java.io.Serializable 序列化问题

Posted 2020-07-09 万物生长

java.io.Serializable 序列化问题

Person.java

package a.b.c;

public class Person implements java.io.Serializable{
    
//    private static final long serialVersionUID = 2481632967198330813L;
    
    String field1;
    String field2;
    String field3;
    public String getField1() {
        return field1;
    }
    public void setField1(String field1) {
        this.field1 = field1;
    }
    public String getField2() {
        return field2;
    }
    public void setField2(String field2) {
        this.field2 = field2;
    }
    public String getField3() {
        return field3;
    }
    public void setField3(String field3) {
        this.field3 = field3;
    }
    
}

View Code

 

Student.java   Student继承自Person,但为了清晰表示,按Person一模一样又覆盖了一遍

package a.b.c;

public class Student  extends Person implements java.io.Serializable {
    
//    private static final long serialVersionUID = 2481632967198330813L;
    
    String field1;
    String field2;
    String field3;
    public String getField1() {
        return field1;
    }
    public void setField1(String field1) {
        this.field1 = field1;
    }
    public String getField2() {
        return field2;
    }
    public void setField2(String field2) {
        this.field2 = field2;
    }
    public String getField3() {
        return field3;
    }
    public void setField3(String field3) {
        this.field3 = field3;
    }

}

View Code

 

SerializableWriter.java

package a.b.c;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

public class SerializableWriter {
    
    public static void main(String[] args) throws Exception{
        write();
    }
    
    public static void write() throws Exception{
            Student stu= new Student();
            stu.setField1("aaa111");
            stu.setField2("bbb222");
            ObjectOutputStream objectOutputStream = new ObjectOutputStream(new FileOutputStream("C:/Users/King/Desktop/jx.txt"));
            objectOutputStream.writeObject(stu);
            objectOutputStream.flush();
            objectOutputStream.close();
    }

}

 

SerializableReader.java

package a.b.c;

import java.io.FileInputStream;
import java.io.ObjectInputStream;

public class SerializableReader {
    
    public static void main(String[] args) throws Exception{
        read();
    }
    
    public static void read() throws Exception{
            ObjectInputStream objectInputStream = new ObjectInputStream(new FileInputStream("C:/Users/King/Desktop/jx.txt"));
            Object obj=objectInputStream.readObject();
            Person person=(Person)obj;
            System.out.println(person.getField1());
            System.out.println(person.getField2());
            objectInputStream.close();
    }

}

打印结果

aaa111
bbb222

 

 

总结

•       只要版本号一致,且Student就算删掉field3的属性和方法,仍旧可以把序列化后的Student反序列化成Student.
•       只要版本号一致,且Student  继承自父类 Person,那么就可以把序列化后的Student反序列化成Person.

自己项目经历:

esb_new.jar包中的head多加了一个password属性(这个场景是说添加属性的那个包就是新包)

然后生产上 核心 通过http连接 ESB(esb_old.jar) 去调用 电销(esb_new.jar)回调接口 ,报序列号版本不一致问题, 因为电销提供的回调接口是Spring Invoke远程方法调用,需要依赖请求对象RequestBusinessObjVo,在转对象时会用到序列化头部信息,此时旧包(esb_old.jar)丢了新包(esb_new.jar)需要的属性,所以旧包不能调新包.

但是电销(esb_new.jar)通过http连接 ESB(esb_old.jar)去调代理平台(esb_old.jar) 没报错. 是因为 电销 和ESB是http通信的,而ESB和代理平台此时通过Spring Invoke远程方法调用,仍旧用的是esb_old.jar包所以没有报序列号问号.