I/O流07：序列化与反序列化

一、序列化

1、什么是序列化

• 把Java对象转换为字节序列存储到计算机文件中的过程
• 在传递和保存对象时.保证对象的完整性和可传递性。对象转换为有序字节流,以便在网络上传输或者保存在本地文件中

2、序列化代码演示

• 创建一个Teacher类

在这里插入代码片public class Teacher implements Serializable {
    private String name;

    public Teacher(String name) {
        this.name = name;
    }

    public Teacher() {
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "Teacher{" +
                "name='" + name + '\'' +
                '}';
    }
}

• 创建一个Student类

public class Student implements Serializable {
    private String name;
    private String sex;
    //瞬事状态，不写入文件
    private transient int age;
    private Teacher teacher;

    public Student() {
    }

    public Student(String name, String sex, int age, Teacher teacher) {
        this.name = name;
        this.sex = sex;
        this.age = age;
        this.teacher = teacher;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public Teacher getTeacher() {
        return teacher;
    }

    public void setTeacher(Teacher teacher) {
        this.teacher = teacher;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                ", age=" + age +
                ", teacher=" + teacher +
                '}';
    }
}

• 将Student类的实例序列化到student.data文件中去

public class 序列化流 {
    public static void main(String[] args) throws Exception {
        //创建对象序列化输出流
        ObjectOutputStream objectOutputStream = new ObjectOutputStream(new FileOutputStream("student.data"));
        //创建一个Teacher对象
        Teacher teacher = new Teacher("廖常");
        Student student = new Student("廖常","男",24,teacher);

        objectOutputStream.writeObject(student);

//        objectOutputStream.writeObject(teacher);
        objectOutputStream.close();
    }
}

• 运行结果
  

二、反序列化

1、什么是反序列化

• 指把存储在计算机文件中的字节序列恢复为Java对象的过程
• 根据字节流中保存的对象状态及描述信息，通过反序列化重建对象

2、反序列化代码演示

• 将student.data文件中存储的对象反序列化到内存中显示

public class 反序列化流 {
    public static void main(String[] args) throws Exception {
        ObjectInputStream objectInputStream = new ObjectInputStream(new FileInputStream("student.data"));
        //反序列化
        Student student = (Student)objectInputStream.readObject();
        objectInputStream.close();
        System.out.println(student.toString());

    }
}

• 运行结果