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

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