引用Maven库：

            
                
     
      com.fasterxml.jackson.core
                 
     
      jackson-core
                 
     
      2.4.3
             
            
                
     
      com.fasterxml.jackson.core
                 
     
      jackson-databind
                 
     
      2.4.3
             
    

public class JacksonUtil {    private static final Logger logger = LoggerFactory.getLogger(JacksonUtil.class);    private static final ObjectMapper objectMapper = new ObjectMapper();    static {        /**         * 默认非空不输出，时间格式         */        objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);        objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));    }    /**     * 将 Java 对象转为 JSON 字符串     */    public static 
    
      String toJSON(T obj) {        String jsonStr;        try {            jsonStr = objectMapper.writeValueAsString(obj);        } catch (Exception e) {            logger.error("Java 转 JSON 出错！", e);            throw new RuntimeException(e);        }        return jsonStr;    }    /**     * 将 JSON 字符串转为 Java 对象     */    public static 
     
       T fromJSON(String json, Class
      
        type) {        T obj;        try {            obj = objectMapper.readValue(json, type);        } catch (Exception e) {            logger.error("JSON 转 Java 出错！", e);            throw new RuntimeException(e);        }        return obj;    }}