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java创建线程方式

程序员文章站 2023-09-28 22:11:39
1.继承Thread类 public class ThreadCreator extends Thread{ public static void main(String[] args) { //第一种方式: ThreadCreator creator = new ThreadCreator(); ......

1.继承thread类

public class threadcreator extends thread{

    public static void main(string[] args) {
//第一种方式: threadcreator creator = new threadcreator(); thread thread = new thread(creator,"线程1");
thread.start();
//第二种方式:
thread thread = new threadcreator();
thread.start();
//第三种方式:
new threadcreator().start();
   } @override public void run() { system.out.println(thread.currentthread().getname() + "run"); } }

 

2.实现runnable接口

public class threadcreator implements runnable{

    public static void main(string[] args) {
       threadcreator creator = new threadcreator();
       thread thread = new thread(creator,"线程1");
       thread.start();
    }

    @override
    public void run() {
        system.out.println(thread.currentthread().getname() + "run");
    }
}

3.实现callable接口

public class threadcreator implements callable<integer> {

    public static void main(string[] args) throws executionexception, interruptedexception {
       threadcreator creator = new threadcreator();
       futuretask futuretask = new futuretask(creator);
       thread thread = new thread(futuretask,"线程");
       thread.start();
       system.out.println(futuretask.get());
    }

    @override
    public integer call() {
        return 1024;
    }
}

4.线程池executorservice

public class threadcreator{

   static executorservice service = executors.newfixedthreadpool(5);

    public static void main(string[] args) throws executionexception, interruptedexception {
        //execute无返回值
        service.execute(new threadtask(1,"1"));
        //submit有返回值
        future<integer> result = service.submit(new threadtaskcall());
        system.out.println(result.get());
service.shutdownnow(); } static class threadtask implements runnable{ private int param1; private string param2; public threadtask(int param3,string param4){ this.param1 = param3; this.param2 = param4; } @override public void run() { system.out.println(param1+param2); } } static class threadtaskcall implements callable<integer>{ @override public integer call() throws exception { return 1024; } } }

线程池中submit和execute的区别:

     ① 可接受的任务类型不一样:execute只能接受runnable任务,submit还可以接受callable任务。

     ② 返回值:execute无返回值,任务一旦提交,无法在当前线程中监控执行结果。submit有一个future类型的返回值,用来接收返回值或响应异常。通过get()方法获取。

submit底层还是调用的execute,只是在此基础上用future封装了一层,并将执行过程中产生的异常全部封装在一个变量中:

public void run() {
        if (state != new ||
            !unsafe.compareandswapobject(this, runneroffset,
                                         null, thread.currentthread()))
            return;
        try {
            callable<v> c = callable;
            if (c != null && state == new) {
                v result;
                boolean ran;
                try {
                    result = c.call();
                    ran = true;
                } catch (throwable ex) {
                    result = null;
                    ran = false;
                    setexception(ex);
                }
                if (ran)
                    set(result);
            }
        } finally {
            runner = null;
            int s = state;
            if (s >= interrupting)
                handlepossiblecancellationinterrupt(s);
        }
    }
protected void setexception(throwable t) {
        if (unsafe.compareandswapint(this, stateoffset, new, completing)) {
            outcome = t;
            unsafe.putorderedint(this, stateoffset, exceptional); // final state
            finishcompletion();
        }
    }

另外,spring中的schedule注解借鉴使用了submit的处理方式。

5.匿名内部类

public class threadcreator {

    public static void main(string[] args) {

        //继承thread类
        new thread() {
            @override
            public void run() {
                system.out.println("extends thread class!");
            }
        }.start();
        //实现runnable接口
        new thread(new runnable() {
            @override
            public void run() {
                system.out.println("implement runnable!");
            }
        }).start();
        //实现callable接口
        new thread(new futuretask<integer>(new callable() {
            @override
            public integer call() throws exception {
                return 1024;
            }
        })).start();
        //lambda表达式
        new thread(() -> system.out.println("execute single code")).start();
        new thread(() -> {
            system.out.println("execute multiple code");
        }).start();
    }
}

lambda线程池:

public class threadcreator {

    static executorservice service = executors.newfixedthreadpool(5);

    static list list = new arraylist();

    public static void main(string[] args) {
        service.execute(() -> execute()); //无返回值
        future future = service.submit(() -> execute()); //有返回值
        list.add(future);
    }

    public static void execute() {
        //do something
    }
}