java中ObjectInputStream中的IOException [英] IOException in ObjectInputStream in java

问题描述

我的代码有问题。当我在代码中使用readObject时，我得到IOException。整个程序正常工作，但是当我想使用readObject时，我得到了这个异常，
这是我用来保存对象的代码：

I have problem with my code. I get IOException when I use readObject in my code. the whole program work correctly but when I want to use readObject I get this exception, this is the code I use for saving object:

        File f = new File("employees.obj");
    ObjectOutputStream objOut = null;

    try {

        objOut = new ObjectOutputStream(new BufferedOutputStream(
                new FileOutputStream(f)));
        objOut.writeObject(newEmployee);
        objOut.flush();

        System.out.println("Object is serialized.");

    } catch (FileNotFoundException e) {
        System.out.println("File not found!");

    } catch (IOException e) {
        System.out.println("Failed!");

    } finally {

        if (objOut != null) {
            try {

                objOut.close();
            } catch (IOException e) {
            }
        }
    }

这是我用来恢复对象的代码：

and it is the code I use for restoring object:

    File f = new File("employees.obj");
    ObjectInputStream objIn = null;
    ArrayList<Employee> c = new ArrayList<Employee>();
    try {
        objIn = new ObjectInputStream(new BufferedInputStream(
                new FileInputStream(f)));
        while (objIn.readObject() != null) {
            Person employee = (Person) objIn.readObject();
            System.out.println("hello");
            System.out.println(employee.toString());
        }
        System.out.println(c.toString());
        return c;

    } catch (FileNotFoundException e) {
        System.out.println("1");
    } catch (IOException e) {
        e.printStackTrace();
    } catch (ClassNotFoundException e) {
        System.out.println("3");
    } catch (ClassCastException e) {
        System.out.println("4");
    } finally {

        if (objIn != null) {
            try {
                objIn.close();
            } catch (IOException e) {
                System.out.println("4");
            }
        }
    }
    return c;

以及控制台中的结果：

at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2553)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1296)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
at org.bihe.DeSerializer.deSerializeEmployees(DeSerializer.java:20)
at org.bihe.Main.enterAsManager(Main.java:238)
at org.bihe.Main.menu(Main.java:92)
at org.bihe.Main.main(Main.java:50)

推荐答案

    while (objIn.readObject() != null) {

将解除一个对象（Person）的分解。然后是下一行：

will deseralize one object (Person). Then the next line:

        Person employee = (Person) objIn.readObject();

尝试解除下一个对象的deseralize。如果你在文件的末尾（EOF），那么它会抛出
IOException 。

attempts to deseralize the next object. If you're at the end of the file (EOF), then it throws IOException.

要解决此问题，请执行以下操作：

To fix this do something like this:

    Person employee;
    while ((employee = (Person)objIn.readObject()) != null) {
        System.out.println("hello");
        System.out.println(employee.toString());
    }

while比较 readObject（） with null并将其分配给 employee 。

The while compares readObject() with null and assigns it to employee.

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