transient关键字详解

作用

1，一旦变量被transient修饰，变量将不再是对象持久化的一部分，该变量内容在序列化后无法获得访问。 
2，transient关键字只能修饰变量，而不能修饰方法和类。注意，本地变量是不能被transient关键字修饰的。变量如果是用户自定义类变量，则该类需要实现Serializable接口。 
3，一个静态变量不管是否被transient修饰，均不能被序列化。 

请看代码

//实体类（必须实现Serializable接口，才能被序列化）
public class Resume implements Cloneable,Serializable{
    private static final long serialVersionUID = 1L;

    private String name;
    private static String sex;
    transient private String age;
    private WorkExperience workExperience;

    public WorkExperience getWorkExperience() {
        return workExperience;
    }

    public void setWorkExperience(WorkExperience workExperience) {
        this.workExperience = workExperience;
    }

    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 String getAge() {
        return age;
    }

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

    public void dispaly(){
        System.out.println("姓名："+name+"	年龄："+age+"	性别："+sex);
//        System.out.println("工作经历："+workExperience.getWorkDate()+"	"+workExperience.getCompany());
    }

    public Object clone(){
        try {
            Resume resume = (Resume)super.clone();
            return resume;
        }catch (Exception e){
            return null;
        }

    }

}


public class MainTest2 {
    public static void main(String[] args){

        try {
//            序列化Resume
            Resume resume = new Resume();
            resume.setName("哈哈");
            resume.setSex("男");
            resume.setAge("20");
            resume.dispaly();
            ObjectOutputStream outputStream = new ObjectOutputStream(new FileOutputStream("D:\resume.txt"));
            outputStream.writeObject(resume);
            outputStream.close();
        }catch (Exception e){
            e.printStackTrace();
        }


    }
}
//输出结果
姓名：哈哈	年龄：20	性别：男

反序列化

public class MainTest2 {
    public static void main(String[] args){

        try {
//            序列化Resume
            Resume resume = new Resume();
//            resume.setName("哈哈");
//            resume.setSex("男");
//            resume.setAge("20");
//            resume.dispaly();
//            ObjectOutputStream outputStream = new ObjectOutputStream(new FileOutputStream("D:\resume.txt"));
//            outputStream.writeObject(resume);
//            outputStream.close();

            //改变sex（根据结果可见sex未被序列化，而是直接从内存中读取）
            resume.setSex("女");

            //反序列化
            ObjectInputStream inputStream = new ObjectInputStream(new FileInputStream("D:\resume.txt"));
            Resume resume1 = (Resume) inputStream.readObject();
            resume1.dispaly();
        }catch (Exception e){
            e.printStackTrace();
        }


    }
}
//结果
姓名：哈哈	年龄：null	性别：女

　根据结果可知age字段被transient修饰未能序列化成功，而sex反序列化之前改变了值，所以标明也未被序列化。