Java通过Socket编程实现文件传输

通过Socket编程，实现把某个文件从客户端传到服务器端。

代码实现的功能：

文件位置--D:/Java/workspace/TCPSocketFileTransfer/ContestAppletProd.jnlp

客户端通过socket编程，把这个文件传送到服务器端

服务器把接收到的内容保存到D:/Java/workspace/TCPSocketFileTransfer/ContestAppletProd-2.jnlp中

客户端会首先传输文件名，之后时文件内容。

客户端代码：TCPClientSocket.java

package com.yt.socket;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.Socket;
import java.net.UnknownHostException;

public class TCPClientSocket {

	public static final String fileDir = "D:/Java/workspace/TCPSocketFileTransfer/";
	
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
		String fileName = "ContestAppletProd.jnlp";
		String filePath = fileDir + fileName;
		System.out.println("send filePath = " + filePath);
		
		Socket socket = null;
		
		try {
			socket = new Socket(TCPServerSocket.IP, TCPServerSocket.PORT);
			if(socket != null){
				System.out.println("Connection succcessed !");
				
				sendFile(socket, filePath);
			}
			
		} catch (UnknownHostException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	private static void sendFile(Socket socket, String filePath){
		DataOutputStream dos = null;
		BufferedInputStream bis = null; //What can BufferedInputStream help ? 
//		FileInputStream fis = null;
		byte[] bytes = new byte[1024];
		
		try {
			try {
				/*
				 * new a File with the filePath
				 * new a FileInputStream with the File to read the file by byte
				 * new a BufferedInputStream with the FileInputStream to use buffered stream
				 */
				bis = new BufferedInputStream(new FileInputStream(new File(filePath)));
				dos = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream()));
				
				
				//首先发送文件名     客户端发送使用writeUTF方法，服务器端应该使用readUTF方法
				dos.writeUTF(getFileName(filePath));
				
				//之后再发送文件的内容
				int length = 0;
				while((length = bis.read(bytes, 0, bytes.length)) > 0){
					dos.write(bytes, 0, length);
					dos.flush();
				}
				
				
			} catch (IOException e) {
				e.printStackTrace();
			} finally {
				//使用完毕后，应关闭输入、输出流和socket
				if(bis != null) bis.close();
				if(dos != null) dos.close();
				if(socket != null) socket.close();
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
		
	}
	
	/*
	 * example:
	 * filePath = "D:/Java/workspace/TCPSocketFileTransfer/Java_TCPIP_Socket.pdf"
	 * return "Java_TCPIP_Socket.pdf"
	 */
	private static String getFileName(String filePath){
		String[] parts = filePath.split("/");
		return parts[parts.length - 1];
	}

}

服务器端代码：TCPServerSocket.java

package com.yt.socket;

import java.io.DataInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.Socket;
import java.net.ServerSocket;

public class TCPServerSocket {

	public static final int PORT = 8888;				//port
	public static final String IP = "192.168.1.107"; 	//my ip address

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		ServerSocket mServerSocket = null;
		Socket socket = null;
		try {
			//创建服务器端
			mServerSocket = new ServerSocket(PORT);
			System.out.println("Server is already created now ! Waiting for client to connect ...");

			//客户端连接服务器端	
			socket = mServerSocket.accept();
			System.out.println("One client connected to this server successfully !");

			//连接成功，开始传输文件
			receiveFile(socket);

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

	private static void receiveFile(Socket socket) {

		FileOutputStream fos = null;
		DataInputStream dis = null;
		
		//buffer起缓冲作用，一次读取或写入多个字节的数据
		byte[] buffer = new byte[1024];

		try {
			try {
				//这里使用DataInputStream，可以调用它的readUTF方法来读取要传输的文件名，客户端使用writeUTF方法将文件名先传输过来
				dis = new DataInputStream(socket.getInputStream());
				
				//首先读取文件名
				String oldFileName = dis.readUTF();
				//文件路径采用与客户端相同的路径，文件名重新命名
				String filePath = TCPClientSocket.fileDir + genereateFileName(oldFileName);
				System.out.println("receive filePath = " + filePath);
				
				//利用FileOutputStream来操作文件输出流
				fos = new FileOutputStream(new File(filePath));
				
				int length = 0;
				
				/*
				 * length = dis.read(buffer, 0, buffer.length) 一次读入1024个字节的内容到buffer中，length代表实际读入的字节数
				 * fos.write(buffer, 0, length) 一次从buffer中的length个字节的内容写入到文件中 
				 * （注：文件大小超过1024B时，length一般为1024，最后一次读取可能小于1024）
				 */
				while((length = dis.read(buffer, 0, buffer.length)) > 0){
					fos.write(buffer, 0, length);
					fos.flush();
				}
				
			} finally {
				//使用完毕后，应关闭输入、输出流和socket
				if(dis != null) dis.close();
				if(fos != null)	fos.close();
				if(socket != null) socket.close();
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	/*
	 * example :
	 * oldName = "Java_TCPIP_Socket.pdf"
	 * newName = "Java_TCPIP_Socket-2.pdf"
	 */
	private static String genereateFileName(String oldName){
		String newName = null;
		newName = oldName.substring(0, oldName.lastIndexOf(".")) + "-2" + oldName.substring(oldName.lastIndexOf("."));
		return newName;
	}

}