（一）关键字--transient

一、transient关键字

transient：字面意思临时短暂；

在java中修饰变量表示只存在于内存中，当序列化至磁盘时不保存，如TreeMap中就有此关键字使用；

测试代码

package com.sjjg.rbtree;

import java.io.Serializable;

public class Person implements Serializable{

    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private  Integer id;
    private transient String name;//此变量在在序列化时不会保存值
    private  Integer sex;
    public Person() {
        super();
        // TODO Auto-generated constructor stub
    }
    public Person(Integer id, String name, Integer sex) {
        super();
        this.id = id;
        this.name = name;
        this.sex = sex;
    }
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getSex() {
        return sex;
    }
    public void setSex(Integer sex) {
        this.sex = sex;
    }

    @Override
    public String toString() {
        return "Person [id=" + id + ", name=" + name + ", sex=" + sex + "]";
    }
}

测试效果

package com.sjjg.rbtree;

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 MainTest {

    public static void main(String[] args) throws FileNotFoundException, IOException, ClassNotFoundException {
//      xlh();
        fxlh();
    }
    public static void fxlh() throws IOException, IOException,
    ClassNotFoundException{
        //序列化
        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(
        "d:/data.txt"));
        Person p = new Person(25, "zhangsan", 1);
        oos.writeObject(p);
        oos.close();
        //反序列化
        ObjectInputStream ois = new ObjectInputStream(new FileInputStream(
                "d:/data.txt"));
        Person p1 = (Person) ois.readObject();
        System.out.println(p1);          
        //Person [id=25, name=null, sex=1]
        ois.close();

        /**未使用 transient修饰name变量时
         *  sr com.sjjg.rbtree.Person       
 L idt Ljava/lang/Integer;L namet Ljava/lang/String;L sexq ~ 
xpsr java.lang.Integer鉅亣8 
I valuexr java.lang.Number啲?斷?  xp   t zhangsansq ~    

         使用 transient修饰name变量时
         *  sr com.sjjg.rbtree.Person       
 L idt Ljava/lang/Integer;L sexq ~ 
xpsr java.lang.Integer鉅亣8 
I valuexr java.lang.Number啲?斷?  xp   sq ~    

         */
    }

}

对象序列化讲解：
https://www.cnblogs.com/dongguacai/p/5721056.html