Springboot去掉@RequestBody中字符串类型值的前后空格

tanθ

2018-07-12

Coding / Spring-Boot

改造MappingJackson2HttpMessageConverter

前言

项目组提出要求，Springboot项目中，@ResquestBody标记的bean传入的字符串类型的值要去掉前后空格

实现

因为项目默认使用 MappingJackson2HttpMessageConverter 作为 Json转换器，于是乎重写一些方法做文章，具体实现如下：

@EnableWebMvc
@Configuration
public class WebConfig implements WebMvcConfigurer{
  //... 省略重写的其他方法

  @Override
  public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
   super.configureMessageConverters(converters);
   //对应无法直接返回String类型
   converters.add(0, new MappingJackson2HttpMessageConverter(){
           @Override
           public ObjectMapper getObjectMapper() {
               super.getObjectMapper().setSerializationInclusion(JsonInclude.Include.NON_NULL);
               return super.getObjectMapper();
           }

           /**
           * 重写read方法，然后做去掉前后空格处理，重新转换成object
           * @param type
           * @param contextClass
           * @param inputMessage
           * @return
           * @throws IOException
           * @throws HttpMessageNotReadableException
           */
           @Override
           public Object read(Type type, Class<?> contextClass, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException {
              Object object = super.read(type, contextClass, inputMessage);
              String json = JSONObject.toJSONString(object);
              Map<String,Object> map = (Map<String, Object>) JSONObject.parse(json);

              Set<Map.Entry<String, Object>> entrySet = map.entrySet();

              Map<String, Object> removeSpaceMap = Maps.newHashMap();
              for (Map.Entry<String, Object> entry : entrySet){
                  if (entry.getValue() instanceof String){
                      removeSpaceMap.put(entry.getKey(), ((String) entry.getValue()).trim());
                  }else {
                      removeSpaceMap.put(entry.getKey(),entry.getValue());
                  }
              }
              Gson gson = new Gson();

              String removeSpaceJson = JSON.toJSONString(removeSpaceMap);
              return gson.fromJson(removeSpaceJson, type);
          }
       });
  }
}

但是上面的代码经过各种测试发现一个问题，Gson在处理Integer，Long非浮点型的数值类型时候，自动转换为Double来处理，这导致后续代码做一些数据转换的时候会出现问题，因为Gson内部在处理数据类型都当成Number类型，可以读一下源码，这样需要做如下的改动：

/**
 *
 * @param type
 * @param contextClass
 * @param inputMessage
 * @return
 * @throws IOException
 * @throws HttpMessageNotReadableException
 */
@Override
public Object read(Type type, Class<?> contextClass, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException {
    Object object = super.read(type, contextClass, inputMessage);
    String json = JSONObject.toJSONString(object);
    Map<String,Object> map = (Map<String, Object>) JSONObject.parse(json);

    Set<Map.Entry<String, Object>> entrySet = map.entrySet();

    Map<String, Object> removeSpaceMap = Maps.newHashMap();
    for (Map.Entry<String, Object> entry : entrySet){
        if (entry.getValue() instanceof String){
            removeSpaceMap.put(entry.getKey(), ((String) entry.getValue()).trim());
        }else {
            removeSpaceMap.put(entry.getKey(),entry.getValue());
        }
    }
    String removeSpaceJson = JSON.toJSONString(removeSpaceMap);
    return JSONObject.parseObject(removeSpaceJson, type);

    //注释掉Gson，转换默认将Integer，Long等转换成Double，内部处理看作Number
    /*Gson gson = new Gson();
    return gson.fromJson(removeSpaceJson, type);*/
}

以为这样就结束了吗？哈哈，没有… 😒

以上我们传入的都是正常的JsonObject，比如这种格式的数据

{
    "commonName":"test2",
    "ver":1,
    "certificateRootType":"Z200",
    "expiredDate":"2118-01-01",
    "certificateName":"税务登记证 。",
    "commonCode":"suibian",
    "updateTime":"2018-07-12 13:09:14",
    "perpetual":2,
    "certificateNo":"11111111",
    "certificateTypeName":"税务登记证",
    "imgInfoVOList":[
        {
            "url":"https://www.a.b.c/a.jpg"
        },
        {
            "url":"https://www.a.b.c/b.jpg"
        }
    ],
    "producerType":1,
    "createTime":"2018-07-12 13:09:14",
    "supplier":1043,
    "id":5016,
    "startDate":"2018-01-01",
    "certificateType":"Z202"
}

但是要有这种格式的数据

[
    {
        "roleId":212,
        "name":"上帝视角"
    },
    {
        "roleId":212,
        "name":"上帝视角"
    },
    {
        "roleId":212,
        "name":"上帝视角"
    }
]

如果是下面这种格式的，我们解析的时候就会报转换错误，所以针对下面JsonArray类型的数据，我们需要做特殊处理：

/**
 *
 * @param type
 * @param contextClass
 * @param inputMessage
 * @return
 * @throws IOException
 * @throws HttpMessageNotReadableException
 */
@SuppressWarnings("unchecked")
@Override
public Object read(Type type, Class<?> contextClass, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException {
    Object object = super.read(type, contextClass, inputMessage);
    String json = JSONObject.toJSONString(object);
    String jsonResult = null;
    if (json.startsWith("[")){
        JSONArray jsonArray = JSONArray.parseArray(json);
        if (jsonArray != null && !jsonArray.isEmpty()){
            List<Map<String, Object>> result = Lists.newArrayList();
            for (int i=0; i<jsonArray.size(); i++){
                Map<String, Object> map = (Map<String, Object>) jsonArray.get(i);
                Map<String, Object> removeSpaceMap = removeSpace(map);
                result.add(removeSpaceMap);
            }
         jsonResult = JSON.toJSONString(result);
        }
    }else {
        Map<String,Object> map = (Map<String, Object>) JSONObject.parse(json);

        Map<String, Object> removeSpaceMap = removeSpace(map);
        jsonResult = JSON.toJSONString(removeSpaceMap);
    }


    //注释掉Gson，转换默认将Integer，Long等转换成Double，内部处理看作Number
    /*Gson gson = new Gson();
    return gson.fromJson(removeSpaceJson, type);*/
    return JSONObject.parseObject(jsonResult, type);
}


private Map<String, Object> removeSpace(Map<String, Object> map){
  Set<Map.Entry<String, Object>> entrySet = map.entrySet();

  Map<String, Object> removeSpaceMap = Maps.newHashMap();
  for (Map.Entry<String, Object> entry : entrySet){
      if (entry.getValue() instanceof String){
          removeSpaceMap.put(entry.getKey(), ((String) entry.getValue()).trim());
      }else {
          removeSpaceMap.put(entry.getKey(),entry.getValue());
      }
  }
  return removeSpaceMap;
}