“java.io.StreamCorruptedException：无效类型代码：AC”- 从服务器-客户端 java 程序运行客户端代码时发现错误
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"java.io.StreamCorruptedException: invalid type code: AC"- Error found while running the client code from the server-client java program
提问by Atif S.
Well, I am trying to read a .xml file from the XMLParser so basically I want to read the XML files and print it out from the server to the client, but while running the client code i am getting:
好吧，我正在尝试从 XMLParser 读取 .xml 文件，所以基本上我想读取 XML 文件并将其从服务器打印到客户端，但是在运行客户端代码时我得到：
java.io.StreamCorruptedException: invalid type code: AC
The Client code is:
客户端代码是：
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.List;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import server.Video;
import server.VideoFile;
@SuppressWarnings("serial")
public class Client extends JFrame{
Container contentPane;
@SuppressWarnings("rawtypes")
JComboBox selectionBox;
List<Video> video;
List<VideoFile> videoFile;
Socket serverSocket;
String host = "127.0.0.1";
int port = 1176;
ObjectInputStream inputFromServer;
ObjectOutputStream out;
public Client() throws Exception {
// line 41 below
setupGUI();
System.out.println("Reading the XML File");
MyXMLReader reader = new MyXMLReader();
//video = reader.getList("videoList.xml");
System.out.println("Finished reading");
}
public void openSocket() throws UnknownHostException, IOException {
/** Obtain an address object of the server */
serverSocket = new Socket("localhost", port);
System.out.println("Connected to localhost in port: " + port);
out = new ObjectOutputStream(serverSocket.getOutputStream());
//out.flush();
inputFromServer = new ObjectInputStream(serverSocket.getInputStream());
}
@SuppressWarnings("unchecked")
public void getListFromSocket() throws IOException, ClassNotFoundException {
try{
video = (List<Video>)inputFromServer.readObject();
} catch (IOException e) {
e.printStackTrace();
System.exit(-1);
}
//serverSocket.close();
}
public void runClient() throws Exception {
try {
openSocket();
getListFromSocket();
serverSocket.close();
setupGUI();
} catch (UnknownHostException e) {
System.out.println("Don't know about host : " + host);
System.exit(-1);
} catch (IOException e) {
e.printStackTrace();
System.out.println("Couldn't open I/O connection : " + host + ":" + port);
System.exit(-1);
} catch (ClassNotFoundException e) {
System.out.println("Class definition not found for incoming object.");
e.printStackTrace();
System.exit(-1);
}
}
@SuppressWarnings({ "unchecked", "rawtypes" })
private void setupGUI() throws Exception{
setTitle("A Client");
setSize(600, 400);
setVisible(true);
contentPane = getContentPane();
contentPane.setLayout(new BorderLayout());
runClient();
// line 105 below
String [] selectionListData = new String[video.size()];
for (int i = 0; i < video.size(); i++) {
selectionListData[i] = video.get(i).getFilename();
selectionListData[i] = video.get(i).getID();
selectionListData[i] = video.get(i).getTitle();
System.out.println(selectionListData);
}
selectionBox = new JComboBox(selectionListData);
selectionBox.setSelectedIndex(0);
add(selectionBox, BorderLayout.NORTH);
selectionBox.addActionListener((ActionListener) this);
validate();
}
public void actionPerformed(ActionEvent e) {
@SuppressWarnings("rawtypes")
JComboBox comboBox = (JComboBox)e.getSource();
String selectedTitle = (String)comboBox.getSelectedItem();
System.out.println("Selected title : " + selectedTitle);
}
public static void main(String[] args) throws IOException, Exception {
// line 127 below
new Client();
}
}
The full error is:
完整的错误是：
Connected to localhost in port: 1176
java.io.StreamCorruptedException: invalid type code: AC
at java.io.ObjectInputStream.readObject0(Unknown Source)
at java.io.ObjectInputStream.readObject(Unknown Source)
at client.Client.getListFromSocket(Client.java:61)
at client.Client.runClient(Client.java:72)
at client.Client.<init>(Client.java:40)
at client.Client.main(Client.java:124)
Can anyone give a fix to this, I am sure its something small but I can't figure it out though.
任何人都可以解决这个问题，我确定它很小，但我无法弄清楚。
Thanks
谢谢
EDIT: The server code is:
编辑：服务器代码是：
package server;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.List;
import java.lang.*;
@SuppressWarnings("unused")
public class Server extends Thread implements Runnable{
List<Video> video;
static String TimeStamp;
//Socket Declerations
ServerSocket serverSocket;
int port = 1176;
//String host = "localhost";
Socket clientSocket;
ObjectOutputStream outputToClient;
public Server() {
Thread();
System.out.println("Reading the XML File");
MyXMLReader reader = new MyXMLReader();
//video = reader.getList("videoList.xml");
System.out.println("Finished reading");
}
public void openSockets() throws IOException {
try {
serverSocket = new ServerSocket(port);
System.out.println("Socket Connection Established....");
} catch (IOException e) {
System.out.println("Could not listen on port : " + port);
System.exit(-1);
}
TimeStamp = new java.util.Date().toString();
System.out.println("Opened socket on : " + port + ", waiting for client. " + TimeStamp);
try {
clientSocket = serverSocket.accept();
//System.out.println("Sending to Client.....");
} catch (IOException e) {
System.out.println("Could not accept client.");
System.exit(-1);
}
outputToClient = new ObjectOutputStream(clientSocket.getOutputStream());
}
public void writeToSocket() throws IOException {
outputToClient = new ObjectOutputStream(clientSocket.getOutputStream());
outputToClient.writeObject(video);
System.out.println(outputToClient);
}
public void Thread() {
Thread socketThread;
socketThread = new Thread("Socket") {
public void run() {
try {
openSockets();
writeToSocket();
clientSocket.close();
serverSocket.close();
} catch (IOException e) {
System.out.println("Error on sockets connection.");
e.printStackTrace();
}
}
};
socketThread.start();
}
public static void main(String[] args) throws IOException {
new Server();
//new Thread();
}
}
EDIT: New error after deleting the duplicate entry:
编辑：删除重复条目后出现新错误：
Exception in thread "main" java.lang.NullPointerException
at client.Client.setupGUI(Client.java:105)
at client.Client.<init>(Client.java:41)
at client.Client.main(Client.java:127)
回答by Krrose27
You are double opening an ObjectOutputStream on the same socket in the Server class which is causing special headers to be sent twice.
您在 Server 类中的同一个套接字上打开了一个 ObjectOutputStream，这导致特殊标头被发送两次。
1: openSocketslast line outputToClient = new ObjectOutputStream(clientSocket.getOutputStream());
1：openSockets最后一行outputToClient = new ObjectOutputStream(clientSocket.getOutputStream());
2: writeToSocketfirst line outputToClient = new ObjectOutputStream(clientSocket.getOutputStream());
2：writeToSocket第一行outputToClient = new ObjectOutputStream(clientSocket.getOutputStream());
Remove whichever one you want and it should work just fine.
删除您想要的任何一个，它应该可以正常工作。
As for the nullpointer you are now receiving I have a feeling that video is null in the client. In the code you have posted that would make sense because in the server you never create a video array and as such the client is just receiving null.
至于您现在收到的空指针，我感觉客户端中的视频为空。在您发布的代码中，这是有道理的，因为在服务器中您从不创建视频数组，因此客户端只是接收空值。
回答by user207421
This error is caused by using more than one ObjectOutputStreamon the same socket. Use the same ObjectOutputstreamand ObjectInputStreamfor the life of the socket, at both ends. Same goes for most other stream and reader/writer types, except that the consequences of not doing so are usually even more mysterious.
此错误是由ObjectOutputStream在同一个套接字上使用多个引起的。在插座的两端使用相同的ObjectOutputstream和ObjectInputStream终生的。大多数其他流和读取器/写入器类型也是如此，只是不这样做的后果通常更加神秘。
