jackson 实现对象转换为JSON 、JSON转换为对象和JSON 转换为List。以及fastjson转换

小咪咪 2022-05-21 10:17 296阅读 0赞

package com.xxx.common.utils;
    
    
    import java.io.IOException;
    import java.util.ArrayList;
    import java.util.List;
    
    import com.alibaba.fastjson.JSON;
    import com.alibaba.fastjson.serializer.SerializerFeature;
    import com.fasterxml.jackson.core.JsonGenerationException;
    import com.fasterxml.jackson.core.JsonGenerator;
    import com.fasterxml.jackson.core.JsonProcessingException;
    import com.fasterxml.jackson.databind.JavaType;
    import com.fasterxml.jackson.databind.JsonMappingException;
    import com.fasterxml.jackson.databind.JsonSerializer;
    import com.fasterxml.jackson.databind.ObjectMapper;
    import com.fasterxml.jackson.databind.SerializerProvider;
    
    /** * 项目名称：ppsp_eonline * 类名称：JsonUtils * 类描述：用于转换输出对象 * @version */ public class JsonUtils {
       
       protected static final org.slf4j.Logger logger = org.slf4j.LoggerFactory
               .getLogger(JsonUtils.class);
       
    // private static Logger logger=Logger.getLogger(JsonUtils.class); private static ObjectMapper objectMapper = new ObjectMapper();
     
       private JsonUtils() {}
       
       static{
          /**重写objectMapper 将null转换为"" **/ objectMapper.getSerializerProvider().setNullValueSerializer(
              new JsonSerializer<Object>() {
                 @Override
                  public void serialize(Object value, JsonGenerator jsonGenerator,SerializerProvider serializerProvider) throws IOException,JsonProcessingException {
                    jsonGenerator.writeString("");
                  }
              }
          );
       }
       
       /** * 方法名称: Object2JSON * 方法描述: 将对象转换为JSON * 返回类型: T * @throws */ @SuppressWarnings("unchecked")
       public static <T extends Object> T Object2JSON(Object object) {
          String jsonStr = null;
          try {
             jsonStr = objectMapper.writeValueAsString(object);
          } catch (JsonGenerationException e) {
             logger.error("JsonUtils Object2JSON JsonGenerationException",e);
          } catch (JsonMappingException e) {
             logger.error("JsonUtils Object2JSON JsonMappingException",e);
          } catch (IOException e) {
             logger.error("JsonUtils Object2JSON IOException",e);
          }
          return jsonStr == null ? null : (T) jsonStr;
       }
    
       /** * 方法名称: JSON2Object * 方法描述: 将JSON转换为对象 * 返回类型: T * @throws */ @SuppressWarnings("unchecked")
       public static <T extends Object> T JSON2Object(String JSONStr, Class<T> claz) {
          Object object = null;
          try {
             object = objectMapper.readValue(JSONStr, claz);
          } catch (JsonGenerationException e) {
             logger.error("JsonUtils JSON2Object JsonGenerationException",e);
          } catch (JsonMappingException e) {
             logger.error("JsonUtils JSON2Object JsonMappingException",e);
          } catch (IOException e) {
             logger.error("JsonUtils JSON2Object IOException",e);
          }
          return object != null ? (T) object : null;
       }
       
       /** * 方法名称: JSON2List * 方法描述: JSON 转换为List: * 返回类型: List<T> * @throws */ @SuppressWarnings("deprecation")
       public static <T> List<T> JSON2List(String jsonStr, Class<T> claz) {  
            List<T> result = null;  
            try{
               JavaType t = objectMapper.getTypeFactory().
                     constructParametricType(List.class, claz);  
               result = objectMapper.readValue(jsonStr, t);
            } catch (JsonGenerationException e) {
             logger.error("JsonUtils JSON2List JsonGenerationException",e);
          } catch (JsonMappingException e) {
             logger.error("JsonUtils JSON2List JsonMappingException",e);
          } catch (IOException e) {
             logger.error("JsonUtils JSON2List IOException",e);
          }
          return result==null?new ArrayList<T>():result;  
         }  
    
       
        /** * 方法名称: toJSONString * 方法描述: 将对象转换为String * 返回类型: String * @throws */ public static final String toJSONString(Object object){
          return JSON.toJSONString(object,SerializerFeature.WriteNonStringValueAsString);
       }
       
       /** * 方法名称: toJSON * 方法描述: 将java对象转换为JSON * 返回类型: Object * @throws */ public static final Object toJSON(Object javaObject){
          return JSON.toJSON(javaObject);
       }
       
       
        /** * 方法名称: parseObject * 方法描述: 将String转为对象<T> * 返回类型: T * @throws */ public static final <T> T parseObject(String jsonStr, Class<T> clazz){
          return JSON.parseObject(jsonStr,clazz);
       }
       
       /** * 方法名称: parseArray * 方法描述: 将String转换List<T>: * 返回类型: List<T> * @throws */ public static final <T> List<T> parseArray(String jsonStr, Class<T> clazz){
          return JSON.parseArray(jsonStr, clazz);
       }
    }

其他的fastjosn转换请参考：

https://blog.csdn.net/xuforeverlove/article/details/80842148