ServerSocket類的經常使用方法

1.accept：偵聽並接受此套接字的鏈接；此方法在鏈接傳入以前一直阻塞。

2.setSoTimeout(timeout)方法的做用時設置超時時間，經過指定超時timeout值啓用/禁用超時功能，以ms爲單位。

　　必須在進入阻塞前調用這個方法，才能生效，一旦超時，程序會觸發SocketTimeoutException異常；默認值是0即永遠等待。

 

Server.java

package com.company.s7;

import java.io.IOException;
import java.net.ServerSocket;

public class Server {
    public static void main(String[] args) {
        try {
            ServerSocket serverSocket=new ServerSocket(8000);
            System.out.println(serverSocket.getSoTimeout());
            serverSocket.setSoTimeout(4000);
            System.out.println(serverSocket.getSoTimeout());
            System.out.println();

            System.out.println("begin "+System.currentTimeMillis());
            serverSocket.accept();
            System.out.println(" end "+System.currentTimeMillis());
        }catch (IOException e){
            e.printStackTrace();
        }
    }
}

Client.java

package com.company.s7;

import java.io.IOException;
import java.net.Socket;

public class Client {
    public static void main(String[] args) {
        try {
            System.out.println("client begin "+System.currentTimeMillis());
            Socket socket=new Socket("localhost",8000);
            System.out.println("client end "+System.currentTimeMillis());
        }catch (IOException e){
            e.printStackTrace();
            System.out.println("catch "+System.currentTimeMillis());
        }
    }
}

 

backlog參數含義：

容許接受客戶端鏈接請求的個數。

若是隊列已滿，則拒接該鏈接。

blacklog參數若是小於等於0，則使用默認值50；

Server.java

package com.company.s71;

import javax.sound.midi.Soundbank;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {
    public static void main(String[] args) throws IOException, InterruptedException {
        ServerSocket serverSocket=new ServerSocket(8088,3);

        //sleep(5000)的做用是不讓ServerSocket調用accept()方法，
        //而是由客戶端Socket先發奇10個鏈接請求
        //而後在執行accept方法時只能接收3個鏈接
        Thread.sleep(5000);

        System.out.println("accept1 begin");
        Socket socket1=serverSocket.accept();
        System.out.println("accept1 end");

        System.out.println("accept2 begin");
        Socket socket2=serverSocket.accept();
        System.out.println("accept2 end");

        System.out.println("accept3 begin");
        Socket socket3=serverSocket.accept();
        System.out.println("accept3 end");

        System.out.println("accept4 begin");
        Socket socket4=serverSocket.accept();
        System.out.println("accept4 end");

        System.out.println("accept5 begin");
        Socket socket5=serverSocket.accept();
        System.out.println("accept5 end");

        socket1.close();
        socket2.close();
        socket3.close();
        socket4.close();
        socket5.close();

        serverSocket.close();
    }
}

Client.java

package com.company.s71;

import java.io.IOException;
import java.net.Socket;

public class Client {
    public static void main(String[] args) throws IOException {
        Socket socket1=new Socket("localhost",8088);
        Socket socket2=new Socket("localhost",8088);
        Socket socket3=new Socket("localhost",8088);
        Socket socket4=new Socket("localhost",8088);
      //  Socket socket5=new Socket("localhost",8088);

    }
}

先啓動server.java，而後快速的啓動client.java；

可是讓我很奇怪的是服務端啓動五秒以後，再啓動客戶端，反而能正確的執行；

若是由知道的人，請留言區告知，謝謝。