多线程核心知识总结
四.线程生命周期
线程的六种状态
- New
已创建但还未启动的新线程
- Runnable
可运行的，调用start方法之后就会变成Runnable状态，无论是否运行，对应操作系统中的ready和running
- Blocked
当一个线程进入被sychornized修饰的代码块的时候，并且该锁已经被其他线程拿走了，这个时候的状态为Blocked
- Waiting
没有设置time参数的Object.wait（）等方法执行后，（具体看图）。
- Timed Waiting
Thread.sleep(time),Object.wait(time),Thread.join(time)等，（具体看图）
- Terminated
执行完成后进入的状态。
New , Runnable , Treminated 的代码演示：
public class NewRunnableTerminated implements Runnable {
public static void main(String
[] args
) {
Thread thread
= new Thread(new NewRunnableTerminated());
System
.out
.println(thread
.getState());
thread
.start();
System
.out
.println(thread
.getState());
try {
Thread
.sleep(10);
} catch (InterruptedException e
) {
e
.printStackTrace();
}
System
.out
.println(thread
.getState());
try {
Thread
.sleep(1000);
} catch (InterruptedException e
) {
e
.printStackTrace();
}
System
.out
.println(thread
.getState());
}
@Override
public void run() {
for (int i
= 0; i
< 1000; i
++) {
System
.out
.println(i
);
}
}
}
Blocked ,Waiting,TimedWaiting 的代码演示：
public class BlockedWaitingTimedWaiting implements Runnable{
public static void main(String
[] args
) {
BlockedWaitingTimedWaiting runnable
= new BlockedWaitingTimedWaiting();
Thread thread1
= new Thread(runnable
);
thread1
.start();
Thread thread2
= new Thread(runnable
);
thread2
.start();
try {
Thread
.sleep(5);
} catch (InterruptedException e
) {
e
.printStackTrace();
}
System
.out
.println(thread1
.getState());
System
.out
.println(thread2
.getState());
try {
Thread
.sleep(1300);
} catch (InterruptedException e
) {
e
.printStackTrace();
}
System
.out
.println(thread1
.getState());
}
@Override
public void run() {
syn();
}
private synchronized void syn() {
try {
Thread
.sleep(1000);
wait();
} catch (InterruptedException e
) {
e
.printStackTrace();
}
}
}
阻塞的定义
一般习惯而言，把Blocked(被阻塞），Waiting（等待），Timed_waiting（计时等待）都称为阻塞状态,不仅仅是Blocked
常见面试问题
线程有哪几种状态，线程的生命周期是什么？
直接按图理解：
