google gson学习

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



1.简单的处理list和map
Java代码  收藏代码

    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  收藏代码

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

Java代码  收藏代码

    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  收藏代码

    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> { 
     
        @Override 
        public java.util.Date deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) 
                throws JsonParseException { 
            return new java.util.Date(json.getAsJsonPrimitive().getAsLong()); 
        } 
    } 


Java代码  收藏代码

    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  收藏代码

    /**
         * 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  收藏代码

    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