package com.test.proxy;
public interface Target {
public String execute();
}
package com.test.proxy;
public class TargetImpl implements Target {
@Override
public String execute() {
System.out.println("TargetImpl execute！");
return "execute";
}
}
package com.test.proxy;
public class Proxy implements Target{
private Target target;
public Proxy(Target target) {
this.target = target;
}
@Override
public String execute() {
System.out.println("perProcess");
String result = this.target.execute();
System.out.println("postProcess");
return result;
}
}
package com.test.proxy;
public class ProxyTest {
public static void main(String[] args) {
Target target = new TargetImpl();
Proxy p = new Proxy(target);
String result = p.execute();
System.out.println(result);
}
}
perProcess TargetImpl execute！ postProcess execute
package com.test.dynamic;
public interface Target {
public String execute();
}
package com.test.dynamic;
public class TargetImpl implements Target {
@Override
public String execute() {
System.out.println("TargetImpl execute！");
return "execute";
}
}
package com.test.dynamic;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
public class DynamicProxyHandler implements InvocationHandler{
private Target target;
public DynamicProxyHandler(Target target) {
this.target = target;
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
System.out.println("========before==========");
Object result = method.invoke(target,args);
System.out.println("========after===========");
return result;
}
}
package com.test.dynamic;
import java.lang.reflect.Proxy;
public class DynamicProxyTest {
public static void main(String[] args) {
Target target = new TargetImpl();
DynamicProxyHandler handler = new DynamicProxyHandler(target);
Target proxySubject = (Target) Proxy.newProxyInstance(TargetImpl.class.getClassLoader(),TargetImpl.class.getInterfaces(),handler);
String result = proxySubject.execute();
System.out.println(result);
}
}
========before========== TargetImpl execute！ ========after=========== execute
package com.test.cglib;
public class Target {
public String execute() {
String message = "-----------test------------";
System.out.println(message);
return message;
}
}
package com.test.cglib;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;
import java.lang.reflect.Method;
public class MyMethodInterceptor implements MethodInterceptor{
@Override
public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
System.out.println(">>>>MethodInterceptor start...");
Object result = proxy.invokeSuper(obj,args);
System.out.println(">>>>MethodInterceptor ending...");
return "result";
}
}
package com.test.cglib;
import net.sf.cglib.proxy.Enhancer;
public class CglibTest {
public static void main(String[] args) {
System.out.println("***************");
Target target = new Target();
CglibTest test = new CglibTest();
Target proxyTarget = (Target) test.createProxy(Target.class);
String res = proxyTarget.execute();
System.out.println(res);
}
public Object createProxy(Class targetClass) {
Enhancer enhancer = new Enhancer();
enhancer.setSuperclass(targetClass);
enhancer.setCallback(new MyMethodInterceptor());
return enhancer.create();
}
}
*************** >>>>MethodInterceptor start... -----------test------------ >>>>MethodInterceptor ending... result
public class Singleton2 {
private static Singleton2 instance;
private Singleton2() {}
public static synchronized Singleton2 getInstance() {
if (instance == null) {
instance = new Singleton2();
}
return instance;
}
}
public class Singleton3 {
private static Singleton3 instance = new Singleton3();
private Singleton3() {}
public static Singleton3 getInstance() {
return instance;
}
}
public class Singleton7 {
private static volatile Singleton7 instance = null;
private Singleton7() {}
public static Singleton7 getInstance() {
if (instance == null) {
synchronized (Singleton7.class) {
if (instance == null) {
instance = new Singleton7();
}
}
}
return instance;
}
}
public interface Shape {
void draw();
}
public class Rectangle implements Shape {
@Override
public void draw() {
System.out.println("Inside Rectangle::draw() method.");
}
}
public class Square implements Shape {
@Override
public void draw() {
System.out.println("Inside Square::draw() method.");
}
}
public class Circle implements Shape {
@Override
public void draw() {
System.out.println("Inside Circle::draw() method.");
}
}
public class ShapeFactory {
//使用 getShape 方法获取形状类型的对象
public Shape getShape(String shapeType) {
if (shapeType == null) {
return null;
}
shapeType = shapeType.toLowerCase();
switch (shapeType) {
case "circle":
return new Circle();
case "rectangle":
return new Rectangle();
case "square":
return new Square();
default:
return null;
}
}
}
public class FactoryPatternDemo {
public static void main(String[] args) {
ShapeFactory shapeFactory = new ShapeFactory();
//获取 Circle 的对象，并调用它的 draw 方法
Shape shape1 = shapeFactory.getShape("CIRCLE");
//调用 Circle 的 draw 方法
shape1.draw();
//获取 Rectangle 的对象，并调用它的 draw 方法
Shape shape2 = shapeFactory.getShape("RECTANGLE");
//调用 Rectangle 的 draw 方法
shape2.draw();
//获取 Square 的对象，并调用它的 draw 方法
Shape shape3 = shapeFactory.getShape("SQUARE");
//调用 Square 的 draw 方法
shape3.draw();
}
}
Inside Circle::draw() method. Inside Rectangle::draw() method. Inside Square::draw() method.
public class Subject {
private List<Observer> observers = new ArrayList<>();
private int state;
public int getState() {
return state;
}
public void setState(int state) {
this.state = state;
notifyAllObservers();
}
public void attach(Observer observer) {
observers.add(observer);
}
public void notifyAllObservers() {
for (Observer observer : observers) {
observer.update();
}
}
}
public abstract class Observer {
protected Subject subject;
public abstract void update();
}
public class BinaryObserver extends Observer {
public BinaryObserver(Subject subject) {
this.subject = subject;
this.subject.attach(this);
}
@Override
public void update() {
System.out.println("Binary String: "
Integer.toBinaryString(subject.getState()));
}
}
public class OctalObserver extends Observer {
public OctalObserver(Subject subject){
this.subject = subject;
this.subject.attach(this);
}
@Override
public void update() {
System.out.println( "Octal String: "
Integer.toOctalString( subject.getState() ) );
}
}
public class HexaObserver extends Observer {
public HexaObserver(Subject subject){
this.subject = subject;
this.subject.attach(this);
}
@Override
public void update() {
System.out.println( "Hex String: "
Integer.toHexString( subject.getState() ).toUpperCase() );
}
}
public class ObserverPatternDemo {
public static void main(String[] args) {
Subject subject = new Subject();
new BinaryObserver(subject);
new HexaObserver(subject);
new OctalObserver(subject);
System.out.println("First state change: 15");
subject.setState(15);
System.out.println();
System.out.println("Second state change: 10");
subject.setState(10);
}
}
First state change: 15 Binary String: 1111 Hex String: F Octal String: 17 Second state change: 10 Binary String: 1010 Hex String: A Octal String: 12
public interface Shape {
void draw();
}
public class Rectangle implements Shape {
@Override
public void draw() {
System.out.println("Shape: Rectangle");
}
}
public class Circle implements Shape {
@Override
public void draw() {
System.out.println("Shape: Circle");
}
}
public abstract class ShapeDecorator implements Shape {
protected Shape decoratorShape;
public ShapeDecorator(Shape decoratorShape) {
this.decoratorShape = decoratorShape;
}
@Override
public void draw() {
decoratorShape.draw();
}
}
public class RedShapeDecorator extends ShapeDecorator {
public RedShapeDecorator(Shape decoratorShape) {
super(decoratorShape);
}
@Override
public void draw() {
decoratorShape.draw();
setRedBorder(decoratorShape);
}
private void setRedBorder(Shape decoratorShape) {
System.out.println("Border Color: Red");
}
}
public class DecoratorPatternDemo {
public static void main(String[] args) {
Shape circle = new Circle();
Shape redCircle = new RedShapeDecorator(new Circle());
Shape redRectangle = new RedShapeDecorator(new Rectangle());
System.out.println("Circle with normal border");
circle.draw();
System.out.println("\nCircle of red border");
redCircle.draw();
System.out.println("\nRectangle of red border");
redRectangle.draw();
}
}
Circle with normal border Shape: Circle Circle of red border Shape: Circle Border Color: Red Rectangle of red border Shape: Rectangle Border Color: Red
public static void main(String[] args) {
int[] array = {3, 44, 38, 5, 47, 15, 36, 26, 27, 2, 46, 4, 19, 50, 48};
// 只需要修改成对应的方法名就可以了
bubbleSort(array);
System.out.println(Arrays.toString(array));
}
/**
* Description:冒泡排序
*
* @param array 需要排序的数组
* @author JourWon
* @date 2019/7/11 9:54
*/
public static void bubbleSort(int[] array) {
if (array == null || array.length <= 1) {
return;
}
int length = array.length;
// 外层循环控制比较轮数i
for (int i = 0; i < length; i ) {
// 内层循环控制每一轮比较次数，每进行一轮排序都会找出一个较大值
// (array.length - 1)防止索引越界，(array.length - 1 - i)减少比较次数
for (int j = 0; j < length - 1 - i; j ) {
// 前面的数大于后面的数就进行交换
if (array[j] > array[j 1]) {
int temp = array[j 1];
array[j 1] = array[j];
array[j] = temp;
}
}
}
}
public static void main(String[] args) {
int[] array = {3, 44, 38, 5, 47, 15, 36, 26, 27, 2, 46, 4, 19, 50, 48};
// 只需要修改成对应的方法名就可以了
selectionSort(array);
System.out.println(Arrays.toString(array));
}
/**
* Description: 选择排序
*
* @param array
* @return void
* @author JourWon
* @date 2019/7/11 23:31
*/
public static void selectionSort(int[] array) {
if (array == null || array.length <= 1) {
return;
}
int length = array.length;
for (int i = 0; i < length - 1; i ) {
// 保存最小数的索引
int minIndex = i;
for (int j = i 1; j < length; j ) {
// 找到最小的数
if (array[j] < array[minIndex]) {
minIndex = j;
}
}
// 交换元素位置
if (i != minIndex) {
swap(array, minIndex, i);
}
}
}
/**
* Description: 交换元素位置
*
* @param array
* @param a
* @param b
* @return void
* @author JourWon
* @date 2019/7/11 17:57
*/
private static void swap(int[] array, int a, int b) {
int temp = array[a];
array[a] = array[b];
array[b] = temp;
}
public static void main(String[] args) {
int[] array = {3, 44, 38, 5, 47, 15, 36, 26, 27, 2, 46, 4, 19, 50, 48};
// 只需要修改成对应的方法名就可以了
quickSort(array);
System.out.println(Arrays.toString(array));
}
/**
* Description: 快速排序
*
* @param array
* @return void
* @author JourWon
* @date 2019/7/11 23:39
*/
public static void quickSort(int[] array) {
quickSort(array, 0, array.length - 1);
}
private static void quickSort(int[] array, int left, int right) {
if (array == null || left >= right || array.length <= 1) {
return;
}
int mid = partition(array, left, right);
quickSort(array, left, mid);
quickSort(array, mid 1, right);
}
private static int partition(int[] array, int left, int right) {
int temp = array[left];
while (right > left) {
// 先判断基准数和后面的数依次比较
while (temp <= array[right] && left < right) {
--right;
}
// 当基准数大于了 arr[left]，则填坑
if (left < right) {
array[left] = array[right];
left;
}
// 现在是 arr[right] 需要填坑了
while (temp >= array[left] && left < right) {
left;
}
if (left < right) {
array[right] = array[left];
--right;
}
}
array[left] = temp;
return left;
}
public static Integer recursionMulity(Integer n) {
if (n == 1) {
return 1;
}
return n * recursionMulity(n - 1);
}
public static int fib(int mon) {
if (mon < 2) {
return 1;
} else {
return fib(mon - 1) fib(mon - 2);
}
}
public class BinarySearch {
public static void main(String[] args) {
int[] arr = {5, 12, 23, 43, 66, 98, 100};
System.out.println(binarySort(arr, 23));
}
/**
* 循环实现二分查找
*
* @param arr
* @param key
* @return
*/
public static int binarySearch(int[] arr, int key) {
//第一个下标
int low = 0;
//最后一个下标
int high = arr.length - 1;
int mid = 0;
//防越界
if (key < arr[low] || key > arr[high] || low > high) {
return -1;
}
while (low <= high) {
mid = (low high) >>> 1;
if (key < arr[mid]) {
high = mid - 1;
} else if (key > arr[mid]) {
low = mid 1;
} else {
return mid;
}
}
return -1;
}
}
public class ConsistentHash<T> {
/**
* 节点的复制因子,实际节点个数 * numberOfReplicas = 虚拟节点个数
*/
private final int numberOfReplicas;
/**
* 存储虚拟节点的hash值到真实节点的映射
*/
private final SortedMap<Integer, T> circle = new TreeMap<Integer, T>();
public ConsistentHash(int numberOfReplicas, Collection<T> nodes) {
this.numberOfReplicas = numberOfReplicas;
for (T node : nodes) {
add(node);
}
}
public void add(T node) {
for (int i = 0; i < numberOfReplicas; i ) {
// 对于一个实际机器节点 node, 对应 numberOfReplicas 个虚拟节点
/*
* 不同的虚拟节点(i不同)有不同的hash值,但都对应同一个实际机器node
* 虚拟node一般是均衡分布在环上的,数据存储在顺时针方向的虚拟node上
*/
String nodestr = node.toString() i;
int hashcode = nodestr.hashCode();
System.out.println("hashcode:" hashcode);
circle.put(hashcode, node);
}
}
public void remove(T node) {
for (int i = 0; i < numberOfReplicas; i ) {
circle.remove((node.toString() i).hashCode());
}
}
/**
* 获得一个最近的顺时针节点,根据给定的key 取Hash
* 然后再取得顺时针方向上最近的一个虚拟节点对应的实际节点
* 再从实际节点中取得 数据
*
* @param key
* @return
*/
public T get(Object key) {
if (circle.isEmpty()) {
return null;
}
// node 用String来表示,获得node在哈希环中的hashCode
int hash = key.hashCode();
System.out.println("hashcode----->:" hash);
//数据映射在两台虚拟机器所在环之间,就需要按顺时针方向寻找机器
if (!circle.containsKey(hash)) {
SortedMap<Integer, T> tailMap = circle.tailMap(hash);
hash = tailMap.isEmpty() ? circle.firstKey() : tailMap.firstKey();
}
return circle.get(hash);
}
public long getSize() {
return circle.size();
}
/**
* 查看表示整个哈希环中各个虚拟节点位置
*/
public void testBalance() {
//获得TreeMap中所有的Key
Set<Integer> sets = circle.keySet();
//将获得的Key集合排序
SortedSet<Integer> sortedSets = new TreeSet<Integer>(sets);
for (Integer hashCode : sortedSets) {
System.out.println(hashCode);
}
System.out.println("----each location 's distance are follows: ----");
/*
* 查看相邻两个hashCode的差值
*/
Iterator<Integer> it = sortedSets.iterator();
Iterator<Integer> it2 = sortedSets.iterator();
if (it2.hasNext()) {
it2.next();
}
long keyPre, keyAfter;
while (it.hasNext() && it2.hasNext()) {
keyPre = it.next();
keyAfter = it2.next();
System.out.println(keyAfter - keyPre);
}
}
public static void main(String[] args) {
Set<String> nodes = new HashSet<String>();
nodes.add("A");
nodes.add("B");
nodes.add("C");
ConsistentHash<String> consistentHash = new ConsistentHash<String>(2, nodes);
consistentHash.add("D");
System.out.println("hash circle size: " consistentHash.getSize());
System.out.println("location of each node are follows: ");
consistentHash.testBalance();
String node = consistentHash.get("apple");
System.out.println("node----------->:" node);
}
}
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