一个基于Java Socket实现文件传输示例

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(); // 注重关闭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续而来。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，这里假如是打文件，//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(); }}