复制代码public class Stack<E> extends Vector<E>

复制代码protected Object[] elementData;

复制代码private static final Object[]

复制代码    //数组中元素数量
    protected int elementCount;
    //增长量
    protected int capacityIncrement;

复制代码    //无参构造，数组容量默认是10
    public Vector() {
        this(10);
    }

复制代码    //默认容量
    private static final int DEFAULT_CAPACITY = 10;

    //构造指定容量的数组（10）
    public ArrayList() {
        this.elementData = DEFAULTCAPACITY_EMPTY_ELEMENTDATA;
    }

复制代码    //创建指定容量大小的数组，设置增长量。
    public Vector(int initialCapacity, int capacityIncrement) {
        super();
        if (initialCapacity < 0)
            throw new IllegalArgumentException("Illegal Capacity: "+
                                               initialCapacity);
        //构造指定容量的数组
        this.elementData = new Object[initialCapacity];
        //设置增长量
        this.capacityIncrement = capacityIncrement;
    }

复制代码    public Vector(int initialCapacity) {
        this(initialCapacity, 0);
    }

复制代码    public Vector(Collection<? extends E> c) {
        //转成数组，赋值
        elementData = c.toArray();
        elementCount = elementData.length;
        // c.toArray might (incorrectly) not return Object[] (see 6260652)
        //如果不是Object[]，要重建数组
        if (elementData.getClass() != Object[].class)
            elementData = Arrays.copyOf(elementData, elementCount, Object[].class);
    }

复制代码    private void ensureCapacityHelper(int minCapacity) {
        // overflow-conscious code
        if (minCapacity - elementData.length > 0)
            grow(minCapacity);
    }

复制代码    //最小数组容量
    private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;

    //扩容
    private void grow(int minCapacity) {
        //旧的数组容量
        int oldCapacity = elementData.length;
        //新数组容量
        //如果当前数组的增长量 > 0则新数组容量 = 旧数组容量 + 增长量
        //否则，则新数组容量 = 2 * 旧数组容量
        int newCapacity = oldCapacity + ((capacityIncrement > 0) ?
                                         capacityIncrement : oldCapacity);
        //求出新数组容量后，如果新数组容量 < 最小容量，那么新数组容量 = 最小容量                                  
        if (newCapacity - minCapacity < 0)
            newCapacity = minCapacity;
        //如果新数组容量 > 最大数组容量，则新数组容量 = 整数最大值
        if (newCapacity - MAX_ARRAY_SIZE > 0)
            newCapacity = hugeCapacity(minCapacity);
        //真正扩容，实际上就是数组的复制和移动    
        elementData = Arrays.copyOf(elementData, newCapacity);
    }

    //判断是取最大数组容量还是整数最大值
    private static int hugeCapacity(int minCapacity) {
        if (minCapacity < 0) // overflow
            throw new OutOfMemoryError();
        return (minCapacity > MAX_ARRAY_SIZE) ?
            Integer.MAX_VALUE :
            MAX_ARRAY_SIZE;
    }

复制代码    public static <T,U> T[] copyOf(U[] original, int newLength, Class<? extends T[]> newType) {
        @SuppressWarnings("unchecked")
        T[] copy = ((Object)newType == (Object)Object[].class)
            ? (T[]) new Object[newLength]
            : (T[]) Array.newInstance(newType.getComponentType(), newLength);
        //params0：original：原数组
        //param1：srcPos：原数组开始位置
        //param2：copy：新数组
        //param3：destPost：新数组开始位置
        //param4：copyLength：要copy的数组的长度    
        System.arraycopy(original, 0, copy, 0,
                         Math.min(original.length, newLength));
        return copy;
    }

复制代码    private void grow(int minCapacity) {
        // 原来的数组容量 = 数组长度
        int oldCapacity = elementData.length;
        // 新的数组容量 = 原数组容量+原数组容量/2
        int newCapacity = oldCapacity + (oldCapacity >> 1);
        //判断下传进来的最小容量 （最小容量 = 当前数组元素数目 + 1）
        // 如果比当前新数组容量小，则使用最容量
        if (newCapacity - minCapacity < 0)
            newCapacity = minCapacity;
        //如果判断当前新容量是否超过最大的数组容量 MAX_ARRAY_SIZE =  Integer.MAX_VALUE - 8
        if (newCapacity - MAX_ARRAY_SIZE > 0)
            newCapacity = hugeCapacity(minCapacity);
        //开始扩容
        elementData = Arrays.copyOf(elementData, newCapacity);
    }
    
    //如果判断当前新容量是否超过最大的数组容量 MAX_ARRAY_SIZE =  Integer.MAX_VALUE - 8
    private static int hugeCapacity(int minCapacity) {
        if (minCapacity < 0) // overflow
            throw new OutOfMemoryError();
        //如果超多最大数组容量则使用Integer的最大数值，否则还是使用最大数组容量
        return (minCapacity > MAX_ARRAY_SIZE) ?
            Integer.MAX_VALUE :
            MAX_ARRAY_SIZE;
    }

复制代码    public synchronized void addElement(E obj) {
        modCount++;
        //判断是否需要扩容
        ensureCapacityHelper(elementCount + 1);
        //直接根据下标添加
        elementData[elementCount++] = obj;
    }

复制代码    public synchronized void insertElementAt(E obj, int index) {
        modCount++;
        if (index > elementCount) {
            throw new ArrayIndexOutOfBoundsException(index
                                                     + " > " + elementCount);
        }
        //判断是否需要扩容
        ensureCapacityHelper(elementCount + 1);
        //数组移动和复制，腾出index位置 index后的元素向后移动一位
        System.arraycopy(elementData, index, elementData, index + 1, elementCount - index);
        //下标添加
        elementData[index] = obj;
        //元素数量+1
        elementCount++;
    }

复制代码    public synchronized boolean addAll(Collection<? extends E> c) {
        modCount++;
        Object[] a = c.toArray();
        int numNew = a.length;
        ensureCapacityHelper(elementCount + numNew);
         //扩容，复制到数组后面
        System.arraycopy(a, 0, elementData, elementCount, numNew);
        elementCount += numNew;
        return numNew != 0;
    }

复制代码    public synchronized E remove(int index) {
        modCount++;
        if (index >= elementCount)
            throw new ArrayIndexOutOfBoundsException(index);
        //原来该下标对应的元素值    
        E oldValue = elementData(index);
        //index后面元素的数量
        int numMoved = elementCount - index - 1;
        //如果该元素不是最后一个元素
        if (numMoved > 0)
            //该元素后面的元素向前移动一位，覆盖删除
            System.arraycopy(elementData, index+1, elementData, index,
                             numMoved);
        //数组最后多余的一位为null，gc                     
        elementData[--elementCount] = null; // Let gc do its work

        return oldValue;
    }

    //和上边方法其实思路是一样的
    public synchronized void removeElementAt(int index) {
        modCount++;
        //检查
        if (index >= elementCount) {
            throw new ArrayIndexOutOfBoundsException(index + " >= " +
                                                     elementCount);
        }
        else if (index < 0) {
            throw new ArrayIndexOutOfBoundsException(index);
        }
        int j = elementCount - index - 1;
        if (j > 0) {
             //该元素后面的元素向前移动一位，覆盖删除
            System.arraycopy(elementData, index + 1, elementData, index, j);
        }
        //数组最后多余的一位为null，gc    
        elementCount--;
        elementData[elementCount] = null; /* to let gc do its work */
    }

复制代码    public synchronized boolean removeElement(Object obj) {
        modCount++;
        //找到该元素下标
        int i = indexOf(obj);
        if (i >= 0) {
            //下标正确则根据下标删除
            removeElementAt(i);
            return true;
        }
        return false;
    }

复制代码    public synchronized void removeAllElements() {
        modCount++;
        //循环删除每一个元素，gc
        for (int i = 0; i < elementCount; i++)
            elementData[i] = null;

        elementCount = 0;
    }

复制代码    protected synchronized void removeRange(int fromIndex, int toIndex) {
        modCount++;
        //原理还是数组的移动，将toIndex后的元素向前移动 toIndex - fromIndex
        int numMoved = elementCount - toIndex;
        System.arraycopy(elementData, toIndex, elementData, fromIndex,
                         numMoved);

        // Let gc do its work
        int newElementCount = elementCount - (toIndex-fromIndex);
        while (elementCount != newElementCount)
            elementData[--elementCount] = null;
    }

复制代码    public synchronized int indexOf(Object o, int index) {
        if (o == null) {
            for (int i = index ; i < elementCount ; i++)
                if (elementData[i]==null)
                    return i;
        } else {
            for (int i = index ; i < elementCount ; i++)
                if (o.equals(elementData[i]))
                    return i;
        }
        return -1;
    }

复制代码    public synchronized int lastIndexOf(Object o, int index) {
        if (index >= elementCount)
            throw new IndexOutOfBoundsException(index + " >= "+ elementCount);

        if (o == null) {
            for (int i = index; i >= 0; i--)
                if (elementData[i]==null)
                    return i;
        } else {
            for (int i = index; i >= 0; i--)
                if (o.equals(elementData[i]))
                    return i;
        }
        return -1;
    }

复制代码    E elementData(int index) {
        return (E) elementData[index];
    }

    public synchronized E get(int index) {
        if (index >= elementCount)
            throw new ArrayIndexOutOfBoundsException(index);

        return elementData(index);
    }

复制代码    //看没有该下标
    public boolean contains(Object o) {
        return indexOf(o, 0) >= 0;
    }

复制代码格式：
adb -s 225278f8 shell

获取设备序列号:
adb devices

复制代码格式：
google.architecture.universal/.ActivityMain

打开Apk，然后输入下面命令查看：
adb shell dumpsys window | grep mCurrentFocus

复制代码List of devices attached 
2aca417d	no permissions

复制代码Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 413c:2113 Dell Computer Corp. 
Bus 001 Device 002: ID 413c:301a Dell Computer Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

复制代码Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 413c:2113 Dell Computer Corp. 
Bus 001 Device 002: ID 413c:301a Dell Computer Corp. 
Bus 001 Device 055: ID 18d1:4ee7 Google Inc. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

复制代码# 打开一个文件
sudo vim 51-android.rules

# 添加端口信息到51-android.rules
SUBSYSTEM=="usb",ATTRS{idVendor}=="18d1",ATTRS{idProduct}=="4ee7",MODE="0666"

复制代码sudo chmod a+rx /etc/udev/rules.d/51-android.rules
sudo service udev restart

复制代码sudo adb kill-server
sudo adb start-server
sudo adb devices

复制代码List of devices attached 
2aca417d  device

复制代码android {
    ...
    dataBinding {
        enabled = true
    }
}

复制代码<ImageView
    android:id="@+id/imageView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:tint="@{user.likes &gt; 9 ? @color/star : @android:color/black}"
    app:srcCompat="@{user.likes &lt; 4 ? R.drawable.ic_person_black_96dp : R.drawable.ic_whatshot_black_96dp }" />

复制代码public class TestProfile {
    private String name;
    private String lastName;
    private int likes;

    public TestProfile(String name, String lastName, int likes) {
        this.name = name;
        this.lastName = lastName;
        this.likes = likes;
    }
    //省略getter/setter...
}

复制代码public class TestProfile {
    private String name;
    private String lastName;
    //改为支持单向绑定的ObservableInt
    private ObservableInt likes;

    public TestProfile(String name, String lastName, ObservableInt likes) {
        this.name = name;
        this.lastName = lastName;
        this.likes = likes;
    }
    //省略getter/setter...
}

复制代码# ObservableFieldProfileBindingImpl
protected void executeBindings() {
    ...
    //TestProfile中的ObservableInt对象
    androidx.databinding.ObservableInt userLikes = null;
    //mUser为实际binding的对象
    com.example.android.databinding.basicsample.data.TestProfile user = mUser;
    //ObservableInt属性值
    int userLikesGet = 0;

    if ((dirtyFlags & 0x7L) != 0) {

		//第一步验空 user验空
        if (user != null) {
            // read user.likes
            userLikes = user.getLikes();
        }
        updateRegistration(0, userLikes);

        //第二步验空 ObservableInt验空
        if (userLikes != null) {
            // read user.likes.get()
            userLikesGet = userLikes.get();
        }
        ...
    }    
}

复制代码class MyCustomView : View {
    var mDrawable: Drawable? = null

    constructor(context: Context?, attrs: AttributeSet?) : super(context, attrs) {
        val typedArray = context!!.theme.obtainStyledAttributes(attrs,
                R.styleable.MyCustomView, 0, 0)
        mDrawable = typedArray.getDrawable(R.styleable.MyCustomView_img)
        typedArray.recycle()
    }

    override fun onDraw(canvas: Canvas?) {
        mDrawable?.run {
            setBounds(0, 0, this.intrinsicWidth, this.intrinsicHeight)
            draw(canvas!!)
        }
    }
}

复制代码<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <data>
        <variable
            name="myDrawable"
            type="android.graphics.drawable.Drawable" />
    </data>
    <com.example.android.databinding.basicsample.ui.MyCustomView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:img="@{myDrawable}" />
</layout>

复制代码val binding: TestCustomViewBinding = DataBindingUtil.setContentView(this, R.layout.test_custom_view)
binding.myDrawable = resources.getDrawable(R.mipmap.ic_launcher)

复制代码****/ data binding error ****msg:Cannot find the setter for attribute 'app:img' with parameter type android.graphics.drawable.Drawable on com.example.android.databinding.basicsample.ui.MyCustomView.
file:/android-databinding/BasicSample/app/src/main/res/layout/test_custom_view.xml loc:14:19 - 14:28 ****\ data binding error ****

复制代码class MyCustomView : View {
    ...
    fun setImg(d: Drawable) {
        mDrawable = d
    }
}

复制代码# BindingAdapters.kt
...
@BindingAdapter("img")
@JvmStatic
fun setImg(view: MyCustomView, drawable: Drawable) {
    view.setMyImg(drawable)
}

复制代码@BindingAdapter("img")
@JvmStatic
//old为绑定发生前img的属性值
fun yyy(view: MyCustomView, old: Drawable?, drawable: Drawable) {
    view.setMyImg(drawable)
}

复制代码@BindingAdapter(value = ["property1", "property2"], requireAll = false)

复制代码@BindingMethods(BindingMethod(type = MyCustomView::class, attribute = "img", method = "setMyImg"))
class MyCustomView : View {
    ...
}

复制代码@BindingMethods({
        @BindingMethod(type = View.class, attribute = "android:backgroundTint", method = "setBackgroundTintList"),
        @BindingMethod(type = View.class, attribute = "android:nextFocusLeft", method = "setNextFocusLeftId"),
        ...
        @BindingMethod(type = View.class, attribute = "android:onLongClick", method = "setOnLongClickListener"),
        @BindingMethod(type = View.class, attribute = "android:onTouch", method = "setOnTouchListener"),
})
public class ViewBindingAdapter {
    @BindingAdapter({"android:padding"})
    public static void setPadding(View view, float paddingFloat) {
        final int padding = pixelsToDimensionPixelSize(paddingFloat);
        view.setPadding(padding, padding, padding, padding);
    }
    ...
}

复制代码@BindingAdapter("android:layout_marginBottom")
public static void setBottomMargin(View view, float bottomMargin) {
    MarginLayoutParams layoutParams = (MarginLayoutParams) view.getLayoutParams();
    layoutParams.setMargins(layoutParams.leftMargin, layoutParams.topMargin,
        layoutParams.rightMargin, Math.round(bottomMargin));
    view.setLayoutParams(layoutParams);
}

复制代码data class ObservableFieldProfile(
        var likes: Int
)

复制代码<layout

    <data>
        <variable
            name="user"
            type="com.example.android.databinding.basicsample.data.ObservableFieldProfile" />
    </data>

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        ...
        android:src="@{user.likes &lt; 4 ? R.drawable.ic1 : R.drawable.ic2 }"/>
</layout>

复制代码val binding: ObservableFieldProfileBinding =
        DataBindingUtil.setContentView(this, R.layout.observable_field_profile)
val user = ObservableFieldProfile(0)
binding.user = user

复制代码data class ObservableFieldProfile(
        val likes: ObservableInt
)

复制代码class ObservableFieldProfile(var name: String, val lastName: String) : BaseObservable() {

    constructor(name: String, lastName: String, likes: Int) : this(name, lastName) {
        this.likes = likes
    }

    @get:Bindable
    var likes: Int = 0
        set(value) {
            field = value
            notifyPropertyChanged(BR.likes)
        }
}

复制代码class ProfileLiveDataViewModel : ViewModel() {
    val likes: MutableLiveData<Int> = MutableLiveData(0)
}

复制代码<layout
    xmlns:android="http://schemas.android.com/apk/res/android">
    <data>
        <variable
            name="viewmodel"
            type="com.example.android.databinding.basicsample.data.ProfileLiveDataViewModel"/>
    </data>
    
    <TextView
        android:id="@+id/likes"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@{Integer.toString(viewmodel.likes+1)}"
        .../>

复制代码# viewmodel
fun testConvert(likes: Int): String {
    return Integer.toString(likes + 1)
}

复制代码# viewmodel
fun testConvert2(): String {
    return Integer.toString(likes.value?.plus(1) ?: 0)
}

复制代码// dirty flag
private  long mDirtyFlags = 0xffffffffffffffffL;
/* flag mapping
    flag 0 (0x1L): viewmodel.likes
    flag 1 (0x2L): viewmodel.lastName
    flag 2 (0x3L): viewmodel.popularity
    flag 3 (0x4L): viewmodel.name
    flag 4 (0x5L): viewmodel
    flag 5 (0x6L): null
flag mapping end*/
//end

复制代码# TextViewBindingAdapter
①  //event可缺省
@InverseBindingAdapter(attribute = "android:text", event = "android:textAttrChanged")
public static String getTextString(TextView view) {
    return view.getText().toString();
}

②
@BindingAdapter(value = { ..., "android:textAttrChanged"}, requireAll = false)
public static void setTextWatcher(TextView view, ...,
        final InverseBindingListener textAttrChanged) {
    final TextWatcher newValue;
    ...
    newValue = new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
            ...
        }
        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            ...
            //收到事件 通知框架发生变化
            if (textAttrChanged != null) {
                textAttrChanged.onChange();
            }
        }
        @Override
        public void afterTextChanged(Editable s) {
            ...
        }
    };
    ...
    if (newValue != null) {
        view.addTextChangedListener(newValue);
    }
}

复制代码@InverseBindingMethods({@InverseBindingMethod(
     type = android.widget.TextView.class,
     attribute = "android:text",
     event = "android:textAttrChanged",
     method = "getText")})
 public class MyTextViewBindingAdapters

复制代码@BindingAdapter("android:text")
public static void setText(TextView view, CharSequence text) {
    //校验
    final CharSequence oldText = view.getText();
    if (text == oldText || (text == null && oldText.length() == 0)) {
        return;
    }
    ...
    view.setText(text);
}

复制代码dependencies {
    pmd "com.alibaba.p3c:p3c-pmd:2.0.0"
}

复制代码<?xml version="1.0"?>
<ruleset name="Custom ruleset"
         xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 http://pmd.sourceforge.net/ruleset_2_0_0.xsd">
    <description>
        自定义Rule set
    </description>
    <!-- 引入PMD制定的Rule, 来源于https://github.com/pmd/pmd/tree/master/pmd-java/src/main/resources/rulesets/java  -->
    <rule ref="rulesets/java/android.xml">
        <exclude name="CallSuperLast"/>
    </rule>
    <rule ref="rulesets/java/basic.xml">
        <exclude name="CollapsibleIfStatements"/>
    </rule>
    <rule ref="rulesets/java/clone.xml"/>
    <rule ref="rulesets/java/finalizers.xml"/>
    <rule ref="rulesets/java/imports.xml"/>
    <rule ref="rulesets/java/javabeans.xml"/>

    <rule ref="rulesets/java/optimizations.xml">
        <exclude name="LocalVariableCouldBeFinal"/>
        <exclude name="MethodArgumentCouldBeFinal"/>
    </rule>
    <rule ref="rulesets/java/sunsecure.xml"/>

    <rule ref="rulesets/java/unnecessary.xml">
        <exclude name="UselessParentheses"/>
    </rule>

    <!-- 引入阿里的Rule, 来源于 https://github.com/alibaba/p3c/tree/master/p3c-pmd/src/main/resources/rulesets/java -->
    <rule ref="rulesets/java/ali-comment.xml">
    </rule>

    <rule ref="rulesets/java/ali-concurrent.xml">
    </rule>

    <rule ref="rulesets/java/ali-constant.xml">
    </rule>

    <rule ref="rulesets/java/ali-exception.xml">
    </rule>

    <rule ref="rulesets/java/ali-flowcontrol.xml">
    </rule>

    <rule ref="rulesets/java/ali-naming.xml">
    </rule>

    <rule ref="rulesets/java/ali-oop.xml">
    </rule>

    <rule ref="rulesets/java/ali-orm.xml">
    </rule>

    <rule ref="rulesets/java/ali-other.xml">
    </rule>

    <rule ref="rulesets/java/ali-set.xml">
    </rule>

</ruleset>

复制代码apply plugin: "pmd"

pmd {
    toolVersion = '6.17.0'
    ignoreFailures = true
    ruleSetConfig = resources.text.fromFile("etc/pmd/ruleset.xml")
}

dependencies {
    pmd "com.alibaba.p3c:p3c-pmd:2.0.0"
    ...
}

复制代码gradle pmdMain
gradle pmdTest

复制代码public static void main( String args[] ){

        // 按指定模式在字符串查找
        String line = "123ra9040 123123aj234 adf12322ad 222jsk22";
        String pattern = "(\\d+)([a-z]+)(\\d+)";
//        String pattern1 = "([\\u4E00-\\u9FA5]+|\\w+)";

        // 创建 Pattern 对象
        Pattern r = Pattern.compile(pattern);

        // 现在创建 matcher 对象
        Matcher m = r.matcher(line);
        int i = 0;
        // m.find 是否找到正则表达式中符合条件的字符串
        while (m.find( )) {
            // 拿到上面匹配到的数据
            System.out.println("----i="+i);
            System.out.println("Found value: " + m.group(0) );
            System.out.println("Found value: " + m.group(1) );
            System.out.println("Found value: " + m.group(2) );
            System.out.println("Found value: " + m.group(3) );
            i++;
            System.out.println("|||||||");
            System.out.println("");
        }
    }

复制代码----i=0
Found value: 123ra9040
Found value: 123
Found value: ra
Found value: 9040
|||||||

----i=1
Found value: 123123aj234
Found value: 123123
Found value: aj
Found value: 234
|||||||

----i=2
Found value: 222jsk22
Found value: 222
Found value: jsk
Found value: 22
|||||||

复制代码Arrays.sort(new Integer[]{1, 8, 7, 4}, new Comparator<Integer>() {
   @Override
   public int compare(Integer first, Integer second) {
       return first.compareTo(second);
   }
});

复制代码Arrays.sort(new Integer[]{1, 8, 7, 4},
	(first,second) -> first.compareTo(second));

复制代码(n) -> n*n

复制代码(n) -> {
	if( n <= 10) 
		return n*n;
	return n * 10;
}

复制代码button.setOnAction(event -> System.out.println(event));

复制代码
button.setOnAction(System.out::println);

复制代码List<String> strList = Arrays.asList("1","2","3");
Stream<Integer> stream =  strList.stream().map(Integer::new);

复制代码Map<String,Map<String,Integer>> resultMap = new HashMap<>();
Map<String,Integer> maleMap = new HashMap<>();
Map<String,Integer> femaleMap = new HashMap<>();

resultMap.put("male", maleMap);
resultMap.put("female",femaleMap);

for(int i = 0; i < list.size(); i++) {
    Person person = list.get(i);
    String gender = person.getGender();
    String level = person.getLevel();
    switch (gender) {
        case "male":
            Integer maleCount;
            if("gold".equals(level)) {
                maleCount = maleMap.get("gold");
                maleMap.put("gold", null != maleCount ? maleCount + 1 : 1);
            } else if("soliver".equals(level)){
                maleCount = maleMap.get("soliver");
                maleMap.put("soliver", null != maleCount ? maleCount + 1 : 1);
            }
            break;

        case "female":
            Integer femaleCount;
            if("gold".equals(level)) {
                femaleCount = femaleMap.get("gold");
                femaleMap.put("gold", null != femaleCount ? femaleCount + 1 : 1);
            } else if("soliver".equals(level)){
                femaleCount = femaleMap.get("soliver");
                femaleMap.put("soliver", null != femaleCount ? femaleCount + 1 : 1);
            }
            break;

    }
}

复制代码Map<String,Map<String,Integer>> result = list.stream().collect(
    Collectors.toMap(
	    person -> person.getGender(),
	    person -> Collections.singletonMap(person.getLevel(), 1),
	    (existValue,newValue) -> {
	        HashMap<String,Integer> newMap = new HashMap<>(existValue);
	        newValue.forEach((key,value) ->{
	            if(newMap.containsKey(key)) {
	                newMap.put(key, newMap.get(key) + 1);
	            } else {
	                newMap.put(key, value);
	            }
	        });
	        return newMap;
	    })
);

复制代码Map<String,Map<String,Integer>> result =  stream.collect(
    Collectors.groupingBy(
        Person::getGender, 
        Collectors.toMap(
            person->person.getLevel(), 
            person -> 1,
            (existValue,newValue) -> existValue + newValue
        )
    )
);

复制代码Stream<String[]>	-> flatMap ->	Stream<String>
Stream<Set<String>>	-> flatMap ->	Stream<String>
Stream<List<String>>	-> flatMap ->	Stream<String>
Stream<List<Object>>	-> flatMap ->	Stream<Object>

{{1,2}, {3,4}, {5,6} } -> flatMap -> {1,2,3,4,5,6}

复制代码
int sum = 0;
for(int value in values) {
	sum = sum + value;
}

复制代码values.stream().reduce(Integer::sum);

复制代码代码效果：[a,b,c,c,c]  -> a:1,b:1,c:3

Arrays.asList("a","b","c","c","c").stream().collect(Collectors.groupingBy(str->str, Collectors.counting()));

复制代码List<String> myList = Arrays.asList("a","b","c","c","c");
myList.stream().collect(Collectors.joining(",","{","}"));

复制代码myList.stream().anyMatch(s -> !s.isEmpty());

复制代码import { provide, controller, inject, get } from 'midway';

@provide()
@controller('/user')
export class UserController {

  @inject('userService')
  service: IUserService;

  @get('/:id')
  async getUser(ctx): Promise<void> {
    const id: number = ctx.params.id;
    const user: IUserResult = await this.service.getUser({id});
    ctx.body = {success: true, message: 'OK', data: user};
  }
}

复制代码├── README.md
├── README.zh-CN.md
├── dist                                ---- 编译后目录
├── logs                                ---- 本地日志目录
│   └── midway6-test                    ---- 日志应用名开头
│       ├── common-error.log            ---- 错误日志
│       ├── midway-agent.log            ---- agent 输出的日志
│       ├── midway-core.log             ---- 框架输出的日志
│       ├── midway-web.log              ---- koa 输出的日志
│       └── midway6-test-web.log
├── package.json
├── src                                 ---- 源码目录
│   ├── app                             ---- web 层目录
│   │   ├── controller                  ---- web 层 controller 目录
│   │   │   ├── home.ts
│   │   │   └── user.ts
│   │   ├── middleware (可选)            ---- web 层中间件目录
│   │   │   └── trace.ts
│   │   ├── public (可选)                ---- web 层静态文件目录，可以配置
│   │   ├── view (可选)
│   │   |   └── home.tpl                ---- web 层模板
│   ├── config
│   │   ├── config.default.ts
│   │   ├── config.local.ts
│   │   ├── config.prod.ts
│   │   ├── config.unittest.ts
│   │   └── plugin.ts
│   └── lib                             ---- 业务逻辑层目录，自由定义
│   │   └── service                     ---- 业务逻辑层，自由定义
│   │       └── user.ts   
│   ├── interface.ts                    ---- 接口定义文件，自由定义
│   ├── app.ts                          ---- 应用扩展文件，可选
│   └── agent.ts                        ---- agent 扩展文件，可选
├── test
│   └── app
│       └── controller
│           └── home.test.ts
├── tsconfig.json
└── tslint.json

复制代码private def maybeValidateAppend(producerEpoch: Short, firstSeq: Int, offset: Long): Unit = {    validationType match {      case ValidationType.None =>      case ValidationType.EpochOnly =>        checkProducerEpoch(producerEpoch, offset)      case ValidationType.Full =>        checkProducerEpoch(producerEpoch, offset)        checkSequence(producerEpoch, firstSeq, offset)    }}private def checkSequence(producerEpoch: Short, appendFirstSeq: Int, offset: Long): Unit = {  if (producerEpoch != updatedEntry.producerEpoch) {    if (appendFirstSeq != 0) {      if (updatedEntry.producerEpoch != RecordBatch.NO_PRODUCER_EPOCH) {        throw new OutOfOrderSequenceException(s"Invalid sequence number for new epoch at offset $offset in " +          s"partition $topicPartition: $producerEpoch (request epoch), $appendFirstSeq (seq. number)")      } else {        throw new UnknownProducerIdException(s"Found no record of producerId=$producerId on the broker at offset $offset" +          s"in partition $topicPartition. It is possible that the last message with the producerId=$producerId has " +          "been removed due to hitting the retention limit.")      }    }  } else {    val currentLastSeq = if (!updatedEntry.isEmpty)      updatedEntry.lastSeq    else if (producerEpoch == currentEntry.producerEpoch)      currentEntry.lastSeq    else      RecordBatch.NO_SEQUENCE    if (currentLastSeq == RecordBatch.NO_SEQUENCE && appendFirstSeq != 0) {ne throw mew UnknownProducerIdException(s"Local producer state matches expected epoch $producerEpoch " +        s"for producerId=$producerId at offset $offset in partition $topicPartition, but the next expected " +        "sequence number is not known.")    } else if (!inSequence(currentLastSeq, appendFirstSeq)) {      throw new OutOfOrderSequenceException(s"Out of order sequence number for producerId $producerId at " +        s"offset $offset in partition $topicPartition: $appendFirstSeq (incoming seq. number), " +        s"$currentLastSeq (current end sequence number)")    }  }}  private def inSequence(lastSeq: Int, nextSeq: Int): Boolean = {    nextSeq == lastSeq + 1L || (nextSeq == 0 && lastSeq == Int.MaxValue)  }

复制代码    private void insertInSequenceOrder(Deque<ProducerBatch> deque, ProducerBatch batch) {        // When we are requeing and have enabled idempotence, the reenqueued batch must always have a sequence.        if (batch.baseSequence() == RecordBatch.NO_SEQUENCE)            throw new IllegalStateException("Trying to re-enqueue a batch which doesn't have a sequence even " +                "though idempotency is enabled.");        if (transactionManager.nextBatchBySequence(batch.topicPartition) == null)            throw new IllegalStateException("We are re-enqueueing a batch which is not tracked as part of the in flight " +                "requests. batch.topicPartition: " + batch.topicPartition + "; batch.baseSequence: " + batch.baseSequence());        ProducerBatch firstBatchInQueue = deque.peekFirst();        if (firstBatchInQueue != null && firstBatchInQueue.hasSequence() && firstBatchInQueue.baseSequence() < batch.baseSequence()) {            List<ProducerBatch> orderedBatches = new ArrayList<>();            while (deque.peekFirst() != null && deque.peekFirst().hasSequence() && deque.peekFirst().baseSequence() < batch.baseSequence())                orderedBatches.add(deque.pollFirst());            log.debug("Reordered incoming batch with sequence {} for partition {}. It was placed in the queue at " +                "position {}", batch.baseSequence(), batch.topicPartition, orderedBatches.size())            deque.addFirst(batch);            // Now we have to re insert the previously queued batches in the right order.            for (int i = orderedBatches.size() - 1; i >= 0; --i) {                deque.addFirst(orderedBatches.get(i));            }            // At this point, the incoming batch has been queued in the correct place according to its sequence.        } else {            deque.addFirst(batch);        }    }

复制代码private def maybeValidateAppend(producerEpoch: Short, firstSeq: Int, offset: Long): Unit = {    validationType match {      case ValidationType.None =>      case ValidationType.EpochOnly =>        checkProducerEpoch(producerEpoch, offset)      case ValidationType.Full => //开始事务，执行这个判断        checkProducerEpoch(producerEpoch, offset)        checkSequence(producerEpoch, firstSeq, offset)    }}private def checkProducerEpoch(producerEpoch: Short, offset: Long): Unit = {    if (producerEpoch < updatedEntry.producerEpoch) {      throw new ProducerFencedException(s"Producer's epoch at offset $offset is no longer valid in " +        s"partition $topicPartition: $producerEpoch (request epoch), ${updatedEntry.producerEpoch} (current epoch)")    }  }

复制代码if(cache.contain(msgId)){  // cache中包含msgId，已经处理过        continue;}else {  lock.lock();  cache.put(msgId,timeout);  commitSync();  lock.unLock();}// 后续完成所有操作后，删除cache中的msgId，只要msgId存在cache中，就认为已经处理过。Note：需要给cache设置有消息

复制代码_.chain([1, 2, 3]).reverse().value();
// => [3, 2, 1]

复制代码_.chain = function(obj) {
 var instance = _(obj);
 instance._chain = true;
 return instance;
};

复制代码var _ = function(obj) {
 if (obj instanceof _) return obj;
 if (!(this instanceof _)) return new _(obj);
 this._wrapped = obj;
};

复制代码var part1 = _.chain([1, 2, 3]);
var part2 = part1.reverse();
var part3 = part2.value();

// 没有后续part1.reverse()操作的情况下
console.log(part1); // {__wrapped: [1, 2, 3], _chain: true}

console.log(part2); // {__wrapped: [3, 2, 1], _chain: true}

console.log(part3); // [3, 2, 1]

复制代码_.chain([1,2,3]).reverse().value()

复制代码var ArrayProto = Array.prototype;
// 遍历 数组 Array.prototype 的这些方法，赋值到 _.prototype 上
_.each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
 // 这里的`method`是 reverse 函数
 var method = ArrayProto[name];
 _.prototype[name] = function() {
 // 这里的obj 就是数组 [1, 2, 3]
 var obj = this._wrapped;
 // arguments  是参数集合，指定reverse 的this指向为obj，参数为arguments， 并执行这个函数函数。执行后 obj 则是 [3, 2, 1]
 method.apply(obj, arguments);
 if ((name === 'shift' || name === 'splice') && obj.length === 0) delete obj[0];
 // 重点在于这里 chainResult 函数。
 return chainResult(this, obj);
 };
});

复制代码// Helper function to continue chaining intermediate results.
var chainResult = function(instance, obj) {
 // 如果实例中有_chain 为 true 这个属性，则返回实例 支持链式调用的实例对象  { _chain: true, this._wrapped: [3, 2, 1] }，否则直接返回这个对象[3, 2, 1]。
 return instance._chain ? _(obj).chain() : obj;
};

复制代码_.prototype.value = function(){
 return this._wrapped;
}

复制代码_.prototype.toString = function() {
 return String(this._wrapped);
};

复制代码var String = function(){
 if(!(this instanceOf String)) return new String(obj);
}

复制代码var chainResult = function(instance, obj) {
 return instance._chain ? _(obj).chain() : obj;
};

复制代码_.mixin = function(obj) {
 // 遍历对象上的所有方法
 _.each(_.functions(obj), function(name) {
  // 比如 chain, obj['chain'] 函数，自定义的，则赋值到_[name] 上，func 就是该函数。也就是说自定义的方法，不仅_函数对象上有，而且`_.prototype`上也有
 var func = _[name] = obj[name];
 _.prototype[name] = function() {
  // 处理的数据对象
  var args = [this._wrapped];
  // 处理的数据对象 和 arguments 结合
  push.apply(args, arguments);
  // 链式调用  chain.apply(_, args) 参数又被加上了 _chain属性，支持链式调用。
  // _.chain = function(obj) {
  // var instance = _(obj);
  // instance._chain = true;
  // return instance;
  };
  return chainResult(this, func.apply(_, args));
 };
 });
 // 最终返回 _ 函数对象。
 return _;
};

_.mixin(_);

复制代码_.mixin({
 log: function(){
  console.log('哎呀，我被调用了');
 }
})
_.log() // 哎呀，我被调用了
_().log() // 哎呀，我被调用了

复制代码_.functions = _.methods = function(obj) {
 var names = [];
 for (var key in obj) {
 if (_.isFunction(obj[key])) names.push(key);
 }
 return names.sort();
};

复制代码var staticMethods = [];
var staticProperty = [];
for(var name in _){
 if(typeof _[name] === 'function'){
  staticMethods.push(name);
 }
 else{
  staticProperty.push(name);
 }
}
console.log(staticProperty); // ["VERSION", "templateSettings"] 两个
console.log(staticMethods); // ["after", "all", "allKeys", "any", "assign", ...] 138个

复制代码var prototypeMethods = [];
var prototypeProperty = [];
for(var name in _.prototype){
 if(typeof _.prototype[name] === 'function'){
  prototypeMethods.push(name);
 }
 else{
  prototypeProperty.push(name);
 }
}
console.log(prototypeProperty); // []
console.log(prototypeMethods); // ["after", "all", "allKeys", "any", "assign", ...] 152个

复制代码(function(){

}());

复制代码var root = typeof self == 'object' && self.self === self && self ||
 typeof global == 'object' && global.global === global && global ||
 this ||
 {};

复制代码if (typeof exports != 'undefined' && !exports.nodeType) {
 if (typeof module != 'undefined' && !module.nodeType && module.exports) {
 exports = module.exports = _;
 }
 exports._ = _;
} else {
 root._ = _;
}

复制代码if (typeof define == 'function' && define.amd) {
 define('underscore', [], function() {
  return _;
 });
}

复制代码// 暂存在 root 上， 执行noConflict时再赋值回来
var previousUnderscore = root._;
_.noConflict = function() {
 root._ = previousUnderscore;
 return this;
};

复制代码<script>
var _ = '我就是我，不一样的烟火，其他可不要覆盖我呀';
</script>
<script src="https://unpkg.com/underscore@1.9.1/underscore.js">
</script>
<script>
var underscore = _.noConflict();
console.log(_); // '我就是我，不一样的烟火，其他可不要覆盖我呀'
underscore.isArray([]) // true
</script>

复制代码(function() {
 var root = typeof self == 'object' && self.self === self && self ||
  typeof global == 'object' && global.global === global && global ||
  this ||
  {};
 var previousUnderscore = root._;

 var _ = function(obj) {
   if (obj instanceof _) return obj;
   if (!(this instanceof _)) return new _(obj);
   this._wrapped = obj;
 };

 if (typeof exports != 'undefined' && !exports.nodeType) {
   if (typeof module != 'undefined' && !module.nodeType && module.exports) {
  exports = module.exports = _;
   }
   exports._ = _;
 } else {
   root._ = _;
 }
 _.VERSION = '1.9.1';

 _.chain = function(obj) {
   var instance = _(obj);
   instance._chain = true;
   return instance;
 };

 var chainResult = function(instance, obj) {
   return instance._chain ? _(obj).chain() : obj;
 };

 _.mixin = function(obj) {
   _.each(_.functions(obj), function(name) {
  var func = _[name] = obj[name];
  _.prototype[name] = function() {
    var args = [this._wrapped];
    push.apply(args, arguments);
    return chainResult(this, func.apply(_, args));
  };
   });
   return _;
 };

 _.mixin(_);

 _.each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
   var method = ArrayProto[name];
   _.prototype[name] = function() {
  var obj = this._wrapped;
  method.apply(obj, arguments);
  if ((name === 'shift' || name === 'splice') && obj.length === 0) delete obj[0];
  return chainResult(this, obj);
   };
 });

 _.each(['concat', 'join', 'slice'], function(name) {
   var method = ArrayProto[name];
   _.prototype[name] = function() {
  return chainResult(this, method.apply(this._wrapped, arguments));
   };
 });

 _.prototype.value = function() {
   return this._wrapped;
 };

 _.prototype.valueOf = _.prototype.toJSON = _.prototype.value;

 _.prototype.toString = function() {
   return String(this._wrapped);
 };

 if (typeof define == 'function' && define.amd) {
   define('underscore', [], function() {
  return _;
   });
 }
}());

复制代码create table oms_order_return_apply
(
   id                   bigint not null auto_increment,
   order_id             bigint comment '订单id',
   company_address_id   bigint comment '收货地址表id',
   product_id           bigint comment '退货商品id',
   order_sn             varchar(64) comment '订单编号',
   create_time          datetime comment '申请时间',
   member_username      varchar(64) comment '会员用户名',
   return_amount        decimal(10,2) comment '退款金额',
   return_name          varchar(100) comment '退货人姓名',
   return_phone         varchar(100) comment '退货人电话',
   status               int(1) comment '申请状态：0->待处理；1->退货中；2->已完成；3->已拒绝',
   handle_time          datetime comment '处理时间',
   product_pic          varchar(500) comment '商品图片',
   product_name         varchar(200) comment '商品名称',
   product_brand        varchar(200) comment '商品品牌',
   product_attr         varchar(500) comment '商品销售属性：颜色：红色；尺码：xl;',
   product_count        int comment '退货数量',
   product_price        decimal(10,2) comment '商品单价',
   product_real_price   decimal(10,2) comment '商品实际支付单价',
   reason               varchar(200) comment '原因',
   description          varchar(500) comment '描述',
   proof_pics           varchar(1000) comment '凭证图片，以逗号隔开',
   handle_note          varchar(500) comment '处理备注',
   handle_man           varchar(100) comment '处理人员',
   receive_man          varchar(100) comment '收货人',
   receive_time         datetime comment '收货时间',
   receive_note         varchar(500) comment '收货备注',
   primary key (id)
);

复制代码create table oms_company_address
(
   id                   bigint not null auto_increment,
   address_name         varchar(200) comment '地址名称',
   send_status          int(1) comment '默认发货地址：0->否；1->是',
   receive_status       int(1) comment '是否默认收货地址：0->否；1->是',
   name                 varchar(64) comment '收发货人姓名',
   phone                varchar(64) comment '收货人电话',
   province             varchar(64) comment '省/直辖市',
   city                 varchar(64) comment '市',
   region               varchar(64) comment '区',
   detail_address       varchar(200) comment '详细地址',
   primary key (id)
);

复制代码create table oms_order_return_reason
(
   id                   bigint not null auto_increment,
   name                 varchar(100) comment '退货类型',
   sort                 int,
   status               int(1) comment '状态：0->不启用；1->启用',
   create_time          datetime comment '添加时间',
   primary key (id)
);