spring cloud feign jackson 枚举json互转枚举json序列化/反序列化

ゞ浴缸里的玫瑰 2022-12-29 11:18 403阅读 0赞

## 问题描述 ##

接口返回对象中的一个属性是枚举类型，并且是以json格式输出的，如下：

"status": { 
                  "name": "NOT_STARTED",
                  "desc": "待开始",
                  "code": 0
               }

该接口通过前端或者postmain正常调用都没问题，但是。。。内部服务通过feign调用就会出现异常，如下

feign.codec.DecodeException: Error while extracting response for type 
    [com.xxxx.cloud.common.response.Result<com.xxxx.omall.marketing.dto.res.MarketingActivityRes>] 
    and content type [application/json;charset=UTF-8]; nested exception is org.springframework.
    http.converter.HttpMessageNotReadableException: JSON parse error: Cannot deserialize 
    instance of `com.xxxx.omall.marketing.dto.enums.FlashPtsStatusEnum` out of START_OBJECT 
    token; nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException:
    Cannot deserialize instance of `com.xxxx.omall.marketing.dto.enums.FlashPtsStatusEnum` 
    out of START_OBJECT token
    at [Source: (ByteArrayInputStream); line: 1, column: 233] (through reference chain: 
    com.xxxx.cloud.common.response.Result["data"]->com.xxxx.omall.marketing.dto.res.MarketingActivityRes
    ["flashPromotions"]->java.util.ArrayList[0]->com.xxxx.omall.marketing.dto.res.FlashPromotionRes["status"])

以下是解决方案

## 枚举基类 ##

import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
     
    @JsonDeserialize(using = BaseEnumDeserializer.class) 
    public interface BaseEnum extends Serializable{ 
    	/** * 调用枚举的this.name() * @return */
    	String getCode();
    	
    	static <E extends Enum<E> & BaseEnum> E valueOf(String enumCode,Class<E> clazz) { 
    		E enumm = Enum.valueOf(clazz, enumCode);
    		return enumm;
    	}
    	
    }

## 定义自己的枚举并且实现 BaseEnum ##

import com.fasterxml.jackson.annotation.JsonFormat;
     
    /** * 通用状态 * @author xxx * 2018年3月26日 上午9:53:51 */
    @JsonFormat(shape = JsonFormat.Shape.OBJECT)
    public enum CommonStatus implements BaseEnum{ 
    	CREATE("新建"),
    	ENABLED("启用"),
    	DISABLED("禁用"),
    	DELETE("删除")
    	;
    	
    	private CommonStatus(String displayName) { 
    		this.displayName = displayName;
    	}
    	
    	private String displayName;
    	
    	public String getCode(){ 
    		return this.name();
    	}
    	
    	public String getDisplayName() { 
    		return this.displayName;
    	}
     
     
    }

## 自定义枚举转换器 ##

import org.springframework.beans.BeanUtils;
     
    import com.fasterxml.jackson.annotation.JsonFormat;
    import com.fasterxml.jackson.annotation.JsonFormat.Shape;
    import com.fasterxml.jackson.core.JsonParser;
    import com.fasterxml.jackson.core.JsonProcessingException;
    import com.fasterxml.jackson.databind.DeserializationContext;
    import com.fasterxml.jackson.databind.JsonDeserializer;
    import com.fasterxml.jackson.databind.JsonNode;
     
    /** * 解决 spring cloud json 转枚举问题 * @author xxxx * 2018年6月13日 下午5:30:02 */
    public class BaseEnumDeserializer extends JsonDeserializer<BaseEnum>{ 
     
    	@Override
    	@SuppressWarnings("unchecked")
    	public BaseEnum deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException, JsonProcessingException { 
    		JsonNode node = jp.getCodec().readTree(jp);
    		String currentName = jp.currentName();
    		Object currentValue = jp.getCurrentValue();
    		@SuppressWarnings("rawtypes")
    		Class findPropertyType = BeanUtils.findPropertyType(currentName, currentValue.getClass());
    		JsonFormat annotation = (JsonFormat) findPropertyType.getAnnotation(JsonFormat.class);
    		BaseEnum valueOf;
    		if(annotation == null || annotation.shape() != Shape.OBJECT) { 
    			valueOf = BaseEnum.valueOf(node.asText(), findPropertyType);
    		}else { 
    			valueOf = BaseEnum.valueOf(node.get("code").asText(),findPropertyType);
    		}
    		return valueOf;
    	}
     
     
    }

## 注册转换器 ##

import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
    import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
    import org.springframework.cloud.openfeign.EnableFeignClients;
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.ApplicationListener;
    import org.springframework.context.event.ContextRefreshedEvent;
     
    import com.fasterxml.jackson.databind.JsonDeserializer;
    import com.fasterxml.jackson.databind.ObjectMapper;
    import com.fasterxml.jackson.databind.module.SimpleModule;
    import com.replace_common.mproject.core.enums.BaseEnum;
    import com.replace_common.mproject.core.enums.BaseEnumDeserializer;
     
    @SpringBootApplication  
    @EnableDiscoveryClient  
    @EnableCircuitBreaker  
    @EnableFeignClients   //启动远程调用,调用其他项目的接口
    public class ComputeServiceApplication implements ApplicationListener<ContextRefreshedEvent> { 
    	
    	
    	private boolean isExecut;
    	
    	@Override
    	public void onApplicationEvent(ContextRefreshedEvent event) { 
    		if(!isExecut) { 
    			ApplicationContext applicationContext = event.getApplicationContext();
    			//注册转换器
    			SimpleModule module = new SimpleModule();
    			JsonDeserializer<BaseEnum> deserialize = new BaseEnumDeserializer();
    			module.addDeserializer(BaseEnum.class, deserialize);  
    			ObjectMapper bean = applicationContext.getBean(ObjectMapper.class);
    			bean.registerModule(module);
    		}
    		isExecut=true;
    	}
     
    	public static void main(String[] args) {   
    		SpringApplication.run(ComputeServiceApplication.class, args);  
    	}  
     
    }

然后spring cloud feign 内部调用 之间交互的实体类中的枚举就可以自动正常转换了