【Java注解】自定义注解的简单demo

需求场景

对于特定字段进行脱敏

实现步骤

首先创建注解@interface

 1 import java.lang.annotation.ElementType;
 2 import java.lang.annotation.Retention;
 3 import java.lang.annotation.RetentionPolicy;
 4 import java.lang.annotation.Target;
 5 
 6 @Retention(RetentionPolicy.RUNTIME)
 7 @Target(ElementType.FIELD)
 8 public @interface DesenStr {
 9 
10 }

其次创建注解操作的类

import java.lang.reflect.Field;

public class AnnotationClass {

    public Object parse(Object o) {
        Class<?> mClass = null;
        Object o1 = o;
        try {
            mClass = o.getClass();
            Field[] fields = mClass.getDeclaredFields();
            for (Field field : fields) {
                if (field.isAnnotationPresent(DesenStr.class)) {
                    field.setAccessible(true);

                    String s = String.valueOf(field.get(o1));
                    String replace = StringUtil.desen(s.trim());// 脱敏
                    field.set(o1, replace);
                }
            }
        } catch (IllegalAccessException e) {
            e.printStackTrace();// 此处可自定义打印日志
        }
        return o1;
    }
}

有的小伙伴需要明确替换的char，可以用

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface DesenStr {

    String source() default "";

    String target() default "";
}

import com.dxinfor.mini.ebill.utils.StringUtil;

import java.lang.reflect.Field;

public class AnnotationClass {

    public Object parse(Object o) {
        Class<?> mClass = null;
        Object o1 = o;
        try {
            mClass = o.getClass();
            Field[] fields = mClass.getDeclaredFields();
            for (Field field : fields) {
                if (field.isAnnotationPresent(DesenStr.class)) {
                    field.setAccessible(true);
                    DesenStr annotation = field.getAnnotation(DesenStr.class);
                    String source = annotation.source();// 待匹配
                    String target = annotation.target();// 替换为

                    String s = String.valueOf(field.get(o1));
                    String replace = s.replace(source,target);
                    field.set(o1, replace);
                }
            }
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        return o1;
    }
}

随后在需要替换的成员变量上加上注解 @DesenStr

@Data
@AllArgsConstructor
@NoArgsConstructor
public class UserInfo{
    @DesenStr
    private String userId;
    private String userName;
}

再在使用的地方调用parse方法进行脱敏（此处可以写成AOP）

为了方便就暂时用@Test演示

@Test
void parse(){
    UserInfo userInfo= new UserInfo ("1328223342","张三");
    System.out.println(userInfo);// 1328223342 张三
    Object parseObject = new AnnotationClass().parse(userInfo);
    if(parseObject instanceof UserInfo){
        UserInfo newUserInfo = (UserInfo) parseObject;
        System.out.println(newUserInfo);// 132****342 张三
    }
}