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Java学习---多线程的学习

时间:2018-07-21 19:55:02      阅读:174      评论:0      收藏:0      [点我收藏+]

标签:客户   chat   一个   线程   []   output   tis   long   block   

基础知识

每个正在系统上运行的程序都是一个进程(process)。每个进程包含一到多个线程(thread)。进程也可能是整个程序或者是部分程序的动态执行。

线程是一组指令的集合,或者是程序的特殊段,它可以在程序里独立执行。也可以把它理解为代码运行的上下文。所以线程基本上是轻量级的进程,它负责在单个程序里执行多任务。

Java对多线程的支持是非常强大的,他屏蔽掉了许多的技术细节,让我们可以轻松的开发多线程的应用程序。Java里面有2个方法实现多线程,

1 继承 Thread类,比如
  class MyThread extends Thread {
    public void run() {
    // 这里写上线程的内容
    }
    public static void main(String[] args) {
      // 使用这个方法启动一个线程
      new MyThread().start();
    }
  }
  2 实现 Runnable接口,例如
  class MyThread implements Runnable{
    public void run() {
    // 这里写上线程的内容
    }
    public static void main(String[] args) {
      // 使用这个方法启动一个线程
      new Thread(new MyThread()).start();
    }
  }
一般鼓励使用第二种方法,因为Java里面只允许单一继承,但允许实现多个接口。第二个方法更加灵活。

代码示例

多线程实现130的累计,其中共享资源池为130的数字的递增,采用了同步锁synchronized 

技术分享图片
 1 class Sum{ //共享资源,计数器count
 2     private int count;//共享资源
 3     public int add(){
 4         synchronized(this){ //代码段1,共享锁,修饰程序段或者方法
 5             count = count + 1;
 6             System.out.println("add:" + count);
 7             return count;            
 8         }
 9     }
10 }
11 class SumThread implements Runnable{//定义线程
12     private Sum sd;
13     private int sum = 0;
14     private    int [] a = new int[10];
15     
16     public SumThread(String name, Sum sd){
17         super(name);
18         this.sd = sd;
19     }
20     public void run(){//必需的重写
21         try{
22             for(int i=0;i<10;i++){
23                 a[i] = sd.add();
24                 sum += a[i];
25                 Thread.sleep(100);
26             }
27             Thread.sleep(1000);
28         }catch(Exception e){}
29         
30         System.out.println(getName() + "累加和:" + sum);
31     }
32     public void showData(){
33         System.out.print(getName() + "获得的数为");
34         for(int i=0;i<10;i++){
35             if(i%10==0)System.out.println();
36             System.out.print(a[i] + "+\t");
37         }
38     }
39     public int getSum(){
40         return sum;
41     }
42 }
43 public class SumDemo{
44     public static void main(String [] args){
45         Sum sd = new Sum();//代表共享资源的变量
46         SumThread s1 = new SumThread("线程1",sd);//创建完毕
47         SumThread s2 = new SumThread("线程2",sd);
48         SumThread s3 = new SumThread("线程3",sd);
49         Thread st1 = new Thread(s1);
50         Thread st2 = new Thread(s2);
51         Thread st3 = new Thread(s3);
52         st1.setPriority(Thread.MAX_PRIORITY);  //代码段2
53         st2.setPriority(10);
54         st3.setPriority(1);
55          long begin = System.currentTimeMillis();
56         st1.start();//使线程运行
57         st2.start();        st3.start();
58         St1.join();  st2.join();  st3.join();
59         st1.showData();
60         st2.showData();
61         st3.showData();
62         System.out.println("总和为:" + (st1.getSum() + st2.getSum() + st3.getSum())); 
63          long end = System.currentTimeMillis(); 
64          System.out.println(“探测localhost的TCP端口,共耗时” + 
65             ( end - begin)+"毫秒");
66 }  }
View Code

 TCP Socket多线程通信

服务端: 

技术分享图片
 1 import java.io.*;
 2 import java.net.*;
 3 import java.util.*;
 4 @SuppressWarnings(value={"deprecation","unchecked"}) //查阅该语句作用
 5 public class MultiServer extends Thread{
 6     ServerSocket serverSocket = null;
 7     boolean listening = true;
 8     int port = 1080;
 9     int count;
10     public MultiServer(){
11         try{
12             serverSocket = new ServerSocket(port);
13             System.out.println("The Chat Server is listening on " + port);
14         }catch(IOException e){
15             System.err.println("Can‘t listen on Port");
16             System.exit(1);
17         }
18         count = 0;
19         while(listening){
20             try{
21                 new ClientServiceThread(serverSocket.accept()).start();
22                 count += 1;
23                 System.out.println("The Chat Server get " + count + " Clients");
24             }catch(IOException e){
25                 System.err.println("Can‘t Accept the Client Connection Apply");
26             }
27         }        
28         try{
29             serverSocket.close();
30         }catch(IOException e){
31             System.exit(1);
32         }
33         this.start();
34     }    
35     public static void main(String args[]){
36         MultiServer ms = new MultiServer();
37 } }
View Code

 客户端:

技术分享图片
 1 class ClientServiceThread extends Thread{
 2     private String name = "Client";
 3     private Socket socket = null;
 4     private Vector clients = null;
 5     public ClientServiceThread(Socket socket){
 6         super("ClientServiceThread");
 7         this.socket = socket;
 8     }
 9     public ClientServiceThread(Vector clients, Socket socket){
10         super("ClientServiceThread");
11         this.socket = socket;
12         this.clients = clients;
13     }
14     public void run(){
15         try{
16             DataInputStream in = new DataInputStream(new
17           BufferedInputStream(socket.getInputStream()));
18             PrintStream out = new PrintStream(new 
19             BufferedOutputStream(socket.getOutputStream(), 1024), true);
20             
21             String inputLine, outputLine;
22             
23             GreetingProtocol greeting = new GreetingProtocol();
24             outputLine = greeting.processInput(null);
25             
26             out.println("Welcome to My Chat Server,    Please REG your Name, Format: name = yourname");
27             out.flush();
28         
29             while((inputLine = in.readLine()) != null){
30                 System.out.println(this.name + " Say: " + inputLine);
31                 if(inputLine.startsWith("name")){
32                     this.name = 
33 inputLine.substring(inputLine.indexOf("=") + 1);
34                     out.println("Your Name "+ this.name + " is REG");
35                     out.flush();
36                 }else{
37                     outputLine = greeting.processInput(inputLine);
38                     out.println(outputLine);
39                     out.flush();
40                 }
41                 if(inputLine.equals("bye")) break;
42             }
43             out.close();
44             in.close();
45             socket.close();
46         }catch(IOException e){
47             e.printStackTrace();
48 } } }
View Code

 

Java学习---多线程的学习

标签:客户   chat   一个   线程   []   output   tis   long   block   

原文地址:https://www.cnblogs.com/ftl1012/p/9347677.html

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