Java基于Socket的文件传输实现方法

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IP
 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 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();
 }
}