线程的状态(通过代码案例简单而深入的理解线程的状态)
文章目录
- 线程的生命周期/状态state
- 线程状态变化流程图
- 线程状态
- NEW
- 案例举例
- 控台输出
- RUNNABLE和RUNNING
- 案例举例
- 控台输出
- 备注说明
- TIMED_WAITING
- 案例举例
- 控台输出
- 备注说明
- WAITING
- 案例举例
- 控台输出
- 备注说明
- Blocked
- 案例举例
- 控台说明
- TERMINATED
线程的生命周期/状态state
线程状态变化流程图
线程状态
NEW
案例举例
package com.gaoxinfu.demo.jdk.rt.java.lang.thread.status;
/**
* @Description:
* @Author: gaoxinfu
* @Date: 2020-06-11 11:48
*/
public class NewStatus {
public static void main(String[] args) {
Thread thread=new Thread("thread-a");
System.out.println("当前线程状态 = "+thread.getState());
}
}
控台输出
当前线程状态 = NEW
Process finished with exit code 0
RUNNABLE和RUNNING
案例举例
创建一个带有线程处理逻辑的线程类StatusThreadDemo
package com.gaoxinfu.demo.jdk.rt.java.lang.thread.status;
import java.util.concurrent.TimeUnit;
/**
* @Description:
* @Author: gaoxinfu
* @Date: 2020-06-10 16:37
*/
public class StartStatus {
public static void main(String[] args) {
StatusThreadDemo thread=new StatusThreadDemo();
System.out.println("start前线程状态 = "+thread.getState());
thread.start();
System.out.println("start后线程状态 = "+thread.getState());
try {
thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("start后线程正在运行的状态 = "+thread.getState());
}
}
class StatusThreadDemo extends Thread{
@Override
public void run() {
for (int i=0;i<5;i++){
try {
TimeUnit.SECONDS.sleep(1);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("StatusThreadDemo i="+i);
}
}
}
控台输出
start前线程状态 = NEW
start后线程状态 = RUNNABLE
StatusThreadDemo i=0
StatusThreadDemo i=1
StatusThreadDemo i=2
StatusThreadDemo i=3
StatusThreadDemo i=4
Process finished with exit code 0
备注说明
1.这里注意下，start()方法调用成功之后，并不是立刻进行运行，而是状态由New转为Runnable状态
而后，由操作系统进行调度转为Running运行状态;
2.这里大家需要注意下：Running状态如果由于某种原因被阻塞(如sleep中)或者由于某些原因，指令无法运行，
那么状态也会转为Runnable,等待操作系统重新调度;
3.这里的操作系统的切换，实际上就是CPU在线程中的调度切换;
4.我们上面演示的“start后线程状态 =”不一定是RUNNABLE 也有可能刚好碰上代码在sleep 就是Timed Wating
TIMED_WAITING
主要是你在调用下面方法的时候，待了超时时间
join
sleep
wait
LockSupport.parkUnit
案例举例
package com.gaoxinfu.demo.jdk.rt.java.lang.thread.status;
import java.util.concurrent.TimeUnit;
/**
* @Description:
* @Author: gaoxinfu
* @Date: 2020-06-11 15:25
*/
public class TimedWaitingStatus {
public static void main(String[] args) {
Thread thread=new Thread(new TimedWaitingThreadDemo());
thread.start();
System.out.println("线程sleep中的当前状态 = "+thread.getState());
}
}
class TimedWaitingThreadDemo implements Runnable{
@Override
public void run() {
System.out.println("开始sleep(5s)方法的调用");
try {
TimeUnit.SECONDS.sleep(5);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("结束sleep(5s)方法的调用");
}
}
控台输出
Connected to the target VM, address: '127.0.0.1:65084', transport: 'socket'
开始sleep(5s)方法的调用
线程sleep中的当前状态 = TIMED_WAITING
结束sleep(5s)方法的调用
Disconnected from the target VM, address: '127.0.0.1:65084', transport: 'socket'
Process finished with exit code 0
备注说明
WAITING
join
wait
LockSupport.parkUnit
1.上面的方法调用的时候，不带超时时间
案例举例
package com.gaoxinfu.demo.jdk.rt.java.lang.thread.status;
import java.util.concurrent.TimeUnit;
/**
* @Description:
* @Author: gaoxinfu
* @Date: 2020-06-11 15:36
*/
public class WaitingStatus {
public static void main(String[] args) throws InterruptedException {
Thread thread1=new Thread(new WaitingThreadDemo(),"thread1");
thread1.start();
System.out.println(thread1.getState());
}
}
class WaitingThreadDemo implements Runnable{
@Override
public void run() {
try {
Thread.currentThread().join();
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("Hello 大家好，我是WaitingThreadDemo ="+Thread.currentThread().getName());
}
}
控台输出
WAITING
Process finished with exit code 130 (interrupted by signal 2: SIGINT)
备注说明
Blocked
1.Blocked阻塞状态是一种锁阻塞的状态；
如 synchronized的锁
案例举例
package com.gaoxinfu.demo.jdk.rt.java.lang.thread.status;
/**
* @Description:
* @Author: gaoxinfu
* @Date: 2020-06-11 16:04
*/
public class BlockedStatus {
public static void main(String[] args) {
Thread thread1=new Thread(new BlockedThreadDemo(),"thread1");
Thread thread2=new Thread(new BlockedThreadDemo(),"thread1");
thread1.start();
thread2.start();
System.out.println("thread1线程状态 = " +thread1.getState());
System.out.println("thread2线程状态 = " +thread2.getState());
}
}
class BlockedThreadDemo implements Runnable{
@Override
public void run() {
synchronized (this){
try {
System.out.println("当前线程名字 = "+Thread.currentThread().getName()+",开始锁定代码执行片段");
Thread.currentThread().sleep(5000);
System.out.println("当前线程名字 = "+Thread.currentThread().getName()+",结束锁定代码执行片段");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
控台说明
当前线程名字 = thread1,开始锁定代码执行片段
thread1线程状态 = TIMED_WAITING
thread2线程状态 = BLOCKED
当前线程名字 = thread1,开始锁定代码执行片段
当前线程名字 = thread1,结束锁定代码执行片段
当前线程名字 = thread1,结束锁定代码执行片段
Process finished with exit code 0
TERMINATED
1.线程终止状态,也就是线程任务结束时的一个状态