1.用对象序列化流序列化了一个对象后，假如我们修改了对象所属的类文件，读取数据会不会出问题？如果出问题了，如何解决？
2.如果一个对象中的某个成员变量的值不想被序列化，又该如何实现呢？

首先定义一个Student类，并进行序列化操作

package demo17;

import java.io.Serializable;

public class Student implements Serializable {private String name;
    private int chinese;
    private int math;

    public Student() {
    }

    public Student(String name, int chinese, int math) {
        this.name = name;
        this.chinese = chinese;
        this.math = math;
    }

    public String getName() {
        return name;
    }

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

    public int getChinese() {
        return chinese;
    }

    public void setChinese(int chinese) {
        this.chinese = chinese;
    }

    public int getMath() {
        return math;
    }

    public void setMath(int math) {
        this.math = math;
    }

    public int getSum() {
        return this.getChinese() + this.getMath();
    }
}

package demo17;

import java.io.*;

public class Demo01ObjectStream {
    public static void main(String[] args) throws IOException, ClassNotFoundException {
        write();
        read();
    }
//序列化
    private static void write() throws IOException {
        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("src\\oos.txt"));
        Student s1 = new Student("张三", 98, 50);
        oos.writeObject(s1);
        oos.close();

    }
//反序列化
    private static void read() throws IOException, ClassNotFoundException {
        ObjectInputStream ois = new ObjectInputStream(new FileInputStream("src\\oos.txt"));
        Object obj = ois.readObject();
        Student s=(Student) obj;
        System.out.println(s.getName() + "," + s.getChinese() + "," + s.getMath());
        ois.close();
    }
}

当然可以正常执行！

1.用对象序列化流序列化了一个对象后，假如我们修改了对象所属的类文件，读取数据会不会出问题？如果出问题了，如何解决？

接下来如果在Student类生成toString();方法

重新运行发现报错

java.io.InvalidClassException:
        demo17.Student; local class incompatible:
        stream classdesc serialVersionUID = 7074576674008727580,
        local class serialVersionUID = 7515218800045627898

解决方法就是给对象所属的类加一个值，private static final long serialVersionUID = 42L;

2.如果一个对象中的某个成员变量的值不想被序列化，又该如何实现呢？

给成员变量加transient关键字修饰，该关键字标记的成员变量不参与序列化过程
修改过后的Student类为

package demo17;

import java.io.Serializable;

public class Student implements Serializable {
    private static final long serialVersionUID = 42L;
    private String name;
    private int chinese;
    private transient int math;

    public Student() {
    }

    public Student(String name, int chinese, int math) {
        this.name = name;
        this.chinese = chinese;
        this.math = math;
    }

    public String getName() {
        return name;
    }

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

    public int getChinese() {
        return chinese;
    }

    public void setChinese(int chinese) {
        this.chinese = chinese;
    }

    public int getMath() {
        return math;
    }

    public void setMath(int math) {
        this.math = math;
    }

    public int getSum() {
        return this.getChinese() + this.getMath();
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", chinese=" + chinese +
                ", math=" + math +
                '}';
    }
}

重新运行，发现并不会报错，并且math属性也没有显示。