4个小例子看java线程挂起方法

本文代码都可在eclipse上直接运行

1.首先看个最简单的方法，也是你最容易理解的：suspend。（注意：已经废弃了，说是会导致死锁）

public class Thread1{

public static void main(String[] args) {

ThreadC c = new ThreadC();

c.start();

}

}

class ThreadC extends Thread{

public void run() {

ThreadB b = new ThreadB();

b.start();

System.out.println("c等待1开始");

try {

sleep(2000);

} catch (InterruptedException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

}

System.out.println("c等待1完成");

try {

b.suspend();

System.out.println("b.suspend()");

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

System.out.println("c等待2开始");

try {

sleep(2000);

} catch (InterruptedException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

}



System.out.println("c等待2完成");

b.resume();

System.out.println("c说：b对象计算的总和是：" + b.total);

}}

class ThreadB extends Thread {

int total;

public void run() {

for (int i = 0; i < 10; i++) {

total += i;

System.out.println("b说： 我查数"+i);

try {

sleep(500);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

}

2.再看另一个使用join的方法：

public class Thread1{

public static void main(String[] args) {

ThreadC c = new ThreadC();

c.start();

}

}

class ThreadC extends Thread{

public void run() {

ThreadB b = new ThreadB();



System.out.println("c等待1开始");

try {

sleep(2000);

} catch (InterruptedException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

}

System.out.println("c等待1完成");

try {

b.start();

b.join();

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

System.out.println("c等待2开始");

try {

sleep(2000);

} catch (InterruptedException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

}



System.out.println("c等待2完成");



System.out.println("b对象计算的总和是：" + b.total);

}}

class ThreadB extends Thread {

int total;

public void run() {

for (int i = 0; i < 10; i++) {

total += i;

System.out.println("我是b 我查数"+i);

try {

sleep(500);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}



}

}

3.现在学习wait和notify的使用，这需要配合synchronized 的使用。

让我们看看wait和notify是怎么释放和还回锁的：

public class Thread1{

public static void main(String[] args) {

ThreadC c = new ThreadC();

c.start();

}

}

class ThreadC extends Thread{

public void run() {

ThreadB b = new ThreadB();

Object theO=new Object();

b.setO(theO);

// 启动计算线程

b.start();



synchronized (theO) {//给这个代码块加锁

try {

System.out.println("c等待开始");

try {

sleep(1000);

} catch (InterruptedException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

}

System.out.println("c等待完成");



theO.wait();// 释放这个锁给另一个锁定的块，让另一个块执行



} catch (InterruptedException e) {

e.printStackTrace();

}

System.out.println("b对象计算的总和是：" + b.total);

}

}

}

class ThreadB extends Thread {

int total;

Object o;

public void setO(Object o)

{

this.o=o;

}

public void run() {

synchronized (o) {//我是另一个块，我开始不会执行，因为ThreadC里的锁定块先抢到了锁

for (int i = 0; i < 10; i++) {

total += i;

System.out.println("我是b 我查数"+i);

try {

sleep(500);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}



o.notify();//释放这个锁，给ThreadC继续执行

}

}

}

4.最后写一个使用wait和notify进行线程挂起的例子：

public class Thread1{

public static void main(String[] args) {

ThreadC c = new ThreadC();

c.start();

}

}

class ThreadC extends Thread{

public void run() {

ThreadB b = new ThreadB();

Object theO=new Object();

b.setO(theO);

b.start();

try {

System.out.println("c开始等500毫秒");

sleep(500);

} catch (InterruptedException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

}

synchronized (theO) {

try{

for (int i = 0; i < 6; i++) {

System.out.println("c查数： "+i);

sleep(500);

}

System.out.println("c notify这个对象，还锁");

theO.notify();



} catch (Exception e) {

e.printStackTrace();

}

}

}

}

class ThreadB extends Thread {

int total;

Object o;

public void setO(Object o)

{

this.o=o;

}

public void run() {

synchronized (o) {

for (int i = 0; i < 10; i++) {

total += i;

System.out.println("b 我查数"+i);

if(i==5)

try {

System.out.println("b wait 释放这个锁");

o.wait();

} catch (InterruptedException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

}

try {

sleep(500);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

}

}