java并发:interrupt进程终止

interrupt进程终止

interrupt()源码

    /**
     * Interrupts this thread.
     *
     * <p> Unless the current thread is interrupting itself, which is
     * always permitted, the {@link #checkAccess() checkAccess} method
     * of this thread is invoked, which may cause a {@link
     * SecurityException} to be thrown.
     *
     * <p> If this thread is blocked in an invocation of the {@link
     * Object#wait() wait()}, {@link Object#wait(long) wait(long)}, or {@link
     * Object#wait(long, int) wait(long, int)} methods of the {@link Object}
     * class, or of the {@link #join()}, {@link #join(long)}, {@link
     * #join(long, int)}, {@link #sleep(long)}, or {@link #sleep(long, int)},
     * methods of this class, then its interrupt status will be cleared and it
     * will receive an {@link InterruptedException}.
     *
     * <p> If this thread is blocked in an I/O operation upon an {@link
     * java.nio.channels.InterruptibleChannel InterruptibleChannel}
     * then the channel will be closed, the thread's interrupt
     * status will be set, and the thread will receive a {@link
     * java.nio.channels.ClosedByInterruptException}.
     *
     * <p> If this thread is blocked in a {@link java.nio.channels.Selector}
     * then the thread's interrupt status will be set and it will return
     * immediately from the selection operation, possibly with a non-zero
     * value, just as if the selector's {@link
     * java.nio.channels.Selector#wakeup wakeup} method were invoked.
     *
     * <p> If none of the previous conditions hold then this thread's interrupt
     * status will be set. </p>
     *
     * <p> Interrupting a thread that is not alive need not have any effect.
     *
     * @throws  SecurityException
     *          if the current thread cannot modify this thread
     *
     * @revised 6.0
     * @spec JSR-51
     */
    public void interrupt() {
        if (this != Thread.currentThread())
            checkAccess();

        synchronized (blockerLock) {
            Interruptible b = blocker;
            if (b != null) {
                interrupt0();           // Just to set the interrupt flag
                b.interrupt(this);
                return;
            }
        }
        interrupt0();
    }

我主要强调一点当线程处于阻塞状态的时候，调用interrupt()，interrupt status 状态会被clear，从true再次变为false。所以对于通过InterruptedException异常

来中断需要正确的try catch语句。

正确的阻塞线程中断方式

package com.java.javabase.thread.base;

import lombok.extern.slf4j.Slf4j;

@Slf4j
public class InterruptTest2 {

    public static void main(String[] args) {
        InterruptTest2 test = new InterruptTest2();
        Thread t1 = test.new ThreadOne("t1");
        t1.start();

        try {
            Thread.sleep(2000);
            t1.interrupt();
            log.info("Thread t1 state :{} ", t1.getState());
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

    }

    class ThreadOne extends Thread {
        public ThreadOne(String name) {
            super(name);
        }

        @Override
        public void run() {
            int i = 0;

            try {
                while (!interrupted()) {
                    Thread.sleep(500);
                    log.info("Thread {}  state :{} ,run {} times", Thread.currentThread().getName(),
                            Thread.currentThread().getState(), i++);
                }
            } catch (InterruptedException e) {
                log.info("Thread {}  state :{} ,run {} times", Thread.currentThread().getName(),
                        Thread.currentThread().getState(), i++);
                e.printStackTrace();
            }
        }
    }
}

返回结果

2019-07-30 19:52:40,496   [t1] INFO  InterruptTest2  - Thread t1  state :RUNNABLE ,run 0 times
2019-07-30 19:52:41,000   [t1] INFO  InterruptTest2  - Thread t1  state :RUNNABLE ,run 1 times
2019-07-30 19:52:41,500   [t1] INFO  InterruptTest2  - Thread t1  state :RUNNABLE ,run 2 times
2019-07-30 19:52:41,991   [main] INFO  InterruptTest2  - Thread t1 state :TIMED_WAITING
2019-07-30 19:52:41,991   [t1] INFO  InterruptTest2  - Thread t1  state :RUNNABLE ,run 3 times
java.lang.InterruptedException: sleep interrupted
	at java.lang.Thread.sleep(Native Method)
	at com.java.javabase.thread.base.InterruptTest2$ThreadOne.run(InterruptTest2.java:36)

说明

while语句在try catch 捕获到InterruptedException异常，就可以处理。

错误的中断阻塞线程例子

package com.java.javabase.thread.base;

import lombok.extern.slf4j.Slf4j;

@Slf4j
public class InterruptTest {

    public static void main(String[] args) {
        InterruptTest test = new InterruptTest();
        Thread t1 = test.new ThreadOne("t1");
        t1.start();

        try {
            Thread.sleep(2000);
            t1.interrupt();
            log.info("Thread state :{} ", t1.getState());
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

    }

    class ThreadOne extends Thread {
        public ThreadOne(String name) {
            super(name);
        }

        @Override
        public void run() {
            int i = 0;
            while (!interrupted()) {
                try {
                    Thread.sleep(500);
                    log.info("Thread {}  state :{} ,run {} times", Thread.currentThread().getName(),
                            Thread.currentThread().getState(), i++);
                } catch (InterruptedException e) {
                    log.info("Thread {}  state :{} ,run {} times", Thread.currentThread().getName(),
                            Thread.currentThread().getState(), i++);
                    e.printStackTrace();
                }
            }
        }
    }
}

测试结果

2019-07-30 19:54:40,189   [t1] INFO  InterruptTest  - Thread t1  state :RUNNABLE ,run 0 times
2019-07-30 19:54:40,691   [t1] INFO  InterruptTest  - Thread t1  state :RUNNABLE ,run 1 times
2019-07-30 19:54:41,192   [t1] INFO  InterruptTest  - Thread t1  state :RUNNABLE ,run 2 times
2019-07-30 19:54:41,686   [t1] INFO  InterruptTest  - Thread t1  state :RUNNABLE ,run 3 times
2019-07-30 19:54:41,686   [main] INFO  InterruptTest  - Thread state :TIMED_WAITING
java.lang.InterruptedException: sleep interrupted
	at java.lang.Thread.sleep(Native Method)
	at com.java.javabase.thread.base.InterruptTest$ThreadOne.run(InterruptTest.java:35)
2019-07-30 19:54:42,187   [t1] INFO  InterruptTest  - Thread t1  state :RUNNABLE ,run 4 times
2019-07-30 19:54:42,687   [t1] INFO  InterruptTest  - Thread t1  state :RUNNABLE ,run 5 times
2019-07-30 19:54:43,187   [t1] INFO  InterruptTest  - Thread t1  state :RUNNABLE ,run 6 times
2019-07-30 19:54:43,687   [t1] INFO  InterruptTest  - Thread t1  state :RUNNABLE ,run 7 times
2019-07-30 19:54:44,187   [t1] INFO  InterruptTest  - Thread t1  state :RUNNABLE ,run 8 times
2019-07-30 19:54:44,687   [t1] INFO  InterruptTest  - Thread t1  state :RUNNABLE ,run 9 times
2019-07-30 19:54:45,187   [t1] INFO  InterruptTest  - Thread t1  state :RUNNABLE ,run 10 times

错误结果说明

try catch在while语句之内， 捕获到InterruptedException异常，while的!interrupted()会再次返回true

运行态的线程的终止

package com.java.javabase.thread.base;

import lombok.extern.slf4j.Slf4j;

@Slf4j
public class InterruptTest3 {
    private boolean stopFlag = false;

    private void stoptask() {
        this.stopFlag = true;
    }

    public static void main(String[] args) {
        InterruptTest3 test = new InterruptTest3();
        Thread t1 = test.new ThreadOne("t1");
        t1.start();

        try {
            Thread.sleep(5000);
            test.stoptask();
            log.info("Thread t1 state :{} ", t1.getState());
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

    }

    class ThreadOne extends Thread {
        public ThreadOne(String name) {
            super(name);
        }

        int i = 0;

        @Override
        public void run() {
            while (!stopFlag) {
                try {
                    sleep(1000);
                    log.info("Thread {}  state :{} ,run {} times", Thread.currentThread().getName(),
                            Thread.currentThread().getState(), i++);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

            }
        }
    }
}

测试结果

2019-07-30 20:01:19,922   [t1] INFO  InterruptTest3  - Thread t1  state :RUNNABLE ,run 0 times
2019-07-30 20:01:20,923   [t1] INFO  InterruptTest3  - Thread t1  state :RUNNABLE ,run 1 times
2019-07-30 20:01:21,923   [t1] INFO  InterruptTest3  - Thread t1  state :RUNNABLE ,run 2 times
2019-07-30 20:01:22,923   [t1] INFO  InterruptTest3  - Thread t1  state :RUNNABLE ,run 3 times
2019-07-30 20:01:23,918   [main] INFO  InterruptTest3  - Thread t1 state :TIMED_WAITING
2019-07-30 20:01:23,923   [t1] INFO  InterruptTest3  - Thread t1  state :RUNNABLE ,run 4 times