多线程

作者: 嘉美伯爵 | 来源:发表于2017-05-15 17:00 被阅读9次

    Thread类(须有start调用run才可启动线程)

    public void start()
    使该线程开始执行;Java 虚拟机调用该线程的 run 方法。
    结果是两个线程并发地运行;当前线程(从调用返回给 start 方法)和另一个线程(执行其 run 方法)。多次启动一个线程是非法的。特别是当线程已经结束执行后,不能再重新启动。

    
    class MyThread extends Thread{
        private String name;
        public MyThread(String name){
            this.name = name;
        }
        public void run(){
            for(int x=0;x<200;x++){
                System.out.println(name+"----->"+x);
            }
        }
    }
    public class Demo {
    
        public static void main(String[] args) {
            // TODO Auto-generated method stub
            MyThread m1 = new MyThread("Java");
            MyThread m2 = new MyThread("Javb");
            MyThread m3 = new MyThread("Javc");
            m1.run();
            m2.run();
            m3.run();
        }
    }
    

    多线程执行

    class MyThread extends Thread{
        private String name;
        public MyThread(String name){
            this.name = name;
        }
        public void run(){
            for(int x=0;x<200;x++){
                System.out.println(name+"----->"+x);
            }
        }
    }
    public class Demo {
        public static void main(String[] args) {
            // TODO Auto-generated method stub
            MyThread m1 = new MyThread("Java");
            MyThread m2 = new MyThread("Javb");
            MyThread m3 = new MyThread("Javc");
            m1.start();
            m2.start();
            m3.start();
        }
    }
    

    Runnable接口(由于单继承局限)

    public class Thread extends Object implements Runnable

    class MyThread implements Runnable{
        private String name;
        public MyThread(String name){
            this.name = name;
        }
        public void run(){
            for(int x=0;x<200;x++){
                System.out.println(name+"----->"+x);
            }
        }
    }
    public class Demo {
        public static void main(String[] args) {
            // TODO Auto-generated method stub
            MyThread m1 = new MyThread("Java");
            MyThread m2 = new MyThread("Javb");
            MyThread m3 = new MyThread("Javc");
            new Thread(m1).start();
            new Thread(m2).start();
            new Thread(m3).start();
        }
    }
    

    用Runnable实现主体类,用Thread启动线程

    Callable接口

    暂无
    

    线程的命名与取得

    构造方法:Thread(Runnable target, String name)
    public static Thread currentThread()此方法取得当前对象

    package Demo;
    //如果启动前未设置名字,则会自动编号命名
    class Mythread implements Runnable{
        @Override
        public void run() {
            // TODO Auto-generated method stub
            System.out.println(Thread.currentThread().getName());
        }
    }
    public class CollableDemo {
        public static void main(String[] args) {
            // TODO Auto-generated method stub
            Mythread mt = new Mythread();
            new Thread(mt).start();
            new Thread(mt).start();
            new Thread(mt).start();
        }
    }
    ------------------------------------
    Thread-0
    Thread-1
    Thread-2
    

    设置名字:public final void setName(String name)

    package Demo;
    
    class Mythread implements Runnable{
        @Override
        public void run() {
            // TODO Auto-generated method stub
            System.out.println(Thread.currentThread().getName());
        }
    }
    public class CollableDemo {
        public static void main(String[] args) {
            // TODO Auto-generated method stub
            Mythread mt = new Mythread();
            new Thread(mt,"线程A").start();
            new Thread(mt).start();
            new Thread(mt,"线程B").start();
            new Thread(mt).start();
        }
    
    }
    

    取得名字:public final String getName()

    package Demo;
    
    class Mythread implements Runnable{
        @Override
        public void run() {
            // TODO Auto-generated method stub
            System.out.println(Thread.currentThread().getName());
        }
    }
    public class CollableDemo {
    
        public static void main(String[] args) {
            // TODO Auto-generated method stub
            Mythread mt = new Mythread();
            new Thread(mt,"线程A").start();
            mt.run();
        }
    
    }
    --------------------------
    main
    线程A
    

    主方法就是一个线程(main线程),在子方法上创建的线程为子线程;main只是进程上的一个子线程。

    线程的休眠

    public static void sleep(long millis,int nanos) throws InterruptedException

    package Demo;
    
    class Mythread implements Runnable{
        @Override
        public void run() {
            // TODO Auto-generated method stub
            for(int x=0;x<1000;x++){
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName()+",x ="+x);
            }
        }
    }
    public class CollableDemo {
    
        public static void main(String[] args) throws Exception {
            // TODO Auto-generated method stub
            Mythread mt = new Mythread();
            new Thread(mt,"线程A").start();
        }
    }
    

    如果设置了多个线程对象,则一起进入run()方法

    package Demo;
    
    class Mythread implements Runnable{
        @Override
        public void run() {
            // TODO Auto-generated method stub
            for(int x=0;x<1000;x++){
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName()+",x ="+x);
            }
        }
    }
    public class CollableDemo {
    
        public static void main(String[] args) throws Exception {
            // TODO Auto-generated method stub
            Mythread mt = new Mythread();
            new Thread(mt,"线程A").start();
            new Thread(mt,"线程B").start();
            new Thread(mt,"线程C").start();
            new Thread(mt,"线程D").start();
            new Thread(mt,"线程E").start();
        }
    }
    ------------------------------------
    线程B,x =0
    线程A,x =0
    线程E,x =0
    线程D,x =0
    线程C,x =0
    线程C,x =1
    线程A,x =1
    线程B,x =1
    线程E,x =1
    线程D,x =1
    线程E,x =2
    线程C,x =2
    线程A,x =2
    线程D,x =2
    线程B,x =2
    线程E,x =3
    线程A,x =3
    线程C,x =3
    线程D,x =3
    线程B,x =3
    线程D,x =4
    线程E,x =4
    线程C,x =4
    线程A,x =4
    线程B,x =4
    

    线程优先级

    设置优先级:public final void setPriority(int newPriority)
    取得优先级:public final int getPriority()
    使用int返回,有三个优先级
    最高:public static final int MAX_PRIORITY 10
    中等:public static final int NORM_PRIORITY 5
    最低:public static final int MIN_PRIORITY 1

    package Demo;
    
    class Mythread implements Runnable{
        @Override
        public void run() {
            // TODO Auto-generated method stub
            for(int x=0;x<20;x++){
                try {
                    Thread.sleep(2000);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName()+",x ="+x);
            }
        }
    }
    public class CollableDemo {
    
        public static void main(String[] args) throws Exception {
            // TODO Auto-generated method stub
            Mythread mt = new Mythread();
            Thread t1 = new Thread(mt,"线程A");
            Thread t2 = new Thread(mt,"线程B");
            Thread t3 = new Thread(mt,"线程C");
            t3.setPriority(Thread.MAX_PRIORITY);
            t1.start();
            t2.start();
            t3.start();
        }
    }
    

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