改变SpringBoot默认的HttpMessageCoverter

蔚落 2022-02-14 02:49 212阅读 0赞

## 前言 ##

#### [博主github][github] ####

#### [博主个人博客http://blog.healerjean.com][http_blog.healerjean.com] ####

正常情况下我们SpringBoot为我们提供了HttpMessageCorverter用于前后台数据的转化，经常我们会发现返回到前台的对象，字段是NULL，这些NULL其实本不应该返回给前端显示，无疑是增加了前端小哥哥，小姐姐的负担

当然，你能想到的是使用@JsonInclude @JsonJgnore来解决，但是这里呢，使用的是另一个中解析的类

### 1、fastjson依赖 ###

<dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>fastjson</artifactId>
                <version>1.2.15</version>
        </dependency>

### 2、config ###

package com.hlj.config;
    
    import com.alibaba.fastjson.serializer.SerializerFeature;
    import com.alibaba.fastjson.support.config.FastJsonConfig;
    import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
    import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.http.converter.HttpMessageConverter;
    
    import java.nio.charset.Charset;
    
    @Configuration
    public class HttpMessageConverterConfig {
    
        //引入Fastjson解析json，不使用默认的jackson
        @Bean
        public HttpMessageConverters fastJsonHttpMessageConverters() {
            //1、定义一个convert转换消息的对象
            FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
    
            //2、添加fastjson的配置信息
            FastJsonConfig fastJsonConfig = new FastJsonConfig();
    
            SerializerFeature[] serializerFeatures = new SerializerFeature[]{
                    //    输出key是包含双引号
                    SerializerFeature.QuoteFieldNames,
                    //    是否输出为null的字段,若为null 则显示该字段
    //                SerializerFeature.WriteMapNullValue,
                    //    数值字段如果为null，则输出为0
                    SerializerFeature.WriteNullNumberAsZero,
                    //     List字段如果为null,输出为[],而非null
                    SerializerFeature.WriteNullListAsEmpty,
                    //    字符类型字段如果为null,输出为"",而非null
                    SerializerFeature.WriteNullStringAsEmpty,
                    //    Boolean字段如果为null,输出为false,而非null
                    SerializerFeature.WriteNullBooleanAsFalse,
                    //    Date的日期转换器
                    SerializerFeature.WriteDateUseDateFormat,
                    //    循环引用
                    SerializerFeature.DisableCircularReferenceDetect,
            };
    
            fastJsonConfig.setSerializerFeatures(serializerFeatures);
            fastJsonConfig.setCharset(Charset.forName("UTF-8"));
    
            //3、在convert中添加配置信息
            fastConverter.setFastJsonConfig(fastJsonConfig);
    
            //4、将convert添加到converters中
            HttpMessageConverter<?> converter = fastConverter;
    
            return new HttpMessageConverters(converter);
        }
    }

### 3、实体对象 ###

@Data
    @Accessors(chain = true)
    @ApiModel(value = "demo实体类")
    public class DemoEntity {
    
    	private String name;
    
    	private String tmail;
    
    	private Long volumn ;
    
    }

### 4、测试 ###

@GetMapping("get")
        @ResponseBody
        public ResponseBean get(String params){
            try {
                return ResponseBean.buildSuccess(new DemoEntity());
            } catch (AppException e) {
                log.error(e.getMessage(),e);
                return ResponseBean.buildFailure(e.getCode(),e.getMessage());
            } catch (Exception e) {
                log.error(e.getMessage(),e);
                return ResponseBean.buildFailure(e.getMessage());
            }
        }

#### 4.1，如果没有config的情况下 ####

{
     "success": true,
     "result": {
         "name": null,
         "tmail": null,
         "volumn": null
         },
     "message": "",
     "code": "200",
     "date": "1556183337784"
    }

#### 4.2、如果使用了上面的，是很干净的 ####

{
      "code": "200",
      "date": "1556183419997",
      "message": "",
      "result": {},
      "success": true
    }

![ContactAuthor][]

[github]: https://github.com/HealerJean
[http_blog.healerjean.com]: http://HealerJean.github.io
[ContactAuthor]: /images/20220214/507d5e65fe7b446199b434b09ebd1d91.png