我正在制作一个使用客户端套接字和服务器套接字的Messenger程序，但是当运行DataInputStream.readUTF（）方法时，我一直遇到问题。我得到一个java.io.EOFException。 对我糟糕的编程和非常命名的变量感到抱歉。 我的客户的代码大多就在这里。
import java.awt.CardLayout;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.ScrollPane;
import java.awt.Scrollbar;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
public class GUI extends JFrame implements ActionListener{
private InetAddress inet;
private Socket s = new Socket();enter code here
private DataOutputStream output;
private DataInputStream input;
private JButton send;
private JTextArea tarea;
private BufferedReader br;
private JTextField tf;
private JTextField ip;
private JTextField port;
private JButton connect;
private JPanel one;
private JPanel two;
private CardLayout cardlayout;
private JPanel cards;
private JTextField uname;
private JScrollPane scroll;
private Thread listen;
String a;
//contructor
public GUI() {
super("Messenger v2.0");
cards = new JPanel(new CardLayout());
tarea = new JTextArea(10,30);
scroll = new JScrollPane(tarea);
tf = new JTextField("type your message here", 20);
send = new JButton("Send");
ip = new JTextField("ip", 5);
port = new JTextField("port", 5);
connect = new JButton("Connect");
uname = new JTextField("Type your username", 13);
one = new JPanel();
one();
two = new JPanel();
two();
cards.add(one, "1");
cards.add(two, "2");
first();
}//end constructor
//one method
public void one(){
one.add(ip);
one.add(port);
one.add(uname);
one.add(connect);
}//end one method
//two method
public void two(){
two.add(scroll);
two.add(tf);
two.add(send);
}//end two method
//first method
public void first(){
add(cards);
cardlayout = (CardLayout) cards.getLayout();
cardlayout.show(cards, "1");
connect.addActionListener(this);
}//end first method
//second method
public void second(){
cardlayout.show(cards, "2");
setSize(400, 300);
}//end second method
//action performed
@Override
public void actionPerformed(ActionEvent e) {
if(e.getSource() == connect){
second();
String ip = this.ip.getText();
String port = this.port.getText();
try {
connect();
} catch (NumberFormatException | IOException e1) {
e1.printStackTrace();
}
second();
}
else if(e.getSource() == send){
try {
send(tf.getText());
} catch (Exception e1) {
}
}
}//end actionperformed
//connect method
public void connect() throws NumberFormatException, IOException{
String z = ip.getText();
inet = InetAddress.getByName(z);;
s = new Socket(inet, Integer.parseInt(port.getText()));
input = new DataInputStream(s.getInputStream());
this.output = new DataOutputStream(this.s.getOutputStream());
String g;
g = uname.getText() + " has joined the chat";
send(g);
//thread to listen
listen = new Thread(){
public void run(){
while(true){
if(s.isInputShutdown() == false){
try {
a = input.readUTF();
if(a.equals("DISSCONNECT_SESSION") || a.equals("-1") || a.equals(-1) || a.equals(null)){
input.close();
break;
}
write(a);
a = null;
}
catch (IOException e) {
e.printStackTrace();
}
}else{
break;
}
}
}
};
listen.start();
}//end connect() method
//send(String) method
private void send(String text) throws IOException {
output.writeUTF(text);
write(text);
}//end send(String) method
//write method
public void write(String message){
tarea.setText(tarea.getText() + "\n" + message );
}//end write(String message) method
}//end class
我的大多数服务器代码都是。
import java.io.BufferedWriter;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
public class The_Server {
DataInputStream input;
DataOutputStream output;
Seconday_Thread st;
String help2;
The_Main tm;
private ServerSocket ss;
private Socket s;
private ArrayList<Socket> cs = new ArrayList<Socket>();
private ArrayList<DataOutputStream> outputs = new ArrayList<DataOutputStream>();
String name;
int counter;
public void createServer(String a) throws IOException{
int b = Integer.parseInt(a);
ss = new ServerSocket(b);
counter = 0;
while (true){
s = ss.accept();
cs.add(counter, s);
output = new DataOutputStream(cs.get(counter).getOutputStream());
outputs.add(counter, output);
input = new DataInputStream(cs.get(counter).getInputStream());
name = input.readUTF();
send("has joined", name);
counter++;
st = new Seconday_Thread(input, name); // this thread is DataInputStream.readUTF() in a while loop
st.start();
}
}
public void send(String text, String name) {
int counter_num_2 = 0;
while(true){
if(outputs.get(counter_num_2).equals(null)){
break;
}
else{
if(counter_num_2 == 40){
break;
}
else if(cs.get(counter_num_2).isClosed()){
}
else if(cs.get(counter_num_2).isClosed() && counter_num_2 == 39){
counter = 0;
break;
}
else{
try {
help2 = name + " " + text;
tm = new The_Main();
tm.sendToServer(name, text);
outputs.get(counter_num_2).writeUTF(help2);
outputs.get(counter_num_2).flush();
} catch (Exception e) {
try {
cs.get(counter_num_2).close();
} catch (IOException e1) {
}
}
counter_num_2++;
}
}
}
}
}
有人可以看看代码并发现错误，我花了很多时间并且无法弄明白。
答案 0 :(得分：0)
DataStreams使用EOFException来检测文件结束条件。您应该使用异常，而不是检查流中的特定字符串以关闭连接。