Google Gson

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

1.简单的处理list和map

Java代码

1. Gson gson = new Gson();  
2. List testList = new ArrayList();  
3. testList.add("first");  
4. testList.add("second");  
5. String listToJson = gson.toJson(testList);  
6. System.out.println(listToJson);       
7. //prints ["first","second"]  
8.   
9. Map testMap = new HashMap();  
10. testMap.put("id", "id.first");  
11. testMap.put("name","name.second");  
12. String mapToJson = gson.toJson(testMap);  
13. System.out.println(mapToJson);    
14. //prints {"id":"id.first","name":"name.second"}  

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

Java代码

1. List<TestBean> testBeanList = new ArrayList<TestBean>();  
2. TestBean testBean = new TestBean();  
3. testBean.setId("id");  
4. testBean.setName("name");  
5. testBeanList.add(testBean);  

List<TestBean> testBeanList = new ArrayList<TestBean>();TestBean testBean = new TestBean();testBean.setId("id");testBean.setName("name");testBeanList.add(testBean);

Java代码

1. java.lang.reflect.Type type = new com.google.gson.reflect.TypeToken<List<TestBean>>() {  
2. }.getType();  
3. String beanListToJson = gson.toJson(testBeanList,type);  
4. System.out.println(beanListToJson);  
5. //prints [{"id":"id","name":"name"}]  
6.   
7. List<TestBean> testBeanListFromJson = gson.fromJson(beanListToJson, type);  
8. System.out.println(testBeanListFromJson);  
9. //prints [TestBean@1ea5671[id=id,name=name,birthday=<null>]]  

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

Java代码

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

import java.lang.reflect.Type;import com.google.gson.JsonDeserializationContext;import com.google.gson.JsonDeserializer;import com.google.gson.JsonElement;import com.google.gson.JsonParseException;public class UtilDateDeserializer implements JsonDeserializer<java.util.Date> {@Overridepublic java.util.Date deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)throws JsonParseException {return new java.util.Date(json.getAsJsonPrimitive().getAsLong());}}

Java代码

1. import java.lang.reflect.Type;  
2.   
3. import com.google.gson.JsonElement;  
4. import com.google.gson.JsonPrimitive;  
5. import com.google.gson.JsonSerializationContext;  
6. import com.google.gson.JsonSerializer;  
7.   
8. public class UtilDateSerializer implements JsonSerializer<java.util.Date> {  
9.   
10.     @Override  
11.     public JsonElement serialize(java.util.Date src, Type typeOfSrc,     
12.             JsonSerializationContext context) {     
13.         return new JsonPrimitive(src.getTime());     
14.     }     
15.   
16. }  

import java.lang.reflect.Type;import com.google.gson.JsonElement;import com.google.gson.JsonPrimitive;import com.google.gson.JsonSerializationContext;import com.google.gson.JsonSerializer;public class UtilDateSerializer implements JsonSerializer<java.util.Date> {@Override    public JsonElement serialize(java.util.Date src, Type typeOfSrc,               JsonSerializationContext context) {           return new JsonPrimitive(src.getTime());       }   }

Java代码

1. /** 
2.      * 序列化方法 
3.      * @param bean 
4.      * @param type 
5.      * @return 
6.      */  
7.     public static String bean2json(Object bean, Type type) {  
8.         Gson gson = new GsonBuilder().registerTypeAdapter(java.util.Date.class, new UtilDateSerializer())  
9.                 .setDateFormat(DateFormat.LONG).create();  
10.         return gson.toJson(bean);  
11.     }  
12.   
13.     /** 
14.      * 反序列化方法 
15.      * @param json 
16.      * @param type 
17.      * @return 
18.      */  
19.     public static <T> T json2bean(String json, Type type) {  
20.         Gson gson = new GsonBuilder().registerTypeAdapter(java.util.Date.class, new UtilDateDeserializer())  
21.                 .setDateFormat(DateFormat.LONG).create();  
22.         return gson.fromJson(json, type);  
23.     }  

/** * 序列化方法 * @param bean * @param type * @return */public static String bean2json(Object bean, Type type) {Gson gson = new GsonBuilder().registerTypeAdapter(java.util.Date.class, new UtilDateSerializer()).setDateFormat(DateFormat.LONG).create();return gson.toJson(bean);}/** * 反序列化方法 * @param json * @param type * @return */public static <T> T json2bean(String json, Type type) {Gson gson = new GsonBuilder().registerTypeAdapter(java.util.Date.class, new UtilDateDeserializer()).setDateFormat(DateFormat.LONG).create();return gson.fromJson(json, type);}

现在开始测试

Java代码

1. 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]]  

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

后记：对于java.sql.Date的转化同上类似，写两个类用于其序列化和反序列化即可SQLDateDeserializer implements JsonDeserializer<java.sql.Date>

SQLDateSerializer implements JsonSerializer<java.sql.Date>

 对于GsonBuilder详见:

 http://google-gson.googlecode.com/svn/tags/1.2.3/docs/javadocs/com/google/gson/GsonBuilder.html

*注:TestBean就是一个带id、name、birthday的javabean，就不在这里贴代码了