java Java 中 ObjectInputStream defaultReadObject()方法，带示例

Java 中 ObjectInputStream defaultReadObject()方法，带示例

原文:https://www . geesforgeks . org/objectinputstream-defaultreadobject-method-in-Java-with-examples/

Java 中 ObjectInputStream 类的 defaultReadObject() 方法用于从该流中读取当前类的非静态和非瞬态字段。

语法:

public void defaultReadObject()

参数:此方法不接受任何参数。

返回值:该方法返回已读取的值。

错误和异常:函数抛出三个异常，如下所述:

ClassNotFoundException: 如果找不到序列化对象的类，将引发异常。
IOException: 如果出现输入/输出错误，将引发异常。
NotActiveException: 如果流当前没有读取对象，则会引发异常。

下面的程序说明了上面的方法:

程序 1:

Java 语言(一种计算机语言，尤用于创建网站)

// Java program to illustrate
// the above method

import java.io.*;

public class GFG {
    public static void main(String[] args)
    {
        try {
            // create a new file
            // with an ObjectOutputStream
            FileOutputStream out
                = new FileOutputStream("Shubham.txt");
            ObjectOutputStream out1
                = new ObjectOutputStream(out);

            // write
            out1.writeObject(new solve());

            // Flushes the stream
            out1.flush();

            // create an ObjectInputStream
            // for the file
            ObjectInputStream example
                = new ObjectInputStream(
                    new FileInputStream("Shubham.txt"));

            // Read from the stream
            solve ans = (solve)example.readObject();
            System.out.println(ans.str);
        }

        catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    static class solve implements Serializable {
        String str = "Geeksforgeeks";

        private void readObject(ObjectInputStream res)
            throws IOException,
                   ClassNotFoundException
        {

            // By using defaultReadObject() method is
            // to read non-static fields of the present
            // class from the ObjectInputStream
            res.defaultReadObject();
        }
    }
}

输出:

程序 2:

Java 语言(一种计算机语言，尤用于创建网站)

// Java program to illustrate
// the above method

import java.io.*;

public class GFG {
    public static void main(String[] args)
    {
        try {
            // create a new file
            // with an ObjectOutputStream
            FileOutputStream out
                = new FileOutputStream("Shubham.txt");
            ObjectOutputStream out1
                = new ObjectOutputStream(out);

            // write
            out1.writeObject(new solve());

            // Flushes the stream
            out1.flush();

            // create an ObjectInputStream
            // for the file
            ObjectInputStream example
                = new ObjectInputStream(
                    new FileInputStream("Shubham.txt"));

            // Read from the stream
            solve ans = (solve)example.readObject();
            // System.out.println(ans.str);
            System.out.println(ans.in);
        }

        catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    static class solve implements Serializable {

        // String str = "Geeksforgeeks";
        Integer in = new Integer(112414);

        private void readObject(ObjectInputStream res)
            throws IOException,
                   ClassNotFoundException
        {
            // By using defaultReadObject() method is
            // to read non-static fields of the present
            // class from the ObjectInputStream
            res.defaultReadObject();
        }
    }
}