java类库中的多线程

JDK类库中的线程池
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分类： J2EE2012-10-16 12:44162人阅读评论(0)收藏举报

jdkexceptionhttp服务器bufferstringsocket





Executor接口表示线程池，它的executor(Runnabletask)方法用来执行Runnable类型的任务。Executor的子接口ExecutorService中声明了管理线程池的一些方法，比如用于关闭线程池的shutdown()方法等，Executors类中包含了一些静态方法，它们负责生成各种类型的线程池ExecutorService实例.



例子：简单http服务器（阻塞模式)





[java] view plaincopyprint?
01.package http; 
02. 
03.import java.io.FileInputStream; 
04.import java.io.IOException; 
05.import java.net.InetSocketAddress; 
06.import java.net.Socket; 
07.import java.nio.ByteBuffer; 
08.import java.nio.CharBuffer; 
09.import java.nio.channels.FileChannel; 
10.import java.nio.channels.ServerSocketChannel; 
11.import java.nio.channels.SocketChannel; 
12.import java.nio.charset.Charset; 
13.import java.util.concurrent.ExecutorService; 
14.import java.util.concurrent.Executors; 
15. 
16.public class SimpleHttpServer { 
17.    private int port=80; 
18.    private ServerSocketChannel serverSocketChannel=null; 
19.    private ExecutorService executorService; 
20.    private static final int POOL_MULTIPLE=4; 
21.    private Charset charset=Charset.forName("utf-8"); 
22.    public SimpleHttpServer() throws IOException{ 
23.        executorService =Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors()*POOL_MULTIPLE); 
24.        serverSocketChannel=ServerSocketChannel.open(); 
25.        serverSocketChannel.socket().setReuseAddress(true); 
26.        serverSocketChannel.socket().bind(new InetSocketAddress(port)); 
27.        System.out.println("服务器启动"); 
28.    } 
29.    public void service(){ 
30.        while(true){ 
31.            SocketChannel socketChannel=null; 
32.            try { 
33.                socketChannel=serverSocketChannel.accept(); 
34.                executorService.execute(new Handler(socketChannel)); 
35.            } catch (Exception e) { 
36.                e.printStackTrace(); 
37.            } 
38.        } 
39.    } 
40.    public static void main(String[] args) throws IOException { 
41.        new SimpleHttpServer().service(); 
42.    } 
43.    class Handler implements Runnable{ 
44.        private SocketChannel socketChannel; 
45.        public Handler(SocketChannel socketChannel){ 
46.            this.socketChannel=socketChannel; 
47.        } 
48.        public void run(){ 
49.            handle(socketChannel); 
50.        } 
51.        public void handle(SocketChannel socketChannel){ 
52.            try { 
53.                Socket socket=socketChannel.socket(); 
54.                System.out.println("received client's connection come from "+socket.getInetAddress()+":"+socket.getPort()); 
55.                ByteBuffer buffer=ByteBuffer.allocate(2048);//accept http request,assume the request's length less than 2048 
56.                socketChannel.read(buffer); 
57.                buffer.flip(); 
58.                String request=decode(buffer); 
59.                System.out.println(request); //print the http reqeust 
60.                //construct http response 
61.                StringBuffer sb=new StringBuffer("HTTP/1.1 200 OK\r\n"); 
62.                sb.append("Content-Type:text/html\r\n\r\n"); 
63.                socketChannel.write(encode(sb.toString())); 
64.                 
65.                FileInputStream in; 
66.                //get the http request's first line 
67.                String firstLineOfRequest=request.substring(0,request.indexOf("\r\n")); 
68.                if(firstLineOfRequest.indexOf("login.html")!=-1){ 
69.                    in=new FileInputStream("D:\\work\\workspace\\myjava\\src\\http\\login.html");                    
70.                }else{ 
71.                    in=new FileInputStream("D:\\work\\workspace\\myjava\\src\\http\\hello.html"); 
72.                } 
73.                FileChannel fileChannel=in.getChannel(); 
74.                fileChannel.transferTo(0, fileChannel.size(), socketChannel);//send response 
75.            } catch (Exception e) { 
76.                e.printStackTrace(); 
77.            }finally{ 
78.                try { 
79.                    if(socketChannel!=null){ 
80.                        socketChannel.close(); 
81.                    } 
82.                } catch (Exception e2) { 
83.                    e2.printStackTrace(); 
84.                } 
85.            } 
86.        } 
87.        public String decode(ByteBuffer buffer){ 
88.            CharBuffer charBuffer=charset.decode(buffer); 
89.            return charBuffer.toString(); 
90.        } 
91.        public ByteBuffer encode(String str){ 
92.            return charset.encode(str); 
93.        } 
94.    } 
95.}