jsonUtil 工具类

 package org.konghao.basic.util;

 import java.io.IOException;
 import java.io.StringWriter;

 import com.fasterxml.jackson.core.JsonFactory;
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.core.JsonParseException;
 import com.fasterxml.jackson.databind.JsonMappingException;
 import com.fasterxml.jackson.databind.ObjectMapper;

 public class JsonUtil {
     private static JsonUtil ju;
     private static JsonFactory jf;
     private static ObjectMapper mapper;

     private JsonUtil() {
     }

     public static JsonUtil getInstance() {
         if (ju == null)
             ju = new JsonUtil();
         return ju;
     }

     public static ObjectMapper getMapper() {
         if (mapper == null) {
             mapper = new ObjectMapper();
         }
         return mapper;
     }

     public static JsonFactory getFactory() {
         if (jf == null)
             jf = new JsonFactory();
         return jf;
     }

     public String obj2json(Object obj) {
         JsonGenerator jg = null;
         try {
             jf = getFactory();
             mapper = getMapper();
             StringWriter out = new StringWriter();
             jg = jf.createJsonGenerator(out);
             mapper.writeValue(jg, obj);
             return out.toString();
         } catch (IOException e) {
             e.printStackTrace();
         } finally {
             try {
                 if (jg != null)
                     jg.close();
             } catch (IOException e) {
                 e.printStackTrace();
             }
         }
         return null;
     }

     public Object json2obj(String json, Class<?> clz) {
         try {
             mapper = getMapper();
             return mapper.readValue(json, clz);
         } catch (JsonParseException e) {
             e.printStackTrace();
         } catch (JsonMappingException e) {
             e.printStackTrace();
         } catch (IOException e) {
             e.printStackTrace();
         }
         return null;
     }

 }