我在尝试将文件从服务器发送到客户端时遇到了一些麻烦。我似乎无法将相同的文件从服务器发送到客户端到两个SEPERATE文件。相反，它只是附加到第一个文件的末尾！任何帮助将不胜感激。
编辑：我修改了代码。我已经将文件发送和接收任务模块化为2个函数'sendfile'和'recievefile'。我现在得到的错误是在第二次调用后套接字在sendfile和recievefile函数关闭。但我正在关闭的是文件，输出和输入流！也许关闭这些流也会关闭套接字......？无论如何，我试过不关闭输入和输出流，会发生什么 - 1）没有任何东西被转移到目标文件。所以我只是在服务器端获得一个空白的文件。 2）甚至没有创建第二个文件。大。
像往常一样，任何帮助都会受到赞赏。
服务器：
package com.http.server;
import java.io.*;
import java.net.*;
public class Server
{
public static void main(String args[])throws Exception
{
System.out.println("Server running...");
/* Listen on port 5555 */
ServerSocket server = new ServerSocket(5555);
/* Accept the sk */
Socket sk = server.accept();
System.out.println("Server accepted client");
BufferedReader inReader = new BufferedReader(new InputStreamReader(sk.getInputStream()));
BufferedWriter outReader = new BufferedWriter(new OutputStreamWriter(sk.getOutputStream()));
/* Read the filename */
String serverlocation = "C:/Users/Arjun/Desktop/CNW model/HTTP Website/";
String filename = serverlocation + inReader.readLine();
if ( !filename.equals("") ){
/* Reply back to client with READY status */
outReader.write("READY\n");
outReader.flush();
}
sendfile(sk, filename);
sendfile(sk, filename);
outReader.close();
inReader.close();
sk.close();
server.close();
}
public static void sendfile(Socket sk, String filename)
{
try{
OutputStream output = sk.getOutputStream();
FileInputStream file = new FileInputStream(filename);
byte[] buffer = new byte[sk.getSendBufferSize()];
int bytesRead = 0;
while((bytesRead = file.read(buffer))>0)
{
output.write(buffer,0,bytesRead);
}
file.close();
output.close();
}
catch (Exception ex){
System.out.println(ex);
}
}
}
客户端：
package com.http.client;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.io.*;
public class Client extends JFrame implements ActionListener {
/**
*
*/
private static final long serialVersionUID = 1L;
private JTextField txtFile;
public static void main(String args[]){
/* Create and display the client form */
Client clientForm = new Client();
clientForm.Display();
}
public void Display(){
JFrame frame = new JFrame();
frame.setTitle("Client");
FlowLayout layout = new FlowLayout();
layout.setAlignment(FlowLayout.LEFT);
JLabel lblFile = new JLabel("URL:");
txtFile = new JTextField();
txtFile.setPreferredSize(new Dimension(150,30));
JButton btnTransfer = new JButton("Get");
btnTransfer.addActionListener(this);
JPanel mainPanel = new JPanel();
mainPanel.setLayout(layout);
mainPanel.add(lblFile);
mainPanel.add(txtFile);
mainPanel.add(btnTransfer);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setVisible(true);
}
public void actionPerformed(ActionEvent e) {
/* File Open Dialog box allows the user to select a file */
String filename=txtFile.getText();
try{
/* Try to connect to the server on localhost, port 5555 */
Socket sk = new Socket("localhost", 5555);
/* Send filename to server */
OutputStreamWriter outreader = new OutputStreamWriter(sk.getOutputStream());
outreader.write(filename + "\n");
outreader.flush();
/* Get response from server */
BufferedReader inReader = new BufferedReader(new InputStreamReader(sk.getInputStream()));
String serverStatus = inReader.readLine(); // Read the first line
/* If server is ready, receive the file */
while ( !serverStatus.equals("READY") ){}
/* Create a new file in the tmp directory using the filename */
recievefile(sk,filename);
recievefile(sk,"xx"+filename);
JOptionPane.showMessageDialog(this, "Transfer complete");
inReader.close();
outreader.close();
sk.close();
}
catch (Exception ex){
/* Catch any errors */
JOptionPane.showMessageDialog(this, ex.getMessage());
System.out.println(ex);
}
}
public void recievefile(Socket sk, String filename)
{
try{
InputStream input = sk.getInputStream();
FileOutputStream wr = new FileOutputStream(new File("C:/tmp/" + new File(filename).getName()));
byte[] buffer = new byte[sk.getReceiveBufferSize()];
int bytesReceived = 0;
while((bytesReceived = input.read(buffer))>0)
{
/* Write to the file */
wr.write(buffer,0,bytesReceived);
}
wr.close();
input.close();
}
catch (Exception ex){
/* Catch any errors */
JOptionPane.showMessageDialog(this, ex.getMessage());
System.out.println(ex);
}
}
}
答案 0 :(得分：5)
当您发送文件时，您只需将一个文件附加到另一个文件的末尾，以便客户端看到它们。
您需要让客户知道何时停止阅读一个文件并开始阅读第二个文件。
最简单的方法是在文件之前发送文件的长度，并且只读取与数据量完全相同的数据。
顺便说一句：你不能以你的方式组合二进制和文本流。这更容易导致混淆。在你的情况下，你需要发送二进制文件，所以使用DataInputStream和DataOutputStream使一切二进制。
我想到的是类似的东西。
public static void sendFile(DataOutput out, String filename) throws IOException {
FileInputStream fis = new FileInputStream(filename);
byte[] bytes = new byte[8192];
try {
long size = fis.getChannel().size();
out.writeLong(size);
for (int len; (len = fis.read(bytes, 0, (int) Math.min(bytes.length, size))) > 0; ) {
out.write(bytes, 0, len);
size -= len;
}
assert size == 0;
} finally {
fis.close();
}
}
public void receiveFile(DataInput in, String filename) throws IOException {
long size = in.readLong();
FileOutputStream fos = new FileOutputStream(filename);
byte[] bytes = new byte[8192];
try {
for (int len; (len = (int) Math.min(size, bytes.length)) > 0; ) {
in.readFully(bytes, 0, len);
fos.write(bytes, 0, len);
size -= len;
}
} finally {
fos.close();
}
}