jsonUtil 工具类

 1 package org.konghao.basic.util;
 2 
 3 import java.io.IOException;
 4 import java.io.StringWriter;
 5 
 6 import com.fasterxml.jackson.core.JsonFactory;
 7 import com.fasterxml.jackson.core.JsonGenerator;
 8 import com.fasterxml.jackson.core.JsonParseException;
 9 import com.fasterxml.jackson.databind.JsonMappingException;
10 import com.fasterxml.jackson.databind.ObjectMapper;
11 
12 public class JsonUtil {
13     private static JsonUtil ju;
14     private static JsonFactory jf;
15     private static ObjectMapper mapper;
16 
17     private JsonUtil() {
18     }
19 
20     public static JsonUtil getInstance() {
21         if (ju == null)
22             ju = new JsonUtil();
23         return ju;
24     }
25 
26     public static ObjectMapper getMapper() {
27         if (mapper == null) {
28             mapper = new ObjectMapper();
29         }
30         return mapper;
31     }
32 
33     public static JsonFactory getFactory() {
34         if (jf == null)
35             jf = new JsonFactory();
36         return jf;
37     }
38 
39     public String obj2json(Object obj) {
40         JsonGenerator jg = null;
41         try {
42             jf = getFactory();
43             mapper = getMapper();
44             StringWriter out = new StringWriter();
45             jg = jf.createJsonGenerator(out);
46             mapper.writeValue(jg, obj);
47             return out.toString();
48         } catch (IOException e) {
49             e.printStackTrace();
50         } finally {
51             try {
52                 if (jg != null)
53                     jg.close();
54             } catch (IOException e) {
55                 e.printStackTrace();
56             }
57         }
58         return null;
59     }
60 
61     public Object json2obj(String json, Class<?> clz) {
62         try {
63             mapper = getMapper();
64             return mapper.readValue(json, clz);
65         } catch (JsonParseException e) {
66             e.printStackTrace();
67         } catch (JsonMappingException e) {
68             e.printStackTrace();
69         } catch (IOException e) {
70             e.printStackTrace();
71         }
72         return null;
73     }
74 
75 
76 }