ObjectInputStream registerValidation()方法

java.io.ObjectInputStream.registerValidation(ObjectInputValidation obj, int prio) 方法用于注册对象的图形被返回之前进行验证。虽然类似resolveObject这些验证被称为整个图形被改组之后。通常情况下，一个readObject方法将注册对象，这样，当所有的对象都恢复了最后一组的验证可以进行数据流。

1 语法

public void registerValidation(ObjectInputValidation obj, int prio)

2 参数

obj：接收验证回调的对象。

prio：控制回调的顺序，0是一个很好的默认值。使用更高的数字被称为背前面，较小的数字后回调。在一个优先级，回调在没有特定的顺序进行处理。

3 返回值

无

4 示例 

package com.yiidian;

/**
 * 一点教程网： http://www.yiidian.com
 */
/**
 * java.io.ObjectInputStream.registerValidation(ObjectInputValidation obj, int prio)方法的例子
 */
import java.io.*;

public class Demo {

    public static void main(String[] args) {

        try {

            // create a new file with an ObjectOutputStream
            FileOutputStream out = new FileOutputStream("test.txt");
            ObjectOutputStream oout = new ObjectOutputStream(out);

            // write something in the file
            oout.writeObject(new Example());
            oout.flush();

            // create an ObjectInputStream for the file we created before
            ObjectInputStream ois =
                    new ObjectInputStream(new FileInputStream("test.txt"));

            // read the object and print the string
            Example a = (Example) ois.readObject();

            // print the string that is in Example class
            System.out.println("" + a.s);

            // validate the object
            a.validateObject();


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


    }

    static class Example implements Serializable, ObjectInputValidation {

        String s = "Hello World!";

        private String readObject(ObjectInputStream in)
                throws IOException, ClassNotFoundException {

            // call readFields in readObject
            ObjectInputStream.GetField gf = in.readFields();

            // register validation for the object
            in.registerValidation(this, 0);

            // save the string and return it
            return (String) gf.get("s", null);

        }

        public void validateObject() throws InvalidObjectException {
            System.out.println("Validating object...");
            if (this.s.equals("Hello World!")) {
                System.out.println("Validated.");
            } else {
                System.out.println("Not validated.");
            }
        }
    }
}

输出结果为：

Hello World!
Validating object...
Validated.