Java基于Socket文件传输示例 --- (http://www.blogjava.net/sterning/archive/2007/10/13/152508.html)

最近需要进行网络传输大文件，于是对基于socket的文件传输作了一个初步的了解。在一位网友提供的程序基础上，俺进行了一些加工，采用了缓冲输入/输出流来包装输出流，再采用数据输入/输出输出流进行包装，加快传输的速度。废话少说，先来看服务器端的程序。

1.服务器端

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();

}

}

2.socket的Util辅助类

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) {

}

}

}

3.客户端

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 = "Windows";

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得到。

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();

}

}

这就实现了从服务器端向客户端发送文件的过程,当然,反过来,也一样.稍有不同.代码中对跨平台的细节没有实现,有时间或兴趣的朋友可以提供一下.