FileUpload包下放了三个类：

OpenAndSave.java

TCPClient .java

TCPServer.java

1、OpenAndSave.java

package FileUpload;
import java.awt.*;
import javax.swing.*;
import java.util.*;
import java.io.*;
public class OpenAndSave extends JFrame {
	
	// 选择打开文件
	public String getFile() {
		String fileName="";
		FileDialog fd = new FileDialog(this, "请选择要传给zpc的文件", FileDialog.LOAD);
		fd.setDirectory("C:\\");
		fd.setVisible(true);
		// 获取此文件对话框选定的文件
		if (fd.getFile()!= null) {
			fileName=fd.getDirectory() + fd.getFile();
			System.out.println("已选择打开 " +fileName );
		}
		return fileName;
	}


	// 保存文件
	public OutputStream saveFile(String fileName) {
		OutputStream os=null;
		try {
			FileDialog fd = new FileDialog(this, "保存文件", FileDialog.SAVE);
			// 对话框打开时显示默认的目录
			fd.setDirectory("C:\\");
			fd.setFile(fileName);
			fd.setVisible(true);
			if (fd.getFile() != null) {
				File myFile = new File(fd.getDirectory(), fd.getFile());
				os = new FileOutputStream(myFile);
			}
		} catch (IOException ioe) {
			JOptionPane.showMessageDialog(this, "文件保存发生错误，已停止");
		}
		return os;
	}
}

2、TCPServer.java

/*
 * Author：zpc
 * Time:2014-5-1
 */
package FileUpload;
import java.io.*;
import java.net.*;
import java.util.Random;
import javax.swing.*;

//每接受一个客户端请求单开一个线程处理
class UploadProcess implements Runnable {
	private Socket s;

	public UploadProcess(Socket s) {
		this.s = s;
	}

	public void run() {
		OutputStream fos = null;
		try {
			DataInputStream fis = new DataInputStream(s.getInputStream());// 和复制文件不同的是网络上传文件是从Socket中获取的I/O流对象
			String fileName = fis.readUTF();
			DataOutputStream fos1= new DataOutputStream(s.getOutputStream());//写回信息;
			if ((JOptionPane.showOptionDialog(null,
					"您想接受文件" + fileName + "吗？", "消息",
					JOptionPane.YES_NO_OPTION, 0, null, null, null)) == 0) {
				System.out.println("我已选择接受文件！");
				String message1="服务器已接收！";
				fos1.writeUTF(message1);
				fos = new OpenAndSave().saveFile(fileName);
				int len = 0;
				byte[] bytes = new byte[1024];
				if (fis != null) {
					while ((len = fis.read(bytes)) != -1) {
						fos.write(bytes, 0, len);
					}
				}
				JOptionPane.showMessageDialog(null, "文件保存成功！");
				if (fis != null)
					fis.close();
				if (fos != null)
					fos.close();
			}
			else {
				System.out.println("我选择了拒绝接受！");
				String message2="提示：对方已拒绝接受！";
				fos1.writeUTF(message2);
			}
		} catch (Exception e) {
			System.out.println("接受文件失败！");
		}
	}
}

public class TCPServer {
	public static void main(String[] args) throws IOException {
		// 建立服务器端的socket对象ServerSocket
		ServerSocket ss = new ServerSocket(10001);
		while (true) {
			Socket s = ss.accept();
			// 每个客户端的请求创建一个Socket对象，单开一个线程处理
			new Thread(new UploadProcess(s)).start();
		}
	}
}

3、TCPClient .java

/*
 * Author:zpc
 * Function:上传文件给用户zpc
 * Time:2014-5-1
 */
package FileUpload;
import java.io.*;
import java.net.*;
public class TCPClient {
	public static void main(String[] args) throws UnknownHostException{
		// 进行文件的读取.数据源
		OpenAndSave open = new OpenAndSave();
		String fileName = open.getFile();
		File myFile = new File(fileName);
		InputStream in = null;
		try {
			in = new FileInputStream(myFile);
		} catch (FileNotFoundException e1) {
			System.out.println("未选中文件！");
		}
		// 数据目的地是另一台主机,通过Socket获取I/O流
		if (in != null) {
			Socket s = null;
			try {
				s = new Socket("127.0.0.1", 10001);//这里写好目标机器IP地址和任意一个开放的未被其它程序占用的端口号
				DataOutputStream os = new DataOutputStream(s.getOutputStream());
				os.writeUTF(fileName);
				byte[] b = new byte[1024];
				int len = 0;
				while ((len = in.read(b)) != -1) {
					os.write(b, 0, len);
				}
				//System.out.println("message");
				DataInputStream fis = new DataInputStream(s.getInputStream());
				String message = fis.readUTF();
				System.out.println(message);
				if (os != null)
					os.close();
				if (in != null)
					in.close();
			} catch (Exception e) {
				System.out.println("貌似zpc不在线,稍后再传！！");
			}
		} else {
			System.out.println("文件读取失败(in = null)！");
		}
	}
}