java序列化对象，根据不同配置动态改变属性名

Answer 1

java序列化对象，根据不同配置动态改变属性名

使用场景：自己项目对接多个外部系统，各个外部系统使用的字段并没有统一，所以要根据不同系统动态的输出序列化数据，使适应各个系统的要求

实现方式

使用自定义注解和fastjson实现需求

fastjson的NameFilter的作用：序列化时，属性名变成自己指定的名称

实现过程自定义注解一：MyParamNamepackage xin.yangshuai.cipher.json;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;/** * MyParamName * * @author shuai * @date 2021/3/23 */@Retention(RetentionPolicy.RUNTIME)@Target({ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER})public @interface MyParamName {String value() default "";NameEle[] names() default {};}

value、names都是非必填

value：默认序列化的名称

names：自定义注解二，数组形式

自定义注解二：NameElepackage xin.yangshuai.cipher.json;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;/** * NameEle * * @author shuai * @date 2021/3/24 */@Retention(RetentionPolicy.RUNTIME)@Target({ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER})public @interface NameEle {String id();String value();}

id：唯一标识，确定序列化后的属性名

value：定义序列化后的属性名

手写MyNameFilter，实现fastjson的NameFilterpackage xin.yangshuai.cipher.json;import com.alibaba.fastjson.serializer.NameFilter;import java.lang.reflect.Field;/** * MyNameFilter * * @author shuai * @date 2021/3/23 */public class MyNameFilter implements NameFilter {private String id;public MyNameFilter() {}public MyNameFilter(String id) {this.id = id;}@Overridepublic String process(Object o, String name, Object value) {try {Field field = o.getClass().getDeclaredField(name);MyParamName myParamName = field.getDeclaredAnnotation(MyParamName.class);NameEle[] nameEles = myParamName.names();String defaultName = myParamName.value();if (nameEles.length == 0 && defaultName.length() > 0) {return defaultName;}for (NameEle n : nameEles) {if (id.equals(n.id())) {return n.value();}}} catch (Exception e) {return name;}return name;}}

构造方法传递id属性的值，与自定义注解二的id进行匹配，匹配成功则使用对应的属性名

实体类，属性上添加自定义注解package xin.yangshuai.cipher.json;import com.alibaba.fastjson.JSON;/** * Person * * @author shuai * @date 2021/3/23 */public class Person {@MyParamName(names = {@NameEle(id = "ln", value = "i_d"),@NameEle(id = "jl", value = "_id")})private String id;@MyParamName("NAME")private String name;private String age;public String getId() {return id;}public void setId(String id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getAge() {return age;}public void setAge(String age) {this.age = age;}@Overridepublic String toString() {return "Person{" +"id='" + id + '\'' +", name='" + name + '\'' +", age='" + age + '\'' +'}';}}

运行主方法测试public static void main(String[] args) {Person person = new Person();person.setAge("18");person.setId("001");person.setName("张三");String s = JSON.toJSONString(person, new MyNameFilter("jl"));System.out.println(s);String s1 = JSON.toJSONString(person, new MyNameFilter("ln"));System.out.println(s1);}

结果为：

{"age":"18","_id":"001","NAME":"张三"} {"age":"18","i_d":"001","NAME":"张三"}

参考

# java序列化对象，根据不同配置动态改变属性名

原文：https://juejin.cn/post/7101517823695912990