java socket编程收藏之一

(1)Server端

import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class Server{
	
	//ServerSocket监听的端口,等待客户连接请求，客户连接后，会话产生,在完成会话后，关闭连接。
    int port = 8821;

    void start() {
        Socket s = null;
        try {
        	//在连接成功时，应用程序两端都会产生一个Socket实例
            ServerSocket ss = new ServerSocket(port);
            while (true) {
            	
                String filePath = "D:/bars.jar";
                File fi = new File(filePath);

                //Accept方法用于产生"阻塞"，直到接受到一个连接，并且返回一个客户端的Socket对象实例
                System.out.println("Ready to accept task!");
                s = ss.accept();
                
                //s.getInputStream()获得网络连接输入，同时返回一个IutputStream对象实例
                DataInputStream dis = new DataInputStream(new BufferedInputStream(s.getInputStream()));
                dis.readByte();

                DataInputStream fis = new DataInputStream(new BufferedInputStream(new FileInputStream(filePath)));
                //s.getOutputStream()网络连接输出
                DataOutputStream ps = new DataOutputStream(s.getOutputStream());
                //将文件名及长度传给客户端。
                ps.writeUTF(fi.getName());
                ps.flush();
                ps.writeLong((long) fi.length());
                ps.flush();

                int bufferSize = 8192;
                byte[] buf = new byte[bufferSize];

                while (true) {
                    int read = 0;
                    if (fis != null) {
                        read = fis.read(buf);
                    }

                    if (read == -1) {
                        break;
                    }
                    ps.write(buf, 0, read);
                }
                ps.flush();
                fis.close();
                s.close(); //关闭socket               
                System.out.println("Task over!");
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void main(String arg[]) {
        new Server().start();
    }
}

(2)ClientSocket辅助类

import java.net.*;
import java.io.*;

public class ClientSocket {
    private String ip;

    private int port;

    private Socket socket = null;

    DataOutputStream out = null;

    DataInputStream getMessageStream = null;

    public ClientSocket(String ip, int port) {
        this.ip = ip;
        this.port = port;
    }

    /**
     * 创建socket连接
     * @throws Exception
     */
    public void CreateConnection() throws Exception {
        try {
            socket = new Socket(ip, port);
        } catch (Exception e) {
            e.printStackTrace();
            if (socket != null)
                socket.close();
            throw e;
        }
    }

    /**
     * 往Socket写数据
     * @param sendMessage
     * @throws Exception
     */
    public void sendMessage(String sendMessage) throws Exception {
        try {
            out = new DataOutputStream(socket.getOutputStream());
            if (sendMessage.equals("Windows")) {
                out.writeByte(0x1);
                out.flush();
                return;
            }else {
                out.writeUTF(sendMessage);
                out.flush();
            }
        } catch (Exception e) {
            e.printStackTrace();
            if (out != null)
                out.close();
            throw e;
        } 
    }

    /**
     * 从Socket读数据
     * @return
     * @throws Exception
     */
    public DataInputStream getMessageStream() throws Exception {
        try {
            getMessageStream = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
            return getMessageStream;
        } catch (Exception e) {
            e.printStackTrace();
            if (getMessageStream != null)
                getMessageStream.close();
            throw e;
        }
    }

    public void shutDownConnection() {
        try {
            if (out != null)
                out.close();
            if (getMessageStream != null)
                getMessageStream.close();
            if (socket != null)
                socket.close();
        } catch (Exception e) {

        }
    }
}

(3)客户端

import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.FileOutputStream;

public class ClientTest {
	//Socket对网络上某一个服务器的某一个端口发出连接请求
    private ClientSocket cs = null;

    private String ip = "localhost";

    private int port = 8821;

    private String sendMessage = "Windwos";

    public ClientTest() {
        try {
            if (createConnection()) {
                sendMessage();
                getMessage();
            }

        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    private boolean createConnection() {
        cs = new ClientSocket(ip, port);
        try {
            cs.CreateConnection();
            System.out.print("连接服务器成功!" + "\n");
            return true;
        } catch (Exception e) {
            System.out.print("连接服务器失败!" + "\n");
            return false;
        }

    }

    private void sendMessage() {
        if (cs == null)
            return;
        try {
            cs.sendMessage(sendMessage);
        } catch (Exception e) {
            System.out.print("发送消息失败!" + "\n");
        }
    }

    private void getMessage() {
        if (cs == null)
            return;
        DataInputStream inputStream = null;
        try {
            inputStream = cs.getMessageStream();
        } catch (Exception e) {
            System.out.print("接收消息缓存错误\n");
            return;
        }

        try {
            //本地保存路径，文件名会自动从服务器端继承而来。
            String savePath = "E:\\";
            int bufferSize = 8192;
            byte[] buf = new byte[bufferSize];
            int passedlen = 0;
            long len=0;
            
            savePath += inputStream.readUTF();
            DataOutputStream fileOut = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(savePath)));
            len = inputStream.readLong();
            
            System.out.println("文件的长度为:" + len + "\n");
            System.out.println("开始接收文件!" + "\n");
                    
            while (true) {
                int read = 0;
                if (inputStream != null) {
                    read = inputStream.read(buf);
                }
                passedlen += read;
                if (read == -1) {
                    break;
                }
                fileOut.write(buf, 0, read);
            }
            System.out.println("接收完成，文件存为" + savePath + "\n");

            fileOut.close();
        } catch (Exception e) {
            System.out.println("接收消息错误" + "\n");
            return;
        }
    }

    public static void main(String arg[]) {
        new ClientTest();
    }
}