乾了這杯Java之transient關鍵字

看源碼的時候,發現transient這個關鍵字,不甚理解,查找資料發現:不被序列化

疑問:

• 靜態變量是否是不被序列化？

public class User implements Serializable {

    private static final long serialVersionUID = 2877054094045568710L;

    private String username;
    
    private transient String password;
    
    private static int age;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
    
    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        User.age = age;
    }

    public static void main(String[] args) {
        User user = new User();
        user.setUsername("imeng");
        user.setPassword("123456");
        user.setAge(22);
        
        try {           
            ObjectOutputStream os = new ObjectOutputStream(
                    new FileOutputStream("/Users/imeng/Desktop/user.txt"));
            os.writeObject(user);
            os.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        
        //序列號後改變Static的值
        user.setAge(100);
        
        ObjectInputStream oi;
        try {
            oi = new ObjectInputStream(new FileInputStream("/Users/imeng/Desktop/user.txt"));
            User readUser = (User) oi.readObject();
            System.out.println("username:" + readUser.getUsername());
            System.out.println("transient關鍵字password:" + readUser.getPassword());
            System.out.println("靜態變量age:" + readUser.getAge());
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
}

username:imeng
password:null
age:100

結論:

• transient關鍵字能夠阻止序列化
• 序列號並不保存靜態變量