Network Programming in Java

Java in the network programming is mainly Java socket programming, belongs to the advanced part of Java EE, the following is a summary of the programming of the network, the code is compiled debugging

c/S Program application: Client/server mode, such as QQ client, client connected to the server, a C/S mode application must have two sets of programs, one is the client's program, one is the server program.

b/S application: Browser/server mode, such as the current various sites are B/s mode, all the program code is on the server, the user through the browser to access.

The C/S program is divided into two types:

TCP-based protocol: socket (socket), reliable programming: A->b make a connection if you call first

Based on UDP protocol: unreliable, such as SMS function.

If you write a TCP program that requires two packages of Java support:

JAVA.NET.*: mainly provide network support;

|-serversocket class: Server-side programs

|-socket Class: Client program

java,io.*: Passing Information flow

Two features of the client:

1. Create a socket

2. Receive input commands (input stream)--the program that is transmitted over the network is a byte stream.

The following is the server side, the client's two case program, the server side wants the client output Hello Word, the client receives and displays;

Server program:

1 Import java.io.*; 2 Import java.net.*; 3 public class Tcpsever {4   5     /** 6      * @param args 7      * @throws IOException 8      */9 public     static Voi D main (string[] args) throws IOException {ten         //TODO auto-generated method STUB11         //Use ServerSocket12         ServerSocket Server = new ServerSocket (8000);         //Each user is a Socket15 Socket client in the program         = null;16  +//         waiting for client to connect to the customer         = Server.accept ();/         /Like client printing information         printwriter out = null;22  The         information is printed to the client on the         new PrintWriter (Client.getoutputstream ());         out.println ("Hello World"); 26         out.close ();         client.close ();         server.close ();     }30  31}

Client program:

1 package Client; 2 Import java.io.*; 3 Import java.net.*; 4   5 public class TCPClient {6   7     /** 8      * @param args 9      * @throws IOException10      * @throws Unknownho StException11      */12 public     static void Main (string[] args) throws Unknownhostexception, IOException {         // TODO auto-generated Method Stub14         //Represents a client's Socket15         Socket client = null;16 +/         /Indicates input information for a client 18         bufferedreader  buf = null;19         client = new Socket ("localhost", 8000),         buf = new BufferedReader ( New InputStreamReader (Client.getinputstream ()));         System.out.println (Buf.readline ());         Buf.close ();         client.close ();     }26  27}

Two classes dedicated to implementing UDP are also prepared in the JDK

1.DatagramScoket

2.DatagramPacket

Server-side programs:

Package Client;import Java.io.*;import java.net.*; public class TCPClient {     /**     * @param args     * @throws ioexception     * @throws unknownhostexception     */< C6/>public static void Main (string[] args) throws Unknownhostexception, IOException {        //TODO auto-generated Method St UB        //Indicates a client's socket        socket clients = NULL;         Represents the input information for a client        bufferedreader  buf = null;        Client = new Socket ("localhost", 8000);        BUF = new BufferedReader (New InputStreamReader (Client.getinputstream ()));        System.out.println (Buf.readline ());        Buf.close ();        Client.close ();     } }

Client program:

1 package Test4; 2 Import java.io.*; 3 Import java.net.*; 4 public class UdpClient {5   6     /** 7      * @param args 8      * @throws IOException 9      */10 public     static VO ID Main (string[] args) throws IOException {one         //TODO auto-generated method stub12         datagramsocket ds = null;13
   
    datagrampacket DP = null;14         byte[] b = new byte[1024];16         -ds = new Datagramsocket (8000); 18
    DP = new Datagrampacket (b,b.length),         ds.receive (DP),         string str = new String (Dp.getdata (), 0, Dp.getlength ());         System.out.println (str);     }23  24}
   

Network Programming in Java