java 多線程編程

一.關於線程

• 線程是執行java程序代碼的基本單位
• java線程是java平臺的一部分

二.java中的線程編程

Thread類

java中的線程已被封裝爲Thread類，void start()方法就是啓動線程的方法，調用後會讓線程去執行指定的方法。void run()是其中一個方法，start()方法會把它做爲線程的起點。

只要讓一個類去繼承Thread類，而後去覆蓋其中的run()方法，那麼就能夠控制線程了

 1 public class UseThread{
 2         public static void main(String[] args){
 3             MyThread thread = new MyThread();
 4             thread.run;
 5         }
 6 }
 7 class MyThread extends Thread{
 8     public void run(){
 9         System.out.println("This is a thread code");
10     }
11 }

 

 但是一個類只能實現單繼承，若是繼承了線程類後，則沒法繼承其它類，因而這時候最好是使用接口。java提供了Runnable()接口，它包括了run()方法在內。Thread類中含有Runnable屬性，構造方法能夠是Thread(Runnable)，只要Runnable不爲null，那麼就能夠啓用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("這是一個線程代碼");
    }
}

 

package study_java;

public class Threadagain {
    public static void main(String[] args){
    Threadone threadone = new Threadone();
    Threadone threadtwo = new Threadone("線程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("這個線程是： " + 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();
            //匿名內部類
            Runnable runnable = new Runnable(){
                public void run(){
                    PrintCurrentThread p = new PrintCurrentThread();
                    p.printcurrrentthread();
                }
            };
            Thread thread = new Thread(runnable,"線程-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("這是一個我本身建立的線程");
    }
}

 

 1 package study_java;
 2 
 3 public class Threadagain {
 4     public static void main(String[] args){
 5     
 6     Thread thread = new Thread( new Runnable() {
 7         public void run(){
 8             System.out.println("這是一個我本身建立的線程");
 9         }
10     });
11     thread.start();
12 }
13     
14 }
15 class Threadone implements Runnable{
16     public void run(){
17         System.out.println("這是一個我本身建立的線程");
18     }
19 }

 使用匿名類