Java操作IO对象流进行数据的读写

对象的读写
使用ObjectInputStream和ObjectOutputStream读写对象(序列化与反序列化)。

只有字节流没有字符流

1. .类必须实现Serializable接口
2. 给类加个序列化编号，给类定义一个标记，新的修改后的类还可以操作曾经序列化的对象
3. 静态是不能被序列化的，序列化只能对堆中的进行序列化 ，不能对“方法区”中的进行序列化
4. 不需要序列化的字段前加 transient

小例子：

先创建一个Dog对象并序列化:

package com.uwo9.test03;

import java.io.Serializable;

public class Dog implements Serializable {
    private static final long serialVersionUID = 2809685095868158625L;
    String name;
    String color;
}

再创建一个Student对象并序列化：

package com.uwo9.test03;

import java.io.Serializable;

public class Student implements Serializable {
    private static final long serialVersionUID = 9078616504949971001L;
    static public  String schoolName;
    private transient String name;
    private transient int age;
    private double score;
    private Dog dog;
    public Student() {
        super();
    }
    public Student(String name, int age, double score, Dog dog) {
        super();
        this.name = name;
        this.age = age;
        this.score = score;
        this.dog = dog;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public double getScore() {
        return score;
    }
    public void setScore(double score) {
        this.score = score;
    }
    @Override
    public String toString() {
        return "Student [name=" + name + ", age=" + age + ", score=" + score + "]";
    }

}

将数据写入对象流并存入文件

package com.uwo9.test03;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
import java.util.Collections;

public class Test01 {

    public static void main(String[] args) {
        Dog dog = new Dog();
        dog.name = "大黄";
        dog.color = "Yellow";
        Student student1 = new Student("学生1", 18, 99,dog);
        Student student2 = new Student("学生2", 19, 99,dog);
        Student student3 = new Student("学生3", 20, 99,dog);
        Student.schoolName = "某某大学";
        File file = new File("E:/Temp/Test1.txt");
        ObjectOutputStream oos = null;
        try {
            oos = new ObjectOutputStream(new FileOutputStream(file));
            //oos.writeObject(student);
            ArrayList<Student> arrayList = new ArrayList<>();
            Collections.addAll(arrayList, student1,student2,student3);
            oos.writeObject(arrayList);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            try {
                oos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }

}

从指定文件中读取对象

package com.uwo9.test03;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.util.ArrayList;

public class Test02 {

    public static void main(String[] args) {
        // 从指定的文件中读取对象
        File file = new File("E:/Temp/Test1.txt");
        ObjectInputStream ois=null;
        try {
            ois = new ObjectInputStream(new FileInputStream(file));
            // 读取对象
            // Student stu = (Student)ois.readObject();
            // System.out.println("读取到的数据为:"+stu);
            @SuppressWarnings("unchecked")
            ArrayList<Student> arrayList = (ArrayList<Student>) ois.readObject();
            for (Student student : arrayList) {
                System.out.println(student);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }finally {
            try {
                ois.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }

}

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原文链接：https://blog.csdn.net/huanyinghanlang/article/details/78828347