Java 多线程与锁

Posted 2020-08-12

多线程

线程和进程的区别

 

创建线程

• 通过实现Runnable 接口

 1 class RunnableDemo implements Runnable{
 2     private Thread t;   // create a thread 
 3     private String threadName;
 4 
 5     RunnableDemo(String name){
 6         threadName = name;
 7         System.out.println("Creating " + threadName);
 8         try{
 9             for(int i = 3; i > 0; i--){
10                 System.out.println("Thread: " + threadName + ", " + i);
11                 // wait for a while.
12                 Thread.sleep(50);
13             }
14         }catch (InterruptedException e){
15             System.out.println("Thread " + threadName +" interrupted");
16         }
17         System.out.println("Thread “ + threadName + " exiting.");
18     }  
19 
20
21     public void start(){
22         System.out.println("Starting ” + threadName);
23         if( t == null){
24             t = new Thread(this, threadName);
25             t.start();
26         }
27     }
28 
29 public class TestThread{
30     public static void main(String[] args){
31         RunnableDemo R1 = new RunnableDemo("Thread-1");
32         R1.start();
33 
34         RunnableDemo R2 = new RunnableDemo("Thread-2");
35         R2.start();
36      }
37 }

 　　When an object implementing interface Runnable is used to create a thread, starting the thread causes the object‘s run method to be called in that separately executing thread.

 

• 通过继承Thread类

class ThreadDemo extends Thread {
   private Thread t;
   private String threadName;
   
   ThreadDemo( String name) {
      threadName = name;
      System.out.println("Creating " +  threadName );
   }
   
   public void run() {
      System.out.println("Running " +  threadName );
      try {
         for(int i = 4; i > 0; i--) {
            System.out.println("Thread: " + threadName + ", " + i);
            // Let the thread sleep for a while.
            Thread.sleep(50);
         }
      }catch (InterruptedException e) {
         System.out.println("Thread " +  threadName + " interrupted.");
      }
      System.out.println("Thread " +  threadName + " exiting.");
   }
   
   public void start () {
      System.out.println("Starting " +  threadName );
      if (t == null) {
         t = new Thread (this, threadName);
         t.start ();
      }
   }
}

public class TestThread {

   public static void main(String args[]) {
      ThreadDemo T1 = new ThreadDemo( "Thread-1");
      T1.start();
      
      ThreadDemo T2 = new ThreadDemo( "Thread-2");
      T2.start();
   }   
}

 

 java.lang.Thread

public class Thread
extends Object
implements Runnable

　　

锁

同步

 

 

参考：

http://www.tutorialspoint.com/java/java_multithreading.htm

http://docs.oracle.com/javase/7/docs/api/java/lang/Runnable.html

https://docs.oracle.com/javase/7/docs/api/java/lang/Thread.html