Java线程重复执行以及操作共享变量的代码示例

package com.Thread.test;/* * function:主线程执行10次，子线程执行10次， * 此过程重复50次 */public class ThreadProblem { public ThreadProblem() {  final Business bus = new Business(); new Thread(new Runnable() {    public void run() {    for(int j=0;j<50;j++) {      bus.sub(j);  }  } }).start();  for(int j=0;j<50;j++) {    bus.main(j); } } class Business {  private boolean tag=true; public synchronized void sub(int num) {    if(!tag) {    try {   this.wait();  } catch (InterruptedException e) {   // TODO Auto-generated catch block   e.printStackTrace();  }  }  for(int i=0;i<10;i++)  {  System.out.println("sub thread "+i+",loop "+num+".");  }    tag=false;  notify(); }  public synchronized void main(int num) {    if(tag) {    try {   this.wait();  } catch (InterruptedException e) {   // TODO Auto-generated catch block   e.printStackTrace();  }  }  for(int i=0;i<10;i++) {    System.out.println("main thread "+i+",loop "+num+".");  }    tag=true;  notify(); } }  public static void main(String[] args) {  ThreadProblem problem = new ThreadProblem(); }}

package com.Thread.test;//实现4个线程，两个线程加1，两个线程减1public class Demo1 { private static int j=0; private A a = new A(); //构造函数 public Demo1() {  System.out.println("j的初始值为:"+j); for(int i=0;i<2;i++) {    new Thread(new Runnable(){    public void run() {      for(int k=0;k<5;k++){   a.add1();   }  }  }).start();    new Thread(new Runnable(){    public void run() {       for(int k=0;k<5;k++)    {   a.delete1();    }  }  }).start(); } } class A {  public synchronized void add1() {    j++;  System.out.println(Thread.currentThread().getName()+"对j加1，目前j="+Demo1.j); }     public synchronized void delete1() {    j--;  System.out.println(Thread.currentThread().getName()+"对j减1，目前j="+Demo1.j); } }  //用于测试的主函数 public static void main(String[] args) {  Demo1 demo = new Demo1(); }}