问题
I am trying to add an object( of OneChatMessage class) into a file on every button click. And then i try to read all the objects from the file and load it into a ArrayList. But i get a StreamCorruptedException at the second iteration of ObjectInputStream.readObject() in the deserialization function. I have verified that the first iteration works fine.
I have read many other posts on the same issue :
- One suggestion(Deserialize multiple Java Objects) is to write the entire array list to the file instead of individual objects. But that seems wasteful, as i need to write to file on every button click and there would be hundreds of objects over time.
- Another suggestion(StreamCorruptedException: invalid type code: AC) is to do with different headers created by ObjectOutputStream. I have no idea who to use this knowledge to resolve the issue.
Any idea on how i can resolve this?
OneChatMessage.java :
package com.slapp.chat;
import java.io.Serializable;
import java.util.Date;
import com.slapp.localDB.Contact;
//This class defines the class for a chat message
public class OneChatMessage implements Serializable{
private String text;
private Date timeSent;
private Boolean sentByMe;
public OneChatMessage(String text, Date timeSent, Boolean sentByMe){
this.text = text;
this.timeSent = timeSent;
this.sentByMe = sentByMe;
}
public String getText(){
return this.text;
}
public Date getTimeSent(){
return this.timeSent;
}
@Override
public String toString(){
return new StringBuffer(" Text : ")
.append(this.text)
.append(" TimeSent : ")
.append(this.timeSent.toString()) // Need to use SimpleDatFormat to get the correct time zone and formatting. Leaving it for now.
.append(" SentByMe : ")
.append(this.sentByMe.toString()).toString();
}
}
Serializing function :
public void addMessage(OneChatMessage msg) {
FileOutputStream fos;
ObjectOutputStream oos;
File file = new File(context.getFilesDir(), "abc");
if (!file.exists()) {
Log.d("faizal",
"The file does not exist : ");
} else {
Log.d("faizal",
"The file already exists : ");
}
try {
fos = context.openFileOutput("abc",
Context.MODE_APPEND);
oos = new ObjectOutputStream(fos);
oos.writeObject(msg);
oos.close();
fos.close();
} catch (FileNotFoundException e) {
Log.d("faizal", "file not found : ");
e.printStackTrace();
} catch (IOException e) {
Log.d("faizal", "Error closing file : ");
e.printStackTrace();
}
}
Deserializing function :
public ArrayList<OneChatMessage> getAllChatMessagesArrayList() {
ArrayList<OneChatMessage> chatMessages = new ArrayList<OneChatMessage>();
OneChatMessage oneChatMsg;
FileInputStream fis;
ObjectInputStream ois;
try {
fis = context.openFileInput("abc");
ois = new ObjectInputStream(fis);
//Setting an arbitrarily large number as the limit of the loop iterations
//so that chat message are read from the file till EOF
for (int i = 1; i < 999999999; i++) {
try {
oneChatMsg = (OneChatMessage) ois.readObject();
} catch (EOFException e) {
//When EOFException occurs, quit the loop
break;
}
try{
chatMessages.add(oneChatMsg);
} catch(Exception e){
Log.d("faizal","Error adding message to Array List:" + oneChatMsg.getText());
e.printStackTrace();
}
}
ois.close();
fis.close();
return chatMessages;
} catch (FileNotFoundException e) {
Log.d("faizal", "The file not found : ");
e.printStackTrace();
} catch (IOException e) {
Log.d("faizal", "Error closing file : ");
e.printStackTrace();
} catch (ClassNotFoundException e) {
Log.d("faizal","Error reading object from file : ");
e.printStackTrace();
} catch (UnsupportedOperationException e) {
Log.d("faizal", "Error adding object to array list from file : ");
e.printStackTrace();
}
return null; // in case there was a caught exception
}
Logcat :
05-27 16:56:17.576: W/System.err(25028): java.io.StreamCorruptedException: Wrong format: ac
05-27 16:56:17.576: W/System.err(25028): at java.io.ObjectInputStream.corruptStream(ObjectInputStream.java:701)
05-27 16:56:17.576: W/System.err(25028): at java.io.ObjectInputStream.readNonPrimitiveContent(ObjectInputStream.java:814)
05-27 16:56:17.576: W/System.err(25028): at java.io.ObjectInputStream.readObject(ObjectInputStream.java:2006)
05-27 16:56:17.576: W/System.err(25028): at java.io.ObjectInputStream.readObject(ObjectInputStream.java:1963)
05-27 16:56:17.576: W/System.err(25028): at com.slapp.chat.ChatPersistenceHandler.getAllChatMessagesArrayList(ChatPersistenceHandler.java:62)
05-27 16:56:17.576: W/System.err(25028): at com.example.slapp.ChatSessionActivity$ChatArrayAdapter.<init>(ChatSessionActivity.java:178)
05-27 16:56:17.576: W/System.err(25028): at com.example.slapp.ChatSessionActivity.onCreate(ChatSessionActivity.java:86)
05-27 16:56:17.576: W/System.err(25028): at android.app.Activity.performCreate(Activity.java:5372)
05-27 16:56:17.576: W/System.err(25028): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1104)
05-27 16:56:17.576: W/System.err(25028): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2270)
05-27 16:56:17.576: W/System.err(25028): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2362)
05-27 16:56:17.576: W/System.err(25028): at android.app.ActivityThread.access$700(ActivityThread.java:168)
05-27 16:56:17.576: W/System.err(25028): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1329)
05-27 16:56:17.576: W/System.err(25028): at android.os.Handler.dispatchMessage(Handler.java:99)
05-27 16:56:17.576: W/System.err(25028): at android.os.Looper.loop(Looper.java:137)
05-27 16:56:17.576: W/System.err(25028): at android.app.ActivityThread.main(ActivityThread.java:5493)
05-27 16:56:17.576: W/System.err(25028): at java.lang.reflect.Method.invokeNative(Native Method)
05-27 16:56:17.576: W/System.err(25028): at java.lang.reflect.Method.invoke(Method.java:525)
05-27 16:56:17.576: W/System.err(25028): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1209)
05-27 16:56:17.576: W/System.err(25028): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1025)
05-27 16:56:17.576: W/System.err(25028): at dalvik.system.NativeStart.main(Native Method)
回答1:
Appending to an ObjectOutputStream doesn't work out of the box as it creates multiple headers as described in StreamCorruptedException: invalid type code: AC.
See Appending to an ObjectOutputStream for a solution.
来源：https://stackoverflow.com/questions/23889486/java-io-streamcorruptedexception-wrong-format-when-reading-more-than-1-object