google gson使用

关键字: json gson java

Gson网址http://code.google.com/p/google-gson/

1.简单的处理list和map

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Gson gson = new Gson(); List testList = new ArrayList(); testList.add("first"); testList.add("second"); String listToJson = gson.toJson(testList); System.out.println(listToJson);      //prints ["first","second"]    Map testMap = new HashMap(); testMap.put("id", "id.first"); testMap.put("name","name.second"); String mapToJson = gson.toJson(testMap); System.out.println(mapToJson);   //prints {"id":"id.first","name":"name.second"}

 2.处理带泛型的集合

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List<TestBean> testBeanList = new ArrayList<TestBean>(); TestBean testBean = new TestBean(); testBean.setId("id"); testBean.setName("name"); testBeanList.add(testBean);            java.lang.reflect.Type type = new com.google.gson.reflect.TypeToken<List<TestBean>>() { }.getType(); String beanListToJson = gson.toJson(testBeanList,type); System.out.println(beanListToJson); //prints [{"id":"id","name":"name"}]            List<TestBean> testBeanListFromJson = gson.fromJson(beanListToJson, type); System.out.println(testBeanListFromJson); //prints [TestBean@1ea5671[id=id,name=name,birthday=<null>]]

map等其他集合类型同上

3.Date类型转化

先写工具类

1. import java.lang.reflect.Type; 
2 2. 
3 3. import com.google.gson.JsonDeserializationContext; 
4 4. import com.google.gson.JsonDeserializer; 
5 5. import com.google.gson.JsonElement; 
6 6. import com.google.gson.JsonParseException; 
7 7. 
8 8. publicclass UtilDateDeserializer implements JsonDeserializer<java.util.Date> { 
9 9. 
10 10. @Override 
11 11. public java.util.Date deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) 
12 12. throws JsonParseException { 
13 13. returnnew java.util.Date(json.getAsJsonPrimitive().getAsLong()); 
14 14. } 
15 15. } 

1. import java.lang.reflect.Type; 
22. 
33. import com.google.gson.JsonElement; 
44. import com.google.gson.JsonPrimitive; 
55. import com.google.gson.JsonSerializationContext; 
66. import com.google.gson.JsonSerializer; 
77. 
88. publicclass UtilDateSerializer implements JsonSerializer<java.util.Date> { 
99. 
1010. @Override 
1111. public JsonElement serialize(java.util.Date src, Type typeOfSrc, 
1212. JsonSerializationContext context) { 
1313. returnnew JsonPrimitive(src.getTime()); 
1414. } 
1515. 
1616. } 

1. /** 
2 2. * 序列化方法 
3 3. * @param bean 
4 4. * @param type 
5 5. * @return 
6 6. */ 
77. publicstatic String bean2json(Object bean, Type type) { 
88. Gson gson =new GsonBuilder().registerTypeAdapter(java.util.Date.class, new UtilDateSerializer()) 
99. .setDateFormat(DateFormat.LONG).create(); 
1010. return gson.toJson(bean); 
1111. } 
1212. 
1313. /** 
14 14. * 反序列化方法 
15 15. * @param json 
16 16. * @param type 
17 17. * @return 
18 18. */ 
1919. publicstatic<T> T json2bean(String json, Type type) { 
2020. Gson gson =new GsonBuilder().registerTypeAdapter(java.util.Date.class, new UtilDateDeserializer()) 
2121. .setDateFormat(DateFormat.LONG).create(); 
2222. return gson.fromJson(json, type); 
2323. } 

# List<TestBean> testBeanList =new ArrayList<TestBean>(); 
2# TestBean testBean =new TestBean(); 
3# testBean.setId("id"); 
4# testBean.setName("name"); 
5# testBean.setBirthday(new java.util.Date()); 
6# testBeanList.add(testBean); 
7# 
8# java.lang.reflect.Type type =new com.google.gson.reflect.TypeToken<List<TestBean>>() { 
9# }.getType(); 
10# String beanListToJson = bean2json(testBeanList, type); 
11# System.out.println("beanListToJson:"+ beanListToJson); 
12# //prints [{"id":"id","name":"name","birthday":1256531559390}] 
13# 
14# List<TestBean> testBeanListFromJson = json2bean(beanListToJson, type); 
15# System.out.println(testBeanListFromJson); 
16# //prints [TestBean@77a7f9[id=id,name=name,birthday=Mon Oct 26 12:39:05 CST 2009]]