原创

jackson 空值NULL转成空串输出

需求背景

原始输出的JSON

{
                "name": "age",
                "label": "年龄",
                "type": "Integer",
                "defaultValue": null,
                "act": "InOut"
  }

需要转换成

{
                "name": "age",
                "label": "年龄",
                "type": "Integer",
                "defaultValue": "",
                "act": "InOut"
  }

实现方法

增加转换器

protected void writeObjectToJsonWithNull(HttpServletResponse resp,Object obj) throws ServletException, IOException{
   resp.setHeader("Access-Control-Allow-Origin", "*");
   resp.setContentType("text/json");
   resp.setCharacterEncoding("UTF-8");
   ObjectMapper mapper=new ObjectMapper();

   mapper.getSerializerProvider().setNullValueSerializer(
   new JsonSerializer<Object>() {
      @Override
      public void serialize(Object param, JsonGenerator jsonGenerator,
                       SerializerProvider paramSerializerProvider) throws IOException {
         jsonGenerator.writeString("");
      }
   });
   mapper.setSerializationInclusion(Inclusion.ALWAYS);
   mapper.configure(SerializationConfig.Feature.WRITE_DATES_AS_TIMESTAMPS,false);
   mapper.setDateFormat(new SimpleDateFormat(Configure.getDateFormat()));
   OutputStream out = resp.getOutputStream();
   try {
      mapper.writeValue(out, obj);
   } finally {
      out.flush();
      out.close();
   }
}

正文到此结束