springboot 请求结果json手动转换null

你的名字 2022-10-06 04:56 161阅读 0赞

> 发现springboot框架返回json给前端时，前端要求需要对null等做处理，json版本不同转出的效果不一样，这里手动重写转换字符

*  新增一个配置类，重写json转换null问题
    
        @Configuration
          public class ResultConfig { 
          
              @Bean
              public MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter() { 
                  MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter = new MappingJackson2HttpMessageConverter();
                  List<MediaType> supported = new ArrayList<>();
                  supported.add(MediaType.APPLICATION_JSON_UTF8);
                  mappingJackson2HttpMessageConverter.setSupportedMediaTypes(supported);
          
                  // JsonMapper
                  ObjectMapper objectMapper = new ObjectMapper();
          
                  // null值的处理，必须要放在第一步，否则会将下面的日期格式化覆盖掉
                  // null ==> ""
                  objectMapper.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>() { 
                      @Override
                      public void serialize(Object value, JsonGenerator gen, SerializerProvider serializers) throws IOException { 
                          gen.writeString("");
                      }
                  });
          
          
                  mappingJackson2HttpMessageConverter.setObjectMapper(objectMapper);
                  return mappingJackson2HttpMessageConverter;
              }
          
          // @Bean
          // public ObjectMapper objectMapper() { 
          // ObjectMapper objectMapper = new ObjectMapper();
          // objectMapper.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>() { 
          // @Override
          // public void serialize(Object paramT, JsonGenerator paramJsonGenerator,
          // SerializerProvider paramSerializerProvider) throws IOException { 
          // //设置返回null转为 空字符串""
          // paramJsonGenerator.writeString("");
          // }
          // });
          // return objectMapper;
          // }
          }