Java通过Socket编程实现文件传输

客户端:

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:/";

/**
* @param args
*/
public static void main(String[] args) {

String fileName = "1.txt";
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：

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 = 8887; //port
public static final String IP = "127.0.0.1"; //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;
}

}