项目集成 FastJson 解析框架，一般都会添加一个配置文件，如下：

@Configuration

public class CustomFastJsonConfig {

@Bean

FastJsonHttpMessageConverter fastJsonHttpMessageConverter(){

//1.需要定义一个convert转换消息的对象 FastJsonHttpMessageConverter converter = new FastJsonHttpMessageConverter();

//2:添加fastJson的配置信息 FastJsonConfig fastJsonConfig = new FastJsonConfig();

fastJsonConfig.setSerializerFeatures(

// 是否输出值为null的字段,默认为false SerializerFeature.WriteMapNullValue,

// 将Collection类型字段的字段空值输出为[] SerializerFeature.WriteNullListAsEmpty,

// 将字符串类型字段的空值输出为空字符串 SerializerFeature.WriteNullStringAsEmpty,

// 将数值类型字段的空值输出为0 SerializerFeature.WriteNullNumberAsZero,

//Boolean字段如果为null,输出为false,而非null SerializerFeature.WriteNullBooleanAsFalse,

//SerializerFeature.WriteDateUseDateFormat, //枚举字段输出为枚举值 SerializerFeature.WriteEnumUsingToString,

// 禁用循环引用 SerializerFeature.DisableCircularReferenceDetect);

//这个日期格式是全局格式：yyyy-MM-dd HH:mm:ss fastJsonConfig.setDateFormat("yyyy-MM-dd HH:mm:ss");

fastJsonConfig.setCharset(StandardCharsets.UTF_8);

//3处理中文乱码问题 List fastMediaTypes = new ArrayList<>();

fastMediaTypes.add(MediaType.APPLICATION_JSON);

//4.在convert中添加配置信息. converter.setSupportedMediaTypes(fastMediaTypes);

converter.setFastJsonConfig(fastJsonConfig);

return converter;

}

}

但是，当 Spring Cloud 微服务项目使用 Feign 的时候，有一个比较坑的地方，就是，Feign 并不共用 Spring MVC 的消息转换器链，而且它默认使用的是 Jackson JSON 解析库，而项目使用的又是 FastJson，这会导致混乱，甚至出现序列化/反序列化错误。

就比如上边这个配置，A 应用通过 Feign 调用 B 应用的搜索接口，接口参数是一个实体对象，其中实体对象有一个 Date 类型的时间属性参数 downDate，那么，由于上边配置的日期格式是：yyyy-MM-dd HH:mm:ss，在通过 Feign 调用的时候，就会产生一个异常：

{"timestamp":"2020-03-29T03:54:55.014+0000","status":400,"error":"Bad Request","message":"JSON parse error:

Cannot deserialize value of type `java.util.Date` from String \"2020-03-03 00:00:00\":

not a valid representation (error: Failed to parse Date value '2020-03-03 00:00:00':

Cannot parse date \"2020-03-03 00:00:00\":

while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSSZ', parsing fails (leniency? null));

nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException:

Cannot deserialize value of type `java.util.Date` from String \"2020-03-03 00:00:00\":

not a valid representation (error: Failed to parse Date value '2020-03-03 00:00:00':

Cannot parse date \"2020-03-03 00:00:00\":

while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSSZ', parsing fails (leniency? null)) at [Source: (PushbackInputStream);

line: 1, column: 154] (through reference chain: com.kangaroohy.entity.bo.SearchBO[\"downDate\"])","path":"/api/search"}

因此，需要为 Feign 单独配置 FastJson，将原来的转换器替换成 FastJson 的，具体配置如下：

import com.alibaba.fastjson.serializer.SerializerFeature;

import com.alibaba.fastjson.support.config.FastJsonConfig;

import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;

import feign.codec.Encoder;

import org.springframework.beans.factory.ObjectFactory;

import org.springframework.boot.autoconfigure.http.HttpMessageConverters;

import org.springframework.cloud.openfeign.support.SpringEncoder;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.http.MediaType;

import org.springframework.http.converter.HttpMessageConverter;

import java.util.ArrayList;

import java.util.List;

/*** @desc: feign配置* @author: kangaroohy* @create: 2020/03/26*/

@Configuration

public class FeignClientConfig {

@Bean

public Encoder feignEncoder(){

return new SpringEncoder(feignHttpMessageConverter());

}

private ObjectFactory feignHttpMessageConverter() {

final HttpMessageConverters httpMessageConverters = new HttpMessageConverters(createFastJsonConverter());

return () -> httpMessageConverters;

}

private HttpMessageConverter createFastJsonConverter(){

FastJsonHttpMessageConverter fastJsonConverter = new FastJsonHttpMessageConverter();

List supportedMediaTypes = new ArrayList<>();

supportedMediaTypes.add(MediaType.APPLICATION_JSON);

supportedMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);

supportedMediaTypes.add(MediaType.APPLICATION_ATOM_XML);

supportedMediaTypes.add(MediaType.APPLICATION_FORM_URLENCODED);

supportedMediaTypes.add(MediaType.APPLICATION_OCTET_STREAM);

supportedMediaTypes.add(MediaType.APPLICATION_PDF);

supportedMediaTypes.add(MediaType.APPLICATION_RSS_XML);

supportedMediaTypes.add(MediaType.APPLICATION_XHTML_XML);

supportedMediaTypes.add(MediaType.APPLICATION_XML);

supportedMediaTypes.add(MediaType.IMAGE_GIF);

supportedMediaTypes.add(MediaType.IMAGE_JPEG);

supportedMediaTypes.add(MediaType.IMAGE_PNG);

supportedMediaTypes.add(MediaType.TEXT_EVENT_STREAM);

supportedMediaTypes.add(MediaType.TEXT_HTML);

supportedMediaTypes.add(MediaType.TEXT_MARKDOWN);

supportedMediaTypes.add(MediaType.TEXT_PLAIN);

supportedMediaTypes.add(MediaType.TEXT_XML);

fastJsonConverter.setSupportedMediaTypes(supportedMediaTypes);

FastJsonConfig fastJsonConfig = new FastJsonConfig();

fastJsonConfig.setSerializerFeatures(

// 是否输出值为null的字段,默认为false SerializerFeature.WriteMapNullValue,

// 将Collection类型字段的字段空值输出为[] SerializerFeature.WriteNullListAsEmpty,

// 将字符串类型字段的空值输出为空字符串 SerializerFeature.WriteNullStringAsEmpty,

// 将数值类型字段的空值输出为0 SerializerFeature.WriteNullNumberAsZero,

//Boolean字段如果为null,输出为false,而非null SerializerFeature.WriteNullBooleanAsFalse,

//SerializerFeature.WriteDateUseDateFormat, //枚举字段输出为枚举值 SerializerFeature.WriteEnumUsingToString,

// 禁用循环引用 SerializerFeature.DisableCircularReferenceDetect);

fastJsonConverter.setFastJsonConfig(fastJsonConfig);

return fastJsonConverter;

}

}

此时，就不会发生上述的报错了。

特此记录。