Gson简单使用

1.简单的处理list和map

Java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"}??
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
List<TestBean> testBeanList = new ArrayList<TestBean>();???
TestBean testBean = new TestBean();???
testBean.setId("id");???
testBean.setName("name");???
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
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>]]??
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
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());???
??? }???
}??
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
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());??????
??? }??????
??
}??
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
/**??
???? * 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);???
??? }??
/**
* 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
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]]??
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>