这是一项任务。
我正在寻找一些关于我在哪里出错的建议。我的目标是从文件中读取文本，将其发送到服务器并将该文本写入新文件。
问题是我不确定如何做到这一点，我看了很多例子，但没有一点帮助。
按原样解释该程序。将要求用户输入与该代码的if statemnt相关的代码。我想关注的是代码200，它是服务器代码的上传文件。
当我运行代码时，我得到以下错误。有人可以向我解释我哪里出错了，我会很感激。
Connection request made
Enter Code: 100 = Login, 200 = Upload, 400 = Logout:
200
java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(Unknown Source)
at java.net.SocketInputStream.read(Unknown Source)
at sun.nio.cs.StreamDecoder.readBytes(Unknown Source)
at sun.nio.cs.StreamDecoder.implRead(Unknown Source)
at sun.nio.cs.StreamDecoder.read(Unknown Source)
at java.io.InputStreamReader.read(Unknown Source)
at java.io.BufferedReader.fill(Unknown Source)
at java.io.BufferedReader.readLine(Unknown Source)
at java.io.BufferedReader.readLine(Unknown Source)
at MyStreamSocket.receiveMessage(MyStreamSocket.java:50)
at EchoClientHelper2.getEcho(EchoClientHelper2.java:34)
at EchoClient2.main(EchoClient2.java:99)
服务器上出现此错误：
Waiting for a connection.
connection accepted
message received: 200
java.net.SocketException: Socket is not connected
at java.net.Socket.getInputStream(Unknown Source)
at EchoServer2.main(EchoServer2.java:71)
答案 0 :(得分：3)
您的MyStreamSocket类不需要扩展Socket。神秘的错误消息是因为MyStreamSocket表示的Socket永远不会连接到任何东西。其socket成员引用的Socket是连接的Socket。因此，当您从MyStreamSocket获取输入流时，它真的没有连接。这会导致错误，这意味着客户端会关闭。这导致套接字关闭，服务器正式报告
BufferedReader的使用会给你带来麻烦。它总是尽可能多地读入缓冲区，因此在文件传输开始时它会读取“200”消息，然后是正在发送的文件的前几个Kb，它将被解析为字符数据。结果将是一堆错误。
我建议你现在摆脱BufferedReader并改用DataInputStream和DataOutputStream。您可以使用writeUTF和readUTF方法发送文本命令。要发送文件，我建议使用简单的块编码。
如果我给你代码，这可能是最简单的。
首先是您的客户类。
import java.io.*;
import java.net.InetAddress;
public class EchoClient2 {
public static void main(String[] args) {
InputStreamReader is = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(is);
File file = new File("C:\\MyFile.txt");
try {
System.out.println("Welcome to the Echo client.\n"
+ "What is the name of the server host?");
String hostName = br.readLine();
if( hostName.length() == 0 ) // if user did not enter a name
hostName = "localhost"; // use the default host name
System.out.println("What is the port number of the server host?");
String portNum = br.readLine();
if( portNum.length() == 0 ) portNum = "7"; // default port number
MyStreamSocket socket = new MyStreamSocket(
InetAddress.getByName(hostName), Integer.parseInt(portNum));
boolean done = false;
String echo;
while( !done ) {
System.out.println("Enter Code: 100 = Login, 200 = Upload, 400 = Logout: ");
String message = br.readLine();
boolean messageOK = false;
if( message.equals("100") ) {
messageOK = true;
System.out.println("Enter T-Number: (Use Uppercase 'T')");
String login = br.readLine();
if( login.charAt(0) == 'T' ) {
System.out.println("Login Worked fantastically");
} else {
System.out.println("Login Failed");
}
socket.sendMessage("100");
}
if( message.equals("200") ) {
messageOK = true;
socket.sendMessage("200");
socket.sendFile(file);
}
if( (message.trim()).equals("400") ) {
messageOK = true;
System.out.println("Logged Out");
done = true;
socket.sendMessage("400");
socket.close();
break;
}
if( ! messageOK ) {
System.out.println("Invalid input");
continue;
}
// get reply from server
echo = socket.receiveMessage();
System.out.println(echo);
} // end while
} // end try
catch (Exception ex) {
ex.printStackTrace();
} // end catch
} // end main
} // end class
然后你的服务器类：
import java.io.*;
import java.net.*;
public class EchoServer2 {
static final String loginMessage = "Logged In";
static final String logoutMessage = "Logged Out";
public static void main(String[] args) {
int serverPort = 7; // default port
String message;
if( args.length == 1 ) serverPort = Integer.parseInt(args[0]);
try {
// instantiates a stream socket for accepting
// connections
ServerSocket myConnectionSocket = new ServerSocket(serverPort);
/**/System.out.println("Daytime server ready.");
while( true ) { // forever loop
// wait to accept a connection
/**/System.out.println("Waiting for a connection.");
MyStreamSocket myDataSocket = new MyStreamSocket(
myConnectionSocket.accept());
/**/System.out.println("connection accepted");
boolean done = false;
while( !done ) {
message = myDataSocket.receiveMessage();
/**/System.out.println("message received: " + message);
if( (message.trim()).equals("400") ) {
// Session over; close the data socket.
myDataSocket.sendMessage(logoutMessage);
myDataSocket.close();
done = true;
} // end if
if( (message.trim()).equals("100") ) {
// Login
/**/myDataSocket.sendMessage(loginMessage);
} // end if
if( (message.trim()).equals("200") ) {
File outFile = new File("C:\\OutFileServer.txt");
myDataSocket.receiveFile(outFile);
myDataSocket.sendMessage("File received "+outFile.length()+" bytes");
}
} // end while !done
} // end while forever
} // end try
catch (Exception ex) {
ex.printStackTrace();
}
} // end main
} // end class
然后是StreamSocket类：
public class MyStreamSocket {
private Socket socket;
private DataInputStream input;
private DataOutputStream output;
MyStreamSocket(InetAddress acceptorHost, int acceptorPort)
throws SocketException, IOException {
socket = new Socket(acceptorHost, acceptorPort);
setStreams();
}
MyStreamSocket(Socket socket) throws IOException {
this.socket = socket;
setStreams();
}
private void setStreams() throws IOException {
// get an input stream for reading from the data socket
input = new DataInputStream(socket.getInputStream());
output = new DataOutputStream(socket.getOutputStream());
}
public void sendMessage(String message) throws IOException {
output.writeUTF(message);
output.flush();
} // end sendMessage
public String receiveMessage() throws IOException {
String message = input.readUTF();
return message;
} // end receiveMessage
public void close() throws IOException {
socket.close();
}
public void sendFile(File file) throws IOException {
FileInputStream fileIn = new FileInputStream(file);
byte[] buf = new byte[Short.MAX_VALUE];
int bytesRead;
while( (bytesRead = fileIn.read(buf)) != -1 ) {
output.writeShort(bytesRead);
output.write(buf,0,bytesRead);
}
output.writeShort(-1);
fileIn.close();
}
public void receiveFile(File file) throws IOException {
FileOutputStream fileOut = new FileOutputStream(file);
byte[] buf = new byte[Short.MAX_VALUE];
int bytesSent;
while( (bytesSent = input.readShort()) != -1 ) {
input.readFully(buf,0,bytesSent);
fileOut.write(buf,0,bytesSent);
}
fileOut.close();
}
} // end class
抛弃“助手”类。它没有帮助你。