java中有三种停止线程方法
1)使用退出标志，使线程正常退出，也就是当run方法完成后线程终止。
2）使用stop方法方法强行终止线程，但是不推荐使用这个方法，应为stop不安全而且已经被废弃的方法，还有suspend和resume都是废弃的方法。
3）使用interrupt方法中断线程。
讲解第三种interrupt()方法 仅仅使房钱线程中打了一个停止的标记，并不是真的停止线程。代码如下：
public class MyThread extends Thread {
@Override
public void run() {
super.run();
for (int i = 0; i < 500000; i++) {
System.out.println("i=" + (i + 1));
}
}
}
public class Run {
public static void main(String[] args) {
try {
MyThread thread = new MyThread();
thread.start();
Thread.sleep(2000);
thread.interrupt();
} catch (InterruptedException e) {
System.out.println("main catch");
e.printStackTrace();
}
}
}
线程没有停止，而是打印完i
再分析下线程是否是停止的状态
this.interrupted() 测试当前线程是否已经中断。
this.isInterrupted()测试线程是否已经中断。
两者区别：（小白还是不懂，如果大神们知道还请您给我留个言解答下☺）
如下代码展示：
public class MyThread extends Thread {
@Override
public void run() {
super.run();
for (int i = 0; i < 50000; i++) {
System.out.println("i=" + (i + 1));
}
}
}
public class Run {
public static void main(String[] args) {
try {
MyThread thread = new MyThread();
thread.start();
Thread.sleep(1000);
thread.interrupt();
//Thread.currentThread().interrupt();
System.out.println(thread.getName()+ " 是否停止1？="+thread.interrupted());
System.out.println(thread.getName()+ " 是否停止2？="+thread.interrupted());
} catch (InterruptedException e) {
System.out.println("main catch");
e.printStackTrace();
}
System.out.println("end!");
}
public class Run2 {
public static void main(String[] args) {
System.out.println(Thread.currentThread().getName());
Thread.currentThread().interrupt();
System.out.println("是否停止1？=" + Thread.interrupted());
System.out.println("是否停止2？=" + Thread.interrupted());
System.out.println("end!");
}
}
public class Run3 {
public static void main(String[] args) {
try {
MyThread thread = new MyThread();
thread.start();
Thread.sleep(1000);
thread.interrupt();
System.out.println("是否停止1？="+thread.isInterrupted());
System.out.println("是否停止2？="+thread.isInterrupted());
} catch (InterruptedException e) {
System.out.println("main catch");
e.printStackTrace();
}
System.out.println("end!");
}
}
结果图：
1：停止线程（异常法）
public class MyThread extends Thread {
@Override
public void run() {
super.run();
for (int i = 0; i < 500000; i++) {
if (this.interrupted()) {
System.out.println("已经是停止状态了!我要退出了!");
break;
}
System.out.println("i=" + (i + 1));
}
}
}
public class Run {
public static void main(String[] args) {
try {
MyThread thread = new MyThread();
thread.start();
thread.sleep(2000);//线程睡2s 停止
// Thread.sleep(2000);
thread.interrupt();
} catch (InterruptedException e) {
System.out.println("main catch");
e.printStackTrace();
}
System.out.println("end!");
}
}
上面的代码会出现下面问题：并没有真正的退出线程
public class MyThread extends Thread {
@Override
public void run() {
super.run();
for (int i = 0; i < 500000; i++) {
if (this.interrupted()) {
System.out.println("已经是停止状态了!我要退出了!");
break;
}
System.out.println("i=" + (i + 1));
}
System.out.println("我被输出，如果此代码是for又继续运行，线程并未停止！");
}
}
public class Run {
public static void main(String[] args) {
try {
MyThread thread = new MyThread();
thread.start();
Thread.sleep(2000);
thread.interrupt();
} catch (InterruptedException e) {
System.out.println("main catch");
e.printStackTrace();
}
System.out.println("end!");
}
}
解决如下
public class MyThread extends Thread {
@Override
public void run() {
super.run();
try {
for (int i = 0; i < 500000; i++) {
if (this.interrupted()) {
System.out.println("已经是停止状态了!我要退出了!");
throw new InterruptedException();//中断异常
}
System.out.println("i=" + (i + 1));
}
System.out.println("我在for下面");
} catch (InterruptedException e) {
System.out.println("进MyThread.java类run方法中的catch了！");
e.printStackTrace();
}
}
}
public class Run {
public static void main(String[] args) {
try {
MyThread thread = new MyThread();
thread.start();
Thread.sleep(2000);
thread.interrupt();
} catch (InterruptedException e) {
System.out.println("main catch");
e.printStackTrace();
}
System.out.println("end!");
}
}
2：在沉睡中停止线程
public class MyThread extends Thread {
@Override
public void run() {
super.run();
try {
System.out.println("run begin");
Thread.sleep(200000);
System.out.println("run end");
} catch (InterruptedException e) {
System.out.println("在沉睡中被停止!进入catch!"+this.isInterrupted());
e.printStackTrace();
}
}
}
public class Run {
public static void main(String[] args) {
try {
MyThread thread = new MyThread();
thread.start();
Thread.sleep(200);
thread.interrupt();
} catch (InterruptedException e) {
System.out.println("main catch");
e.printStackTrace();
}
System.out.println("end!");
}
}
下面是先停止线程 再遇到sleep进入catch
public class MyThread extends Thread {
@Override
public void run() {
super.run();
try {
for(int i=0;i<100000;i++){
System.out.println("i="+(i+1));
}
System.out.println("run begin");
Thread.sleep(20000);
System.out.println("run end");
} catch (InterruptedException e) {
System.out.println("先停止，再遇到了sleep!进入catch!");
e.printStackTrace();
}
}
}
public class Run {
public static void main(String[] args) {
MyThread thread = new MyThread();
thread.start();
thread.interrupt();
System.out.println("end!");
}
}
3：使用stop()暴力停止线程。。会释放当前对象持有的锁
public class SynchronizedObject {
private String username = "a";
private String password = "aa";
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
//注意这里加同步方法 但是由于使用了stop方法 是对象释放锁
synchronized public void printString(String username, String password) {
try {
this.username = username;
Thread.sleep(100000);
this.password = password;
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public class MyThread extends Thread {
private SynchronizedObject object;
public MyThread(SynchronizedObject object) {
super();
this.object = object;
}
@Override
public void run() {
object.printString("b", "bb");
}
}
public class Run {
public static void main(String[] args) {
try {
SynchronizedObject object = new SynchronizedObject();
MyThread thread = new MyThread(object);
thread.start();
Thread.sleep(500);
thread.stop();
System.out.println(object.getUsername() + " "
+ object.getPassword());
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}打印如下
