实现SignalHandler

kill命令常用信号(之后代码会用到)：HUP 1 终端断线

INT 2 中断(同 Ctrl + C)

QUIT 3 退出(同 Ctrl + \)

TERM 15 终止

KILL 9 强制终止

CONT 18 继续(与STOP相反， fg/bg命令)

STOP 19 暂停(同 Ctrl + Z)

SignalHandler实现类import sun.misc.Signal;

import sun.misc.SignalHandler;

public class KillHandler implements SignalHandler {

/**

* HUP 1 终端断线 INT 2 中断(同 Ctrl + C) QUIT 3 退出(同 Ctrl + \) TERM 15 终止 KILL 9

* 强制终止 CONT 18 继续(与STOP相反， fg/bg命令) STOP 19 暂停(同 Ctrl + Z)

*/

public static final String TERM_15 = "TERM";

public static final String QUIT_3 = "QUIT";

public void registerSignal(String signalName) {

Signal signal = new Signal(signalName);

Signal.handle(signal, this);

}

@Override

public void handle(Signal signal) {

if (signal.getName().equals(TERM_15)) {

TestThread.shutdownFlag = true;

System.out.println("shutdownFlag=true");

// System.exit(0);

} else if (signal.getName().equals(QUIT_3)) {

// TODO do something

}

}

}

main类public class TestThread {

public static boolean shutdownFlag = false;

public static void main(String[] args) {

KillHandler killHandler = new KillHandler();

killHandler.registerSignal(KillHandler.TERM_15);

int i = 0;

while (true) {

System.out.println(i);

try {

Thread.sleep(500);

} catch (InterruptedException e) {

e.printStackTrace();

}

i++;

if(shutdownFlag)break;

}

try {

System.out.println("main Thread sleep 5s");

Thread.sleep(1000*5);

} catch (InterruptedException e) {

e.printStackTrace();

}

System.out.println("main Thread exit");

}

}

应用

运行main类，执行kill xxx，java程序会先执行实现类的handle方法，然后main方法运行完，释放资源，程序关闭。

ps：main类执行完才能释放资源，像while(true)这种循环必须打断才能释放资源。