基于jackson 多态数据类型处理rest api 业务

jackson 支持多态数据类型处理，基于此特性我们可以实现灵活强大的类型处理，业务规则处理
同时基于此可以实现动态插件化的业务处理

参考使用

• 抽象类型定义
  MyUser

 

package com.dalong;

 

import com.fasterxml.jackson.annotation.JsonAutoDetect;

import com.fasterxml.jackson.annotation.JsonTypeInfo;

 

@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.EXTERNAL_PROPERTY, property = "type")

@JsonAutoDetect(fieldVisibility= JsonAutoDetect.Visibility.PUBLIC_ONLY, getterVisibility= JsonAutoDetect.Visibility.NONE, isGetterVisibility= JsonAutoDetect.Visibility.NONE, setterVisibility= JsonAutoDetect.Visibility.NONE)

public abstract class MyUser<T> {

    public abstract String printVersion();

    public  String getType(){

        return this.getClass().getAnnotation(SourceType.class).value();

    }

    public abstract T instance();

}

SourceType 注解定义

package com.dalong;

 

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.TYPE})

public @interface SourceType {

    String value();

    String label() default "";

    String uiConfig() default "";

    boolean configurable() default true;

    boolean listable() default true;

    boolean externalQuerySupported() default false;

}

• 子类
  FirstMyUser

 

package com.dalong;

import java.util.UUID;

@SourceType(value ="FirstMyUser-dalongdemo")

public class FirstMyUser extends MyUser<FirstMyUser> {

    public String name;

    public String classType;

    @Override

    public String printVersion() {

        return UUID.randomUUID().toString();

    }

    @Override

    public FirstMyUser instance() {

        return this;

    }

}

SecondMyUser

package com.dalong;

import java.util.UUID;

@SourceType(value ="SecondMyUser-dalongdemoapp")

public class SecondMyUser extends MyUser<SecondMyUser> {

    public String name;

    public String classType;

 

    @Override

    public String printVersion() {

        return UUID.randomUUID().toString();

    }

 

    @Override

    public SecondMyUser instance() {

        return this;

    }

}

 

 

• 使用

package com.dalong;

 

import com.fasterxml.jackson.core.JsonProcessingException;

import com.fasterxml.jackson.databind.ObjectMapper;

import com.fasterxml.jackson.databind.jsontype.NamedType;

import java.lang.reflect.InvocationTargetException;

 

public class App {

   static   ObjectMapper objectMapper = new ObjectMapper();

    public static void main(String[] args) throws JsonProcessingException, NoSuchMethodException, InvocationTargetException, IllegalAccessException {

        objectMapper.registerSubtypes(new NamedType(FirstMyUser.class, "dalongdemo"));

        objectMapper.registerSubtypes(new NamedType(SecondMyUser.class, "dalongdemoapp"));

        FirstMyUser bean = new FirstMyUser();

        bean.name="dalong";

        bean.classType="testapp";

        String s = objectMapper.writeValueAsString(bean);

        System.out.println(s);

        SecondMyUser bean2 = new SecondMyUser();

        bean2.name="dalong2";

        bean2.classType="testapp2";

        String s2 = objectMapper.writeValueAsString(bean2);

        System.out.println(s2);

        MyUser myUser=  objectMapper.readValue(s,MyUser.class);

        MyUser myUser2=  objectMapper.readValue(s2,MyUser.class);

        System.out.println(myUser.getType());

        System.out.println(myUser2.getType());

        Object ob= myUser2.instance();

        Object result = ob.getClass().getMethod("getType",null).invoke(ob,null);

        System.out.println(result.toString());

    }

}

• 效果

 

 

说明

集成rest 的玩法，可以基于一个通用的rest 接口定义，基于不同的类型，使用如果类似的方法，同时集成上plugin 处理机制就可以灵活的控制业务数据处理了
参考如下示意集成模式

 

 

参考资料

https://www.baeldung.com/jackson-annotations
https://fasterxml.github.io/jackson-annotations/javadoc/2.4/com/fasterxml/jackson/annotation/JsonTypeInfo.html