java 多线程编程

一.关于线程

• 线程是执行java程序代码的基本单位
• java线程是java平台的一部分

二.java中的线程编程

Thread类

java中的线程已被封装为Thread类，void start()方法就是启动线程的方法，调用后会让线程去执行指定的方法。void run()是其中一个方法，start()方法会把它作为线程的起点。

只要让一个类去继承Thread类，然后去覆盖其中的run()方法，那么就可以控制线程了

public class UseThread{
        public static void main(String[] args){
            MyThread thread = new MyThread();
            thread.run;
        }
}
class MyThread extends Thread{
    public void run(){
        System.out.println("This is a thread code");
    }
}

 可是一个类只能实现单继承，如果继承了线程类后，则无法继承其它类，于是这时候最好是使用接口。java提供了Runnable()接口，它包括了run()方法在内。Thread类中含有Runnable属性，构造方法可以是Thread(Runnable)，只要Runnable不为null，那么就可以启用run()方法。

public class UseThread {
　　　　public static void main(String[] args){
            MyRunnable runnable = new MyRunnable();
            Thread thread = new Thread(runnable);
            thread.run();
        }
}
class MyRunnable implements Runnable{
    public void run(){
        System.out.println("这是一个线程代码");
    }
}

package study_java;

public class Threadagain {
    public static void main(String[] args){
    Threadone threadone = new Threadone();
    Threadone threadtwo = new Threadone("线程1");
    
    
    threadtwo.start();
    threadone.start();
    threadone.printcurrentthread();
    threadtwo.printcurrentthread();
}
    
}
class Threadone extends Thread{
    Threadone(){
        super();
    }
    Threadone(String name){
        super(name);
    }
    public void run(){
        System.out.println("这个线程是： " + this.getName());
    }
    public void printcurrentthread(){
        Thread threading = Thread.currentThread();
        String threadingname = threading.getName();
        System.out.println(threadingname);
    }
}

package study_java;

public class Inner {
        public static void main(String[] args){
            PrintCurrentThread printer = new PrintCurrentThread();
            //匿名内部类
            Runnable runnable = new Runnable(){
                public void run(){
                    PrintCurrentThread p = new PrintCurrentThread();
                    p.printcurrrentthread();
                }
            };
            Thread thread = new Thread(runnable,"线程-1");
            thread.start();
            
            printer.printcurrrentthread();
        }
}
class PrintCurrentThread{
    public void printcurrrentthread(){
        Thread currentthread = Thread.currentThread();
        String threadname = currentthread.getName();
        System.out.println(threadname);
        
    }
}

package study_java;

public class Threadagain {
    public static void main(String[] args){
    Threadone threadone = new Threadone();
    Thread thread = new Thread( threadone);
    thread.start();
}
    
}
class Threadone implements Runnable{
    public void run(){
        System.out.println("这是一个我自己创建的线程");
    }
}

package study_java;

public class Threadagain {
    public static void main(String[] args){
    
    Thread thread = new Thread( new Runnable() {
        public void run(){
            System.out.println("这是一个我自己创建的线程");
        }
    });
    thread.start();
}
    
}
class Threadone implements Runnable{
    public void run(){
        System.out.println("这是一个我自己创建的线程");
    }
}

 使用匿名类