示例
- import java.util.ArrayList;
- import java.util.List;
- import java.util.HashMap;
- import java.util.Map;
-
- import com.alibaba.fastjson.JSON;
- import com.alibaba.fastjson.JSONArray;
- import com.alibaba.fastjson.JSONObject;
-
- class User {
- private int id;
- private String name;
- public int getId() {
- return id;
- }
- public void setId(int id) {
- this.id = id;
- }
- public String getName() {
- return name;
- }
- public void setName(String name) {
- this.name = name;
- }
- }
-
- class Group {
- private int id;
- private String name;
- private List < User > list = new ArrayList < User > ();
- public int getId() {
- return id;
- }
- public void setId(int id) {
- this.id = id;
- }
- public String getName() {
- return name;
- }
- public void setName(String name) {
- this.name = name;
- }
- public List < User > getList() {
- return list;
- }
- public void setList(List < User > list) {
- this.list = list;
- }
- }
-
- class Weibo {
- private String id;
- private String city;
-
- public Weibo(String id, String city) {
- this.id = id;
- this.city = city;
- }
-
- public Weibo() {}
-
- public String getId() {
- return id;
- }
-
- public void setId(String id) {
- this.id = id;
- }
-
- public String getCity() {
- return city;
- }
-
- public void setCity(String city) {
- this.city = city;
- }
- }
-
- public class JsonDemo {
- public static void main(String[] args) {
- json2JsonObjectM1(); //将Json文本数据信息转换为JsonObject对象,然后利用键值对的方式获取信息
- json2BeanM2(); //将Json文本数据转换为JavaBean数据!
- json2JSONArrayM3(); //将json数据转化为JSONArray:
- json2JavaBeanM4(); //将JSON文本转换为JavaBean的集合;转换为单纯的1个Object:parseObject(String text, Class<T> clazz);
- bean2JsonM5(); //将JavaBean转换为Json格式的数据/Json文本 用户数据的传递:例如上传服务器
- bean2JSONObjectM6(); //将JavaBean转换为JSON对象
- complexExampleM7(); //一个相对复杂的例子:
- complex2JsonM8(); //一个复杂的Object到Json的Demo
- complexMap2JsonM9(); //将Map数据转换为JsonString的Demo;这个对RedBoy服务端不就直接破了嘛!
- }
-
- /**
- * 将Json文本数据信息转换为JsonObject对象,然后利用键值对的方式获取信息
- */
- private static void json2JsonObjectM1() {
- //一个JsonObject文本数据
- String s = "{\"name\":\"liuzhao\"}";
- //将JsonObject数据转换为Json
- JSONObject object = JSON.parseObject(s);
- //利用键值对的方式获取到值
- System.out.println(object.get("name"));
- /**
- * 打印:
- * liuzhao
- */
- }
-
- /**
- * 将Json文本数据转换为JavaBean数据!
- * 需要注意的是:这时候的Json文本信息中的键的名称必须和JavaBean中的字段名称一样!键中没有的在这个JavaBean中就显示为null!
- */
- private static void json2BeanM2() {
- String s = "{\"id\":\"0375\",\"city\":\"平顶山\"}";
- //一个简单方便 的方法将Json文本信息转换为JsonObject对象的同时转换为JavaBean对象!
- Weibo weibo = JSON.parseObject(s, Weibo.class); //Weibo类在下边定义
- System.out.println(weibo.getId());
- System.out.println(weibo.getCity());
- //打印的结果 0375
- // 平顶山
- }
-
- /**
- * 将Map类型的数据转换为JsonString
- */
- private static void complexMap2JsonM9() {
- Group group = new Group();
- group.setId(1);
- group.setName("group");
-
- User user1 = new User();
- user1.setId(2);
- user1.setName("user1");
-
- User user2 = new User();
- user2.setId(3);
- user2.setName("user2");
- group.getList().add(user1);
- group.getList().add(user2);
-
- Map < Integer,
- Object > map = new HashMap < Integer,
- Object > ();
- map.put(1, "No.1");
- map.put(2, "No.2");
- map.put(3, group.getList());
-
- String jsonString = JSON.toJSONString(map);
- System.out.println(jsonString);
- /**
- * 输出:{1:"No.1",2:"No.2",3:[{"id":2,"name":"user1"},{"id":3,"name":"user2"}]}
- */
- }
-
- /**
- * 由一个复杂的Object到Json的Demo
- */
- private static void complex2JsonM8() {
- Group group = new Group();
- group.setId(1);
- group.setName("group");
-
- User user1 = new User();
- user1.setId(2);
- user1.setName("user1");
-
- User user2 = new User();
- user2.setId(3);
- user2.setName("user2");
- group.getList().add(user1);
- group.getList().add(user2);
- String jsonString = JSON.toJSONString(group);
- System.out.println(jsonString);
- /**
- * 输出:{"id":1,"list":[{"id":2,"name":"user1"},{"id":3,"name":"user2"}],"name":"group"}
- */
- }
-
- /**
- * 一个相对复杂的例子:
- * JSON文本数据:
- * 首先是JSONObject,转换为JSONArray;
- * 然后将JSONArray转换为JavaBean
- */
- private static void complexExampleM7() {
- String s = "{js:[{id:\"110000\",\"city\":\"北#001京市\"},{id:\"110000\",\"city\":\"北#002京市\"}" + ",{id:\"110000\",\"city\":\"北#002京市\"},{id:\"110000\",\"city\":\"北#002京市\"}," + "{id:\"110000\",\"city\":\"#006北#005京市\"}," + "{id:\"110000\",\"city\":\"北#002京市\"}," + "{id:\"110000\",\"city\":\"北#002京市\"},{id:\"120000\",\"city\":\"天#009津市\"}]}";
-
- JSONObject object = JSON.parseObject(s);
- Object jsonArray = object.get("js");
- System.out.println(jsonArray);
- List < Weibo > list = JSON.parseArray(jsonArray + "", Weibo.class);
- for (Weibo weibo: list) {
- System.out.println(weibo.getCity());
- }
- }
-
- /**
- * 将JavaBean转换为JSON对象
- */
- private static void bean2JSONObjectM6() {
- Weibo weibo = new Weibo("0373", "洛阳");
- JSONObject json = (JSONObject) JSON.toJSON(weibo);
- System.out.println(json.get("id"));
- /**
- * 打印:
- * 0373
- */
- }
-
- /**
- * 将JSON文本转换为JavaBean的集合;
- * 内部实现肯定是:首先转换为JSONArray,然后再转换为List集合
- */
- private static void json2JavaBeanM4() {
- String s = "[{\"id\":\"0375\",\"city\":\"平顶山\"},{\"id\":\"0377\",\"city\":\"南阳\"}]";
- List < Weibo > list = JSON.parseArray(s, Weibo.class);
- for (Weibo weibo: list) {
- System.out.println(weibo.getCity());
- }
- /**
- * 打印:
- * 平顶山
- * 南阳
- */
- }
-
- /**
- * 将json数据转化为JSONArray:
- * 注意:获取到JSONArray之后(我们这里只是获取到JSONArray而不是JavaBean的List集合)
- * 获取JSONArray中的数据转换为String类型需要在外边加"";
- */
- private static void json2JSONArrayM3() {
- String s = "[{\"id\":\"0375\",\"city\":\"平顶山\"},{\"id\":\"0377\",\"city\":\"南阳\"}]";
- //将JSON文本转换为JSONArray
- JSONArray array = JSON.parseArray(s);
- //这行必须写:必须加上+"";不然会报出类型强转异常!
- String str = array.get(1) + "";
- System.out.println(array.get(0));
- JSONObject object = JSON.parseObject(str);
- System.out.println(object.get("id"));
- /**
- * {"city":"平顶山","id":"0375"}
- 0377
- */
- }
-
- /**
- * 将JavaBean转换为Json格式的数据/Json文本
- * 用户数据的传递:例如上传服务器
- */
- private static void bean2JsonM5() {
- Weibo weibo = new Weibo("123456", "上海");
- String string = JSON.toJSONString(weibo);
- System.out.println(string);
- /**
- * 打印:
- * {"city":"上海","id":"123456"}
- */
- }
-
- }
参考
http://www.oschina.net/code/snippet_228315_35122