我想写对象来存档并读取它们,但我收到了错误。 Main.java
中的第51行是while循环,它应该显示对象。
Exception in thread "main" java.io.EOFException
at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2626)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1321)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:373)
at com.sdajava.rwobj.Main.main(Main.java:51)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)
我的代码:先写对象并阅读它们。数据写入文件。
String fileName = "c://Users//lukas//obj.txt";
Person p1 = new Person("Jan", "Kowalski", 21);
Person p2 = new Person("Jan", "Kowalski", 21);
OutputStream fileOutputStream = null;
ObjectOutput objectOutputStream = null;
OutputStream bufferOut = null;
try {
fileOutputStream = new FileOutputStream(fileName);
bufferOut = new BufferedOutputStream(fileOutputStream);
objectOutputStream = new ObjectOutputStream(bufferOut);
objectOutputStream.writeObject(p1);
objectOutputStream.writeObject(p2);
objectOutputStream.close();
} finally {
if (objectOutputStream != null) {
objectOutputStream.close();
}
fileOutputStream.close();
bufferOut.close();
objectOutputStream.close();
}
try {
FileInputStream fileInputStream = new FileInputStream(fileName);
InputStream bufferIn = new BufferedInputStream(fileInputStream);
ObjectInputStream objectInputStream
= new ObjectInputStream(bufferIn);
Person readCase = null;
List<Person> recordList = new ArrayList<>();
do {
readCase = (Person) objectInputStream.readObject();
if (readCase != null) {
recordList.add(readCase);
}
} while (readCase != null);
fileOutputStream.close();
objectOutputStream.close();
} catch (FileNotFoundException err){
err.printStackTrace();
}
有什么问题?
答案 0 :(得分:2)
do {
readCase = (Person) objectInputStream.readObject();
if (readCase != null) {
recordList.add(readCase);
}
} while (readCase != null);
此循环不正确。 readObject()
在流结束时不返回null。只要你写了一个null就可以做到这一点。在流结束时抛出EOFException
。所以:
for (;;) {
try {
readCase = (Person) objectInputStream.readObject();
recordList.add(readCase);
}
catch (EOFException exc) {
break;
}
}
答案 1 :(得分:0)
正如评论中所指出的那样,你试图阅读更多的对象然后存储,如果你不知道存储的对象数量,你可以这样尝试:
try{
while(true)
recordList.add((Person) objectInputStream.readObject());
}
catch(EOFException ex){
//All objects are read when control is here
}