package sterning;

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 ServerTest {
    int port = 8821;

    void start() {
        Socket s = null;
        try {
            ServerSocket ss = new ServerSocket(port);
            while (true) {
                // 选择进行传输的文件
                String filePath = "D:\\lib.rar";
                File fi = new File(filePath);

                System.out.println("文件长度:" + (int) fi.length());

                // public Socket accept() throws
                // IOException侦听并接受到此套接字的连接。此方法在进行连接之前一直阻塞。

                s = ss.accept();
                System.out.println("建立socket链接");
                DataInputStream dis = new DataInputStream(new BufferedInputStream(s.getInputStream()));
                dis.readByte();

                DataInputStream fis = new DataInputStream(new BufferedInputStream(new FileInputStream(filePath)));
                DataOutputStream ps = new DataOutputStream(s.getOutputStream());
                //将文件名及长度传给客户端。这里要真正适用所有平台，例如中文名的处理，还需要加工，具体可以参见Think In Java 4th里有现成的代码。
                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();
                // 注意关闭socket链接哦，不然客户端会等待server的数据过来，
                // 直到socket超时，导致数据不完整。                
                fis.close();
                s.close();                
                System.out.println("文件传输完成");
            }

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

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

package sterning;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*             exception*/public void CreateConnection() throws Exception {try {socket = new Socket(ip, port);} catch (Exception e) {e.printStackTrace();if (socket != null)socket.close();throw e;} finally {}}public void sendMessage(String sendMessage) throws Exception {try {out = new DataOutputStream(socket.getOutputStream());if (sendMessage.equals("Windows")) {out.writeByte(0x1);out.flush();return;}if (sendMessage.equals("Unix")) {out.writeByte(0x2);out.flush();return;}if (sendMessage.equals("Linux")) {out.writeByte(0x3);out.flush();} else {out.writeUTF(sendMessage);out.flush();}} catch (Exception e) {e.printStackTrace();if (out != null)out.close();throw e;} finally {}}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;} finally {}}public void shutDownConnection() {try {if (out != null)out.close();if (getMessageStream != null)getMessageStream.close();if (socket != null)socket.close();} catch (Exception e) {}}
}

package sterning;import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.FileOutputStream;public class ClientTest {private ClientSocket cs = null;private String ip = "localhost";// 设置成服务器IPprivate 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 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;}//下面进度条本为图形界面的prograssBar做的，这里如果是打文件，可能会重复打印出一些相同的百分比System.out.println("文件接收了" +  (passedlen * 100/ len) + "%\n");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();}
}