transient修饰的变量可以被序列化吗？

迈不过友情╰ 2022-01-19 20:25 223阅读 0赞

看到网上很多博客都是写到transient修饰的变量不可以被序列化， 实际上其变量可以被序列化，《Java编程思想》上写的很清楚。

**事实证明：看博客不如看书（看经典书籍），看书不如自己码代码验证**

代码是借鉴别人的，为了验证问题，直接上代码：

import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.ObjectInputStream;
    import java.io.ObjectOutputStream;
    import java.io.Serializable;
    
    public class PasswordFormat implements Serializable {
        /** * */
        private static final long serialVersionUID = 1L;
        private String name;
        private transient String password;
        public PasswordFormat(String name, String password) {
            this.name = name;
            this.password = password;
        }
        public PasswordFormat() {
        }
        public String getName() {
            return name;
        }
        public void setName(String name) {
            this.name = name;
        }
        public String getPassword() {
            return password;
        }
        public void setPassword(String password) {
            this.password = password;
        }
        private void writeObject(ObjectOutputStream oos) throws IOException {
        //重写以下两个方法，完成序列化时password的加密和解密
            oos.defaultWriteObject();
            char a[]=this.password.toCharArray();
            String str="";
            for(int i=0;i<a.length;i++){
                a[i]+=i;
                str+=a[i];
            }//各项加i再逆置；
            StringBuilder sb = new StringBuilder(str);
            oos.writeObject(sb.reverse().toString());
        }
        private void readObject(ObjectInputStream ois) throws ClassNotFoundException, IOException {
            ois.defaultReadObject();
            String str = (String) ois.readObject();
            System.out.println("解密后：" + str);
            StringBuilder sb = new StringBuilder(str);
            sb.reverse();
            char a[]=sb.toString().toCharArray();
            str="";
            for(int i=0;i<a.length;i++){
                a[i]-=i;
                str+=a[i];
            }
            this.password = str;
        }
    
        @Override
        public String toString() {
            return "PasswordFormat [name=" + name + ", password=" + password + "]";
        }
        public static void serializeTemp(PasswordFormat ob,File file){
            try(
                    ObjectOutputStream oos=new ObjectOutputStream(new FileOutputStream(file));
                    ObjectInputStream ois=new ObjectInputStream(new FileInputStream(file));
                    ){
                oos.writeObject(ob);
                oos.flush();
                System.out.println((PasswordFormat)ois.readObject());
            }catch(IOException | ClassNotFoundException e){
                e.printStackTrace();
            }
        }
        public static void main(String[] args) {
            PasswordFormat pf=new PasswordFormat("xcw","xcw12345678");
            File file=new File("./yj.txt");
            PasswordFormat.serializeTemp(pf,file);
        }
    }
    复制代码

上图可以看到，只要重写writeObject和readObject，

*  非transinent修饰的变量使用defaultWriteObject()和defaultReadObject()进行序列化和反序列化
 *  transient修饰的变量必须手动使用writeObject()和readObject()进行序列化和反序列化