java处理json数据

目前JAVA支持处理JSON程序的第三方JAR包特别多, 可以在json官网进行下载;
地址: www.json.org
这里我们使用的是谷歌公司的gson-2.2.4.jar 进行解析;


实例如下:
List 集合 转换成 JSON格式
Gson gson = new Gson();
List<String> testList = new ArrayList<String>();
testList.add("first");
testList.add("second");
String listToJson = gson.toJson(testList);
System.out.println(listToJson); //prints ["first","second"]



Map 集合 转换成 JSON格式
Gson gson = new Gson();
Map<String,Object> testMap = new HashMap<String,Object>();
testMap.put("id", 1001);
testMap.put("name","中国");
String mapToJson = gson.toJson(testMap);
System.out.println(mapToJson); //prints {"id":1001,"name":"中国"}

带泛型的List 集合 转换成 json格式
List<ProCityBean> list = new ArrayList<ProCityBean>();
for (int i = 0; i < 2; i++) {
list.add(new ProCityBean(i * 100, "china" + i, i, Byte.valueOf(""+ i)));
}
Gson gson = new Gson();
String listToJson = gson.toJson(list);
System.out.println(listToJson); // [{"id":0,"name":"china0","parentId":0,"state":0},{"id":100,"name":"china1","parentId":1,"state":1}]
//类型转换一下
Type type = new TypeToken<List<ProCityBean>>(){}.getType();
String listToJson2 = gson.toJson(list, type);
System.out.println(listToJson2);


json字符串转换成List对象
String json = "['first','second']";
Gson gson = new Gson();
List<Object> list = gson.fromJson(json, ArrayList.class);
System.out.println(list); //prints [first, second]


json字符串转换成Bean对象
String json = "{'id':1001,'name':'china0','parentId':0,'state':0}";
Gson gson = new Gson();
ProCityBean bean = (ProCityBean)gson.fromJson(json, ProCityBean.class);
System.out.println(bean); //prints com.dom4j.ProCityBean@15dfd77


字符串JSON转换成List带泛型对象
String json = " [{'id':1001,'name':'china0','parentId':0,'state':0},{'id':100,'name':'china1','parentId':1,'state':1}]";
Gson gson = new Gson();
Type type = new TypeToken<List<ProCityBean>>(){}.getType();
List<ProCityBean> list = gson.fromJson(json, type);
System.out.println(list);//[com.dom4j.ProCityBean@1891d8f, com.dom4j.ProCityBean@f3d6a5]



bean日期转换
public static String getSon2(List<UserBean> list){
GsonBuilder builder = new GsonBuilder();
builder.setDateFormat("yyyy-MM-dd");
Gson gson = builder.create();

String s = gson.toJson(list);
return s;
}