RAND()* 1000, 2 ), rand_str ( FLOOR( RAND()* 20 )), 'test', 'test.jpg' ),
                ( 1, 'test', ROUND( RAND()* 1000, 2 ), rand_str ( FLOOR( RAND()* 20 )), 'test', 'test.jpg' ),
                ( 1, 'test', ROUND( RAND()* 1000, 2 ), rand_str ( FLOOR( RAND()* 20 )), 'test', 'test.jpg' ),
                ( 1, 'test', ROUND( RAND()* 1000, 2 ), rand_str ( FLOOR( RAND()* 20 )), 'test', 'test.jpg' );
            SET i = i + 1;
	END WHILE;
END $$
DELIMITER; 

-- 调用存储过程 100w 829.876s
CALL add_mall(100000);

-- 如果插入数据报错，可能需要调整该值大小
show VARIABLES LIKE '%max_allowd_packet%';

sql复制代码-- 查询时不使用缓存
SELECT SQL_NO_CACHE * FROM mall WHERE type ='book';

sql复制代码-- 添加索引
ALTER TABLE mall ADD INDEX idx_book(type);
-- 删除索引
DROP INDEX idx_book ON mall;

SELECT SQL_NO_CACHE * FROM mall WHERE type ='book';

sql复制代码-- 调用上面的存储过程再插入900w条数据。  这里用了两个多小时 。。  
CALL add_mall(900000);

sql复制代码-- mysql8新特性之隐藏索引
alter TABLE mall ALTER INDEX idx_book invisible;
-- 显示索引 
alter TABLE mall ALTER INDEX idx_book visible;
-- 简单测试SQL
SELECT SQL_NO_CACHE name,type,price,`desc`,img FROM mall WHERE type = 'book'

java复制代码// 普通函数
 public static void fn(T param1,R param2){
     // ······
 }

// Lambda 
XXFunction fn = (T param1,R param2) -> {
    // ······
}

java复制代码// 完整表达式 =>
public Function<Integer, Integer> function = (Integer a) -> {
    return a * a;
};
// 单行可省略大括号 =>
public Function<Integer, Integer> function1 = (Integer a) -> (a * a);

// 参数类型可推导 =>
public Function<Integer, Integer> function2 = a -> {
    return a * a;
};
// 单参数可省略小括号
public Supplier<Integer> function3 = () -> 1;

java复制代码// 非必须，若加上则编译期会提供校验
@FunctionalInterface

// 必须声明为 interface
public interface LambdaExample<T> {

    // 单个非默认/静态实现方法
    public abstract T apply();
}

java复制代码public class Entity {
    String msg = "";

    public Entity() {

    }

    public Entity getEntity() {
        return new Entity();
    }

    public static Entity getInstance() {
        return new Entity();
    }
    
}

java复制代码// 引用构造方法
LambdaExample<Entity> example = Entity::new;

// 引用静态方法
LambdaExample<Entity> example1 = Entity::getInstance;

// 指定实例的方法
Entity entity = new Entity();
LambdaExample<Entity> example2 = entity::getEntity;

java复制代码// reduce 函数
T reduce(T identity, BinaryOperator<T> accumulator);
// 其中accumulator可以看做如下动作
BinaryOperator<T> accumulator = (acc, curr) -> {
    // do some
    retuen newAcc;
}

//整个上面两个动作可以用如下代码等价替换
R acc = identity;
for ( T curr: datas){
    // apply = do some
    acc = accumulator.apply(acc,curr);
}
return acc;

java复制代码public static int sum(Collection<Integer> list) {
	return list.stream().reduce(0, (acc, curr) -> acc + curr);
}
public static void main(String[] args) {
	List<Integer> list = Arrays.asList(2,3,4,7,5);
	System.out.println(sum(list));
}

java复制代码//第一个参数初始值，第二个参数累积累积函数，第三个函数累积累积后怎么与初始值进行合并
<U> U reduce(U identity,BiFunction<U, ? super T, U> accumulator,BinaryOperator<U> combiner);

java复制代码public static <T, R> List<R> map(List<T> list, Function<T, R> mapFn) {
    // 首先声明一个映射后的返回 List
	List<R> ret = new ArrayList<>();
    // 此时的初始值可以传入 ret List，我们需要对每个元素进行操作添加到该list中
	return list.stream().reduce(ret, (acc, curr) -> {
				R newValue = mapFn.apply(curr);
				acc.add(newValue);
				return acc;
			},
			(list1, list2) -> {
				list1.addAll(list2);
				return list1;
			});
}
public static void main(String[] args) {
	List<Integer> list = Arrays.asList(2,3,4,7,5);
	List<Integer> list2 = map(list1, i->i*2);
	System.out.println(list2);
	
}

java复制代码// reduce
R acc = identity;
for ( T curr: datas){
    acc = accumulator.apply(acc,curr);
}
return acc;

// collect
R container = supplier.get();
for ( T curr: datas){
    accumulator.accept(container,curr);
}
return container;

java复制代码public class Programmer {
	private String name;
	private int level;
	private int salary;
	private int output;//from 1-10
	private String language;
}
public class Turple<L,R>{
	private final L l;
	private final R r;
	
	public Turple(L l, R r) {
		this.l = l;
		this.r = r;
	}
	@Override
	public String toString() {
		return "(" + l + ", " + r + " )";
	}
}

Java复制代码public static Map<String, Map<Integer, Turple<Integer, List<Programmer>>>> classify(List<Programmer> programmers) {
	return programmers.stream().collect(
        	// 首先把程序员语言语言分类
			Collectors.groupingBy(Programmer::getLanguage,
                    // 再这里已经通过语言分好的类后，可以继续使用groupingBy对同一语言的不同等级程序员进行分类
					Collectors.groupingBy(Programmer::getLevel,
                            // 这里collectingAndThen主要接受两个参数，一个是Collector，第二个是Collector完成后进行一个附加操作，这里就是把同一等级的程序员的工资进行一个平均
							Collectors.collectingAndThen(
									Collectors.toList(),
                                	// 此处的list就已经是同一语言同一等级的程序员list，再对该list进行求工资平均值操作
									list -> new Turple(list.stream().collect(Collectors.averagingInt(Programmer::getSalary)), list)
							)
					)
			));
}

java复制代码public 获取学生(){
	if(学校!=null){
            年级=学校.get();
            if(年级!=null){
        	班级=年级.get();
        	if（班级!=null）{
                    小组=班级.get();
                    if(小组!=null){
                	学生=小组.get();
                	return 学生
                    }
        	}
            }
	}
}

java复制代码public 获取学生(){
    return Optional.ofNullable(学校)
                    .map(学校::get)
                    .map(年级::get)
                    .map(班级::get)
                    .map(小组::get)
                    .orElse(null)
}

java复制代码@Configuration
@Data
@Slf4j
public class ApplicationConfig {

  /**
     * client host
     */
  private String host;

  /**
     * client port
     */
  private String port;

  public ApplicationConfig() {
    log.info("ApplicationConfig constructor execute");
  }

  @PostConstruct
  public void init() {
    log.info("ApplicationConfig postConstructor execute");
  }
}

java复制代码@Service
@Slf4j
public class ApplicationConfigLoadService {

  @Resource
  private ApplicationConfig applicationConfig;

  public ApplicationConfigLoadService() {
    log.info("ApplicationConfigLoadService constructor execute");
  }

  @PostConstruct
  public void load() {
    log.info("ApplicationConfigLoadService postConstruct execute");
    // 可以是从数据库，或者远程的配置中心中读取配置
    String host = "127.0.0.1";
    String port = "8080";
    applicationConfig.setHost(host);
    applicationConfig.setPort(port);
  }
}

java复制代码@Component
@Slf4j
public class ApplicationClientFactory {

  @Resource
  private ApplicationConfig applicationConfig;

  public ApplicationClientFactory() {
    log.info("ApplicationClientFactory constructor execute");
  }

  @PostConstruct
  public void init() {
    log.info("ApplicationClientFactory postConstruct execute, host:{}, port:{}",
             applicationConfig.getHost(), applicationConfig.getPort());
  }
}

properties复制代码2021-06-06 15:38:28.591  INFO 2790 --- [           main] c.y.m.c.ApplicationClientFactory         : ApplicationClientFactory constructor execute
2021-06-06 15:38:28.598  INFO 2790 --- [           main] c.y.m.configuration.ApplicationConfig    : ApplicationConfig constructor execute
2021-06-06 15:38:28.599  INFO 2790 --- [           main] c.y.m.configuration.ApplicationConfig    : ApplicationConfig postConstructor execute
2021-06-06 15:38:28.599  INFO 2790 --- [           main] c.y.m.c.ApplicationClientFactory         : ApplicationClientFactory postConstruct execute, host:null, port:null
2021-06-06 15:38:28.602  INFO 2790 --- [           main] c.y.m.c.ApplicationConfigLoadService     : ApplicationConfigLoadService constructor execute
2021-06-06 15:38:28.603  INFO 2790 --- [           main] c.y.m.c.ApplicationConfigLoadService     : ApplicationConfigLoadService postConstruct execut

java复制代码@DependsOn(value = {"applicationConfigLoadService"})
@Component
@Slf4j
public class ApplicationClientFactory

properties复制代码2021-06-06 16:36:59.944  INFO 3688 --- [           main] c.y.m.c.ApplicationConfigLoadService     : ApplicationConfigLoadService constructor execute
2021-06-06 16:36:59.948  INFO 3688 --- [           main] c.y.m.configuration.ApplicationConfig    : ApplicationConfig constructor execute
2021-06-06 16:36:59.949  INFO 3688 --- [           main] c.y.m.configuration.ApplicationConfig    : ApplicationConfig postConstructor execute
2021-06-06 16:36:59.949  INFO 3688 --- [           main] c.y.m.c.ApplicationConfigLoadService     : ApplicationConfigLoadService postConstruct execute
2021-06-06 16:36:59.950  INFO 3688 --- [           main] c.y.m.c.ApplicationClientFactory         : ApplicationClientFactory constructor execute
2021-06-06 16:36:59.951  INFO 3688 --- [           main] c.y.m.c.ApplicationClientFactory         : ApplicationClientFactory postConstruct execute, host:127.0.0.1, port:8080

java复制代码public class ApplicationClientFactory {

  @Resource
  private ApplicationConfig applicationConfig;

  // 显示依赖
  @Resource
  private ApplicationConfigLoadService applicationConfigLoadService;

  public ApplicationClientFactory() {
    log.info("ApplicationClientFactory constructor execute");
  }

  @PostConstruct
  public void init() {
    log.info("ApplicationClientFactory postConstruct execute, host:{}, port:{}",
             applicationConfig.getHost(), applicationConfig.getPort());
  }
}

properties复制代码2021-06-06 16:08:17.458  INFO 3286 --- [           main] c.y.m.c.ApplicationClientFactory         : ApplicationClientFactory constructor execute
2021-06-06 16:08:17.464  INFO 3286 --- [           main] c.y.m.configuration.ApplicationConfig    : ApplicationConfig constructor execute
2021-06-06 16:08:17.465  INFO 3286 --- [           main] c.y.m.configuration.ApplicationConfig    : ApplicationConfig postConstructor execute
2021-06-06 16:08:17.466  INFO 3286 --- [           main] c.y.m.c.ApplicationConfigLoadService     : ApplicationConfigLoadService constructor execute
2021-06-06 16:08:17.467  INFO 3286 --- [           main] c.y.m.c.ApplicationConfigLoadService     : ApplicationConfigLoadService postConstruct execute
2021-06-06 16:08:17.467  INFO 3286 --- [           main] c.y.m.c.ApplicationClientFactory         : ApplicationClientFactory postConstruct execute, host:127.0.0.1, port:8080

java复制代码public class UserInfoService {

    public UserInfo getUserInfo(Long userId) throws InterruptedException {
        Thread.sleep(300);//模拟调用耗时
        return new UserInfo("666", "捡田螺的小男孩", 27); //一般是查数据库，或者远程调用返回的
    }
}

public class MedalService {

    public MedalInfo getMedalInfo(long userId) throws InterruptedException {
        Thread.sleep(500); //模拟调用耗时
        return new MedalInfo("666", "守护勋章");
    }
}

java复制代码public class FutureTest {

    public static void main(String[] args) throws ExecutionException, InterruptedException {

        ExecutorService executorService = Executors.newFixedThreadPool(10);

        UserInfoService userInfoService = new UserInfoService();
        MedalService medalService = new MedalService();
        long userId =666L;
        long startTime = System.currentTimeMillis();

        //调用用户服务获取用户基本信息
        FutureTask<UserInfo> userInfoFutureTask = new FutureTask<>(new Callable<UserInfo>() {
            @Override
            public UserInfo call() throws Exception {
                return userInfoService.getUserInfo(userId);
            }
        });
        executorService.submit(userInfoFutureTask);

        Thread.sleep(300); //模拟主线程其它操作耗时

        FutureTask<MedalInfo> medalInfoFutureTask = new FutureTask<>(new Callable<MedalInfo>() {
            @Override
            public MedalInfo call() throws Exception {
                return medalService.getMedalInfo(userId);
            }
        });
        executorService.submit(medalInfoFutureTask);

        UserInfo userInfo = userInfoFutureTask.get();//获取个人信息结果
        MedalInfo medalInfo = medalInfoFutureTask.get();//获取勋章信息结果

        System.out.println("总共用时" + (System.currentTimeMillis() - startTime) + "ms");
    }
}

复制代码总共用时806ms

ini复制代码public class FutureTest {

    public static void main(String[] args) throws InterruptedException, ExecutionException, TimeoutException {

        UserInfoService userInfoService = new UserInfoService();
        MedalService medalService = new MedalService();
        long userId =666L;
        long startTime = System.currentTimeMillis();

        //调用用户服务获取用户基本信息
        CompletableFuture<UserInfo> completableUserInfoFuture = CompletableFuture.supplyAsync(() -> userInfoService.getUserInfo(userId));

        Thread.sleep(300); //模拟主线程其它操作耗时

        CompletableFuture<MedalInfo> completableMedalInfoFuture = CompletableFuture.supplyAsync(() -> medalService.getMedalInfo(userId)); 

        UserInfo userInfo = completableUserInfoFuture.get(2,TimeUnit.SECONDS);//获取个人信息结果
        MedalInfo medalInfo = completableMedalInfoFuture.get();//获取勋章信息结果
        System.out.println("总共用时" + (System.currentTimeMillis() - startTime) + "ms");

    }
}

swift复制代码//使用默认内置线程池ForkJoinPool.commonPool()，根据supplier构建执行任务
public static <U> CompletableFuture<U> supplyAsync(Supplier<U> supplier)
//自定义线程，根据supplier构建执行任务
public static <U> CompletableFuture<U> supplyAsync(Supplier<U> supplier, Executor executor)

java复制代码//使用默认内置线程池ForkJoinPool.commonPool()，根据runnable构建执行任务
public static CompletableFuture<Void> runAsync(Runnable runnable) 
//自定义线程，根据runnable构建执行任务
public static CompletableFuture<Void> runAsync(Runnable runnable,  Executor executor)

csharp复制代码public class FutureTest {

    public static void main(String[] args) {
        //可以自定义线程池
        ExecutorService executor = Executors.newCachedThreadPool();
        //runAsync的使用
        CompletableFuture<Void> runFuture = CompletableFuture.runAsync(() -> System.out.println("run,关注公众号:捡田螺的小男孩"), executor);
        //supplyAsync的使用
        CompletableFuture<String> supplyFuture = CompletableFuture.supplyAsync(() -> {
                    System.out.print("supply,关注公众号:捡田螺的小男孩");
                    return "捡田螺的小男孩"; }, executor);
        //runAsync的future没有返回值，输出null
        System.out.println(runFuture.join());
        //supplyAsync的future，有返回值
        System.out.println(supplyFuture.join());
        executor.shutdown(); // 线程池需要关闭
    }
}
//输出
run,关注公众号:捡田螺的小男孩
null
supply,关注公众号:捡田螺的小男孩捡田螺的小男孩

arduino复制代码public CompletableFuture<Void> thenRun(Runnable action);
public CompletableFuture<Void> thenRunAsync(Runnable action);

csharp复制代码public class FutureThenRunTest {

    public static void main(String[] args) throws ExecutionException, InterruptedException {

        CompletableFuture<String> orgFuture = CompletableFuture.supplyAsync(
                ()->{
                    System.out.println("先执行第一个CompletableFuture方法任务");
                    return "捡田螺的小男孩";
                }
        );

        CompletableFuture thenRunFuture = orgFuture.thenRun(() -> {
            System.out.println("接着执行第二个任务");
        });

        System.out.println(thenRunFuture.get());
    }
}
//输出
先执行第一个CompletableFuture方法任务
接着执行第二个任务
null

java复制代码   private static final Executor asyncPool = useCommonPool ?
        ForkJoinPool.commonPool() : new ThreadPerTaskExecutor();
        
    public CompletableFuture<Void> thenRun(Runnable action) {
        return uniRunStage(null, action);
    }

    public CompletableFuture<Void> thenRunAsync(Runnable action) {
        return uniRunStage(asyncPool, action);
    }

csharp复制代码public class FutureThenAcceptTest {

    public static void main(String[] args) throws ExecutionException, InterruptedException {

        CompletableFuture<String> orgFuture = CompletableFuture.supplyAsync(
                ()->{
                    System.out.println("原始CompletableFuture方法任务");
                    return "捡田螺的小男孩";
                }
        );

        CompletableFuture thenAcceptFuture = orgFuture.thenAccept((a) -> {
            if ("捡田螺的小男孩".equals(a)) {
                System.out.println("关注了");
            }

            System.out.println("先考虑考虑");
        });

        System.out.println(thenAcceptFuture.get());
    }
}

csharp复制代码public class FutureThenApplyTest {

    public static void main(String[] args) throws ExecutionException, InterruptedException {

        CompletableFuture<String> orgFuture = CompletableFuture.supplyAsync(
                ()->{
                    System.out.println("原始CompletableFuture方法任务");
                    return "捡田螺的小男孩";
                }
        );

        CompletableFuture<String> thenApplyFuture = orgFuture.thenApply((a) -> {
            if ("捡田螺的小男孩".equals(a)) {
                return "关注了";
            }

            return "先考虑考虑";
        });

        System.out.println(thenApplyFuture.get());
    }
}
//输出
原始CompletableFuture方法任务
关注了

php复制代码public class FutureExceptionTest {

    public static void main(String[] args) throws ExecutionException, InterruptedException {

        CompletableFuture<String> orgFuture = CompletableFuture.supplyAsync(
                ()->{
                    System.out.println("当前线程名称：" + Thread.currentThread().getName());
                    throw new RuntimeException();
                }
        );

        CompletableFuture<String> exceptionFuture = orgFuture.exceptionally((e) -> {
            e.printStackTrace();
            return "你的程序异常啦";
        });

        System.out.println(exceptionFuture.get());
    }
}
//输出
当前线程名称：ForkJoinPool.commonPool-worker-1
java.util.concurrent.CompletionException: java.lang.RuntimeException
	at java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:273)
	at java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:280)
	at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1592)
	at java.util.concurrent.CompletableFuture$AsyncSupply.exec(CompletableFuture.java:1582)
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)
Caused by: java.lang.RuntimeException
	at cn.eovie.future.FutureWhenTest.lambda$main$0(FutureWhenTest.java:13)
	at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1590)
	... 5 more
你的程序异常啦

csharp复制代码public class FutureWhenTest {

    public static void main(String[] args) throws ExecutionException, InterruptedException {

        CompletableFuture<String> orgFuture = CompletableFuture.supplyAsync(
                ()->{
                    System.out.println("当前线程名称：" + Thread.currentThread().getName());
                    try {
                        Thread.sleep(2000L);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    return "捡田螺的小男孩";
                }
        );

        CompletableFuture<String> rstFuture = orgFuture.whenComplete((a, throwable) -> {
            System.out.println("当前线程名称：" + Thread.currentThread().getName());
            System.out.println("上个任务执行完啦，还把" + a + "传过来");
            if ("捡田螺的小男孩".equals(a)) {
                System.out.println("666");
            }
            System.out.println("233333");
        });

        System.out.println(rstFuture.get());
    }
}
//输出
当前线程名称：ForkJoinPool.commonPool-worker-1
当前线程名称：ForkJoinPool.commonPool-worker-1
上个任务执行完啦，还把捡田螺的小男孩传过来
666
233333
捡田螺的小男孩

csharp复制代码public class FutureHandlerTest {

    public static void main(String[] args) throws ExecutionException, InterruptedException {

        CompletableFuture<String> orgFuture = CompletableFuture.supplyAsync(
                ()->{
                    System.out.println("当前线程名称：" + Thread.currentThread().getName());
                    try {
                        Thread.sleep(2000L);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    return "捡田螺的小男孩";
                }
        );

        CompletableFuture<String> rstFuture = orgFuture.handle((a, throwable) -> {

            System.out.println("上个任务执行完啦，还把" + a + "传过来");
            if ("捡田螺的小男孩".equals(a)) {
                System.out.println("666");
                return "关注了";
            }
            System.out.println("233333");
            return null;
        });

        System.out.println(rstFuture.get());
    }
}
//输出
当前线程名称：ForkJoinPool.commonPool-worker-1
上个任务执行完啦，还把捡田螺的小男孩传过来
666
关注了

arduino复制代码public class ThenCombineTest {

    public static void main(String[] args) throws InterruptedException, ExecutionException, TimeoutException {

        CompletableFuture<String> first = CompletableFuture.completedFuture("第一个异步任务");
        ExecutorService executor = Executors.newFixedThreadPool(10);
        CompletableFuture<String> future = CompletableFuture
                //第二个异步任务
                .supplyAsync(() -> "第二个异步任务", executor)
                // (w, s) -> System.out.println(s) 是第三个任务
                .thenCombineAsync(first, (s, w) -> {
                    System.out.println(w);
                    System.out.println(s);
                    return "两个异步任务的组合";
                }, executor);
        System.out.println(future.join());
        executor.shutdown();

    }
}
//输出
第一个异步任务
第二个异步任务
两个异步任务的组合

kotlin复制代码public class AcceptEitherTest {
    public static void main(String[] args) {
        //第一个异步任务，休眠2秒，保证它执行晚点
        CompletableFuture<String> first = CompletableFuture.supplyAsync(()->{
            try{

                Thread.sleep(2000L);
                System.out.println("执行完第一个异步任务");}
                catch (Exception e){
                    return "第一个任务异常";
                }
            return "第一个异步任务";
        });
        ExecutorService executor = Executors.newSingleThreadExecutor();
        CompletableFuture<Void> future = CompletableFuture
                //第二个异步任务
                .supplyAsync(() -> {
                            System.out.println("执行完第二个任务");
                            return "第二个任务";}
                , executor)
                //第三个任务
                .acceptEitherAsync(first, System.out::println, executor);

        executor.shutdown();
    }
}
//输出
执行完第二个任务
第二个任务

kotlin复制代码public class allOfFutureTest {
    public static void main(String[] args) throws ExecutionException, InterruptedException {

        CompletableFuture<Void> a = CompletableFuture.runAsync(()->{
            System.out.println("我执行完了");
        });
        CompletableFuture<Void> b = CompletableFuture.runAsync(() -> {
            System.out.println("我也执行完了");
        });
        CompletableFuture<Void> allOfFuture = CompletableFuture.allOf(a, b).whenComplete((m,k)->{
            System.out.println("finish");
        });
    }
}
//输出
我执行完了
我也执行完了
finish

csharp复制代码public class AnyOfFutureTest {
    public static void main(String[] args) throws ExecutionException, InterruptedException {

        CompletableFuture<Void> a = CompletableFuture.runAsync(()->{
            try {
                Thread.sleep(3000L);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("我执行完了");
        });
        CompletableFuture<Void> b = CompletableFuture.runAsync(() -> {
            System.out.println("我也执行完了");
        });
        CompletableFuture<Object> anyOfFuture = CompletableFuture.anyOf(a, b).whenComplete((m,k)->{
            System.out.println("finish");
//            return "捡田螺的小男孩";
        });
        anyOfFuture.join();
    }
}
//输出
我也执行完了
finish

arduino复制代码public class ThenComposeTest {
    public static void main(String[] args) throws ExecutionException, InterruptedException {

        CompletableFuture<String> f = CompletableFuture.completedFuture("第一个任务");
        //第二个异步任务
        ExecutorService executor = Executors.newSingleThreadExecutor();
        CompletableFuture<String> future = CompletableFuture
                .supplyAsync(() -> "第二个任务", executor)
                .thenComposeAsync(data -> {
                    System.out.println(data); return f; //使用第一个任务作为返回
                }, executor);
        System.out.println(future.join());
        executor.shutdown();

    }
}
//输出
第二个任务
第一个任务

ini复制代码ExecutorService executorService = new ThreadPoolExecutor(5, 10, 5L,
    TimeUnit.SECONDS, new ArrayBlockingQueue<>(10));
CompletableFuture<Void> future = CompletableFuture.supplyAsync(() -> {
      int a = 0;
      int b = 666;
      int c = b / a;
      return true;
   },executorService).thenAccept(System.out::println);
   
 //如果不加 get()方法这一行，看不到异常信息
 //future.get();

csharp复制代码//反例
 CompletableFuture.get();
//正例
CompletableFuture.get(5, TimeUnit.SECONDS);