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update 设计模式
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‎src/main/java/com/chen/algorithm/sort/BubbleSort.java‎

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import org.junit.Test;
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/**
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* 冒泡排序算法
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* 冒泡排序算法 O(n平方)
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* Created by Chen Weijie on 2017/8/17.
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*/
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public class BubbleSort {

‎src/main/java/com/chen/api/util/base/StringTest.java‎

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package com.chen.api.util.base;
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/**
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* created by zhubaobao on 2017-09-11
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*/
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public class StringTest {
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static final int MAX = 100000;
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static final String[] arr = new String[MAX];
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public static void main(String[] args) {
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//1. 测试i++等，可通过反编译验证（http://blog.csdn.net/u013256816/article/details/50778902）
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// plus();
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//2.1 测试String类的intern()方法 （http://blog.csdn.net/seu_calvin/article/details/52291082）
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// String str2="SEUCalvin";//新加的一行代码，其余不变
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// String str1=new String("SEU")+new String("Calvin");
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// System.out.println(str1.intern() == str2);
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// System.out.println(str1=="SEUCalvin");
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// System.out.println("你好打分三大件佛奥qdqwadsdas1214@#$%^&*(".hashCode());
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//2.2 验证String类的intern方法的特点：节省空间，但是耗费时间
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// 为长度为10的Integer数组随机赋值
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// Integer[] sample = new Integer[10];
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// Random random = new Random(1000);
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// for (int i = 0; i < sample.length; i++) {
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// sample[i] = random.nextInt();
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// }
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// //记录程序开始时间
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// long t = System.currentTimeMillis();
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// //使用/不使用intern方法为10万个String赋值，值来自于Integer数组的10个数
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// for (int i = 0; i < MAX; i++) {
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// arr[i] = new String(String.valueOf(sample[i % sample.length]));
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//// arr[i] = new String(String.valueOf(sample[i %
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// sample.length])).intern();
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// }
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// System.out.println((System.currentTimeMillis() - t) + "ms");
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// System.gc();
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//2.3 测试intern方法的内存结构
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// String s = new String("1");
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// s.intern();
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// String s2 = "1";
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// System.out.println(s == s2);
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// String s3 = new String("1") + new String("1");
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// s3.intern();
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// String s4 = "11";
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// System.out.println(s3 == s4);
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//3. 测试StringBuilder和StringBuffer中的reverse方法
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// StringBuffer 和 StringBuilder
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// 类有reverse()方法，它们其实是调用的父类AbstractStringBuilder的reverse()方法
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StringBuffer sBuffer = new StringBuffer("abcD890dfg");
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System.out.println(sBuffer.reverse());
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// 4. 如何计算指定字符在字符串里出现的次数
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// 同样是使用Apache Commons Lang的StringUtils，如下：
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//int n = StringUtils.countMatches("aaaabbbb", "a");
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//Systemm.out.println(n);
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//判断String 创建了几个对象，用反编译验证
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String s = "a" + new String("123");// 创建了几个对象
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}
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static void plus() {
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int i = 0;
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int y = i++ + ++i;
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System.out.println(String.valueOf(y));
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}
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}

‎src/main/java/com/chen/api/util/jvm/javacAndjvm‎

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一、javac.exe、 java.exe、 java虚拟机三者之间的区别与联系:
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JDK中
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javac：Java编译器，将Java源代码换成字节代；
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java：Java解释器，直接从类文件执行Java应用程序代码；
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先编译 *.java文件――――>*.class文件
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运行 *.class ――加载――> JVM
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jvm加载二进制文件
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javac编译后得到的class文件是二进制指令，但不是机器指令，而是java虚拟机可识别的指令。这样class文件就有了可移植行。你可以把class文件拿到windows、linux或者solaris等不同的系统上去，在jvm上执行。
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java是启动jvm，jvm负责对class文件的内容进行处理，将字节码文件解释或者编译为机器指令，执行。

‎src/main/java/com/chen/api/util/lock/SyncThread.java‎

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package com.chen.api.util.lock;
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/**
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* @Author chenweijie
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* @Date 2017/9/17 1:39
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*/
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public class SyncThread implements Runnable {
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private Object obj1;
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private Object obj2;
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public SyncThread(Object o1, Object o2) {
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this.obj1 = o1;
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this.obj2 = o2;
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}
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@Override
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public void run() {
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String name = Thread.currentThread().getName();
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System.out.println(name + " acquiring lock on " + obj1);
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synchronized (obj1) {
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System.out.println(name + " acquiring lock on " + obj1);
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work();
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System.out.println(name + " acquiring lock on " + obj2);
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synchronized (obj2) {
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System.out.println(name + " acquiring lock on " + obj2);
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work();
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}
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System.out.println(name + " acquiring lock on " + obj2);
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}
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System.out.println(name + " released lock on " + obj1);
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System.out.println(name + " finished execution.");
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}
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private void work() {
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try {
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Thread.sleep(1000);
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} catch (InterruptedException e) {
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e.printStackTrace();
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}
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}
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}

‎src/main/java/com/chen/api/util/lock/ThreadDeadlock.java‎

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package com.chen.api.util.lock;
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/**
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* 死锁范例
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*
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* @Author chenweijie
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* @Date 2017/9/17 1:33
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*/
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public class ThreadDeadlock {
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public static void main(String[] args) throws InterruptedException {
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Object obj1 = new Object();
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Object obj2 = new Object();
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Object obj3 = new Object();
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Thread t1 = new Thread(new SyncThread(obj1, obj2), "t1");
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Thread t2 = new Thread(new SyncThread(obj1, obj3), "t2");
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Thread t3 = new Thread(new SyncThread(obj2, obj3), "t3");
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t1.start();
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Thread.sleep(5000);
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t2.start();
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Thread.sleep(5000);
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t3.start();
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}
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}

‎src/main/java/com/chen/api/util/syncthread/SynchronizedThread.java‎

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package com.chen.api.util.syncthread;
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/**
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* 线程同步的运用
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*
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* @Author chenweijie
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* @Date 2017/9/17 2:56
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*/
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public class SynchronizedThread {
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class Bank {
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private int account = 100;
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public int getAccount() {
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return account;
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}
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/**
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* 用同步方法实现
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*
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* @param money
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*/
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public synchronized void save(int money) {
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account += money;
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}
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/**
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* 用同步代码块实现
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*
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* @param money
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*/
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public void save1(int money) {
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synchronized (this) {
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account += money;
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}
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}
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}
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class NewThread implements Runnable {
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private Bank bank;
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public NewThread(Bank bank) {
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this.bank = bank;
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}
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@Override
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public void run() {
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for (int i = 0; i < 10; i++) {
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bank.save1(10);
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// bank.save(10);
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System.out.println(i + "账户余额为：" + bank.getAccount());
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}
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}
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}
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/**
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* 建立线程，调用内部类
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*/
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public void useThread() {
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Bank bank = new Bank();
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NewThread new_thread = new NewThread(bank);
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System.out.println("线程1");
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Thread thread1 = new Thread(new_thread);
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thread1.start();
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System.out.println("线程2");
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Thread thread2 = new Thread(new_thread);
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thread2.start();
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}
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public static void main(String[] args) {
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SynchronizedThread st = new SynchronizedThread();
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st.useThread();
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}
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}
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‎src/main/java/com/chen/api/util/thread/IncDecThread.java‎

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package com.chen.api.util.thread;
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/**
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* @Author chenweijie
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* @Date 2017/9/18 23:45
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*/
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public class IncDecThread {
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private int j = 10;
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/*
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* 题目:用JAVA写一个多线程程序，写四个线程，其中二个对一个变量加1，另外二个对一个变量减1
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* 两个问题：
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* 1、线程同步--synchronized
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* 2、线程之间如何共享同一个j变量--内部类
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*/
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public static void main(String[] args) {
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IncDecThread incDecThread = new IncDecThread();
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Inc inc = incDecThread.new Inc();
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Dec dec = incDecThread.new Dec();
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for (int i = 0; i < 2; i++) {
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Thread thread = new Thread(inc);
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thread.start();
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thread = new Thread(dec);
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thread.start();
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}
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}
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public synchronized void inc() {
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j++;
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System.out.println(Thread.currentThread().getName() + "-inc:" + j);
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}
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public synchronized void dec() {
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j--;
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System.out.println(Thread.currentThread().getName() + "-dec:" + j);
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}
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class Inc implements Runnable {
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@Override
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public void run() {
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for (int i = 0; i < 20; i++) {
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inc();
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}
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}
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}
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class Dec implements Runnable {
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@Override
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public void run() {
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for (int i = 0; i < 20; i++) {
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dec();
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}
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}
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}
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}

‎src/main/java/com/chen/api/util/thread/ReaderWriterList.java‎

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package com.chen.api.util.thread;
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import java.util.ArrayList;
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import java.util.Collections;
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import java.util.concurrent.locks.ReentrantReadWriteLock;
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/**
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* @Author chenweijie
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* @Date 2017/9/20 23:19
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*/
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public class ReaderWriterList<T> {
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private ArrayList<T> lockedList;
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private ReentrantReadWriteLock lock =new ReentrantReadWriteLock(true);
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public ReaderWriterList(int size,T initialValue){
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lockedList =new ArrayList<T>(Collections.nCopies(size,initialValue));
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}
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}

‎src/main/java/com/chen/api/util/thread/threadPool/ThreadPool.java‎

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package com.chen.api.util.thread.threadPool;
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import java.util.concurrent.ExecutorService;
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import java.util.concurrent.Executors;
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/**
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* @Author chenweijie
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* @Date 2017/9/17 23:34
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*/
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public class ThreadPool {
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public static void main(String[] args) {
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ExecutorService service =Executors.newSingleThreadExecutor();
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ExecutorService service2 = Executors.newCachedThreadPool();
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ExecutorService service3 =Executors.newFixedThreadPool(10);
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// new ThreadPoolExecutor(1,1,1,1,1);
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}
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}

‎src/main/java/com/chen/designPattern/singleton/Singleton1.java‎

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package com.chen.designPattern.singleton;
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import java.util.concurrent.atomic.AtomicInteger;
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/**
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* 懒汉式单例模式
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* Created by chenwj3 on 2017/2/28.
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public static Singleton1 getSingleton1() {
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AtomicInteger integer =new AtomicInteger();
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if (singleton1 == null) {
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singleton1 = new Singleton1();
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}

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