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;

     }

 }