package com.sxd.swapping.objoutputstream;

import org.junit.Test;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import java.time.LocalDate;

import java.util.ArrayList;

import java.util.List;

/**

 *  ObjectOutputStream 写对象到序列化文件中

 *  ObjectInputStream  读对象到反序列化文件中

 */

public class SerializeTest {

    /**

     * 写生成序列化文件

     *

     * 对同一个 共享对象 做重复性的多次写入 建议使用writeObject + reset方法 组合使用 做重置动作 （即深克隆效果）下面这个 方法写入的 是 test1 test2  test3 三条。

     * 对于 非共享对象， 做多次重复性的写入  可以使用 writeUnshared 方法（即浅克隆效果）

     *

     *

     *

     * 而 单独使用 writeObject方法，会导致 第二次写入的对象 依旧是 第一次写对的对象。即 流不对被重置，导致下面这个 方法写入的 是错误的 test1 test2  test1  test2 四条。

     *

     * @throws Exception

     */

    @Test

    public void test3() throws Exception {

        List<Student> students = new ArrayList<>();

        ObjectOutputStream objectOutputStream = new ObjectOutputStream(new FileOutputStream(new File("C:/Users/ouiyuio/Desktop/students.ser")));

        for (int i = 1; i <= 3; i++) {

            Student student = new Student(i, "test" + i);

            students.add(student);

            if (students.size() >= 2) {

                // objectOutputStream.writeUnshared(students);

                objectOutputStream.writeObject(students);

                objectOutputStream.reset();  //使用 reset保证写入重复对象时进行了重置操作

                students.clear();

            }

        }

        if (students.size() > 0) {

            objectOutputStream.writeObject(students);

            objectOutputStream.flush();

        }

        objectOutputStream.writeObject(null);

        objectOutputStream.close();

    }

    /**

     * 反序列化读取文件内容

     * @throws Exception

     */

    @Test

    public void test4() throws Exception {

        ObjectInputStream objectInputStream = new ObjectInputStream(new FileInputStream(new File("C:/Users/ouiyuio/Desktop/students.ser")));

        List<Student> students = (List<Student>) objectInputStream.readObject();

        int count = 0;

        while (students != null) {

            count += students.size();

            for (Student student : students) {

                System.out.println(student);

            }

            students = (List<Student>) objectInputStream.readObject();

        }

        objectInputStream.close();

        System.out.println(count);

    }

    @Test

    public void test5() throws Exception {

        int count = 0;

        ObjectInputStream objectInputStream = new ObjectInputStream(new FileInputStream(new File("C:/Users/ouiyuio/Desktop/students.ser")));

        List<Student> students1 = (List<Student>) objectInputStream.readObject();

        count += students1.size();

        for (Student student : students1) {

            System.out.println(student);

        }

        List<Student> students2 = (List<Student>) objectInputStream.readObject();

        count += students2.size();

        for (Student student : students2) {

            System.out.println(student);

        }

        objectInputStream.close();

        System.out.println(count);

    }

}