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>

转载于：http://qsh123.iteye.com/blog/1181447