android转jsonobject
⑴ android 怎么看json数据格式
给服务端发送请求后,服务端会返回一连串的数据,这些数据在大部分情况下都是XML格式或者JSON格式。然后JSON相对XML来说解析相对方便一些,所以先说说JSON的解析。
JSON的基本数据格式有这几种:
1.一个JSON对象——JSONObject
{"name":"胡小威" , "age":20 , "male":true}
2.一个JSON数组——JSONArray
[{"name":"胡小威" , "age":20 , "male":true},{"name":"赵小亮" , "age":22 , "male":false}]
3.复杂一点的JSONObject
{"name":"胡小威", "age"=20, "male":true, "address":{"street":"岳麓山南", "city":"长沙","country":"中国"}}
4.复杂一点的JSONArray
[
{"name":"胡小威", "age"=20, "male":true, "address":{"street":"岳麓山南", "city":"长沙","country":"中国"}},
{"name":"赵小亮", "age"=22, "male":false, "address":{"street":"九州港", "city":"珠海","country":"中国"}}
]
5.来个更复杂的,这是我从爱帮公交上扒取的数据
{"buses":{"bus":[{"last_foot_dist":"0","time":"37","segments":{"segment":[{"line_name":"立珊专线(中南大学学生公寓-长沙火车站)","foot_dist":"362","stat_xys":"","stats":"岳麓山南;湖南师大;二里半;岳麓山北;市四医院;华图教育(太平街口);牛耳教育(南阳街口);韭菜园;曙光路口;长岛路口;长沙火车站","end_stat":"长沙火车站","line_xys":"","line_dist":"7535","start_stat":"岳麓山南"}]},"foot_dist":"362","dist":"7897"},{"last_foot_dist":"0","time":"41","segments":{"segment":[{"line_name":"旅1路(科教新村-长沙火车站)","foot_dist":"337","stat_xys":"","stats":"岳麓山南;湖南师大;二里半;岳麓山北;市四医院;华图教育(太平街口);蔡锷中路口;韭菜园;乔庄;曙光路口;长岛路口;五一东村;车站路口;长沙火车站","end_stat":"长沙火车站","line_xys":"","line_dist":"7822","start_stat":"岳麓山南"}]},"foot_dist":"337","dist":"8159"}]}}
接下来是解析部分
一、直接解析
1.{"name":"胡小威" , "age":20 , "male":true}
java代码
public void parseJsonObject(String json) {
try {
JSONObject jsonObject = new JSONObject(json);
String name = jsonObject.getString("name");
int age = jsonObject.getInt("age");
boolean male = jsonObject.getBoolean("male");
//接下来该干嘛干嘛
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
2.[{"name":"胡小威" , "age":20 , "male":true},{"name":"赵小亮" , "age":22 , "male":false}]
Java代码
public void parseJSONArray(String json) {
try {
JSONArray jsonArray = new JSONArray(json);
for (int i = 0; i < jsonArray.length(); i++) {
jsonObject = jsonArray.getJSONObject(i);
String name = jsonObject.getString("name");
int age = jsonObject.getInt("age");
boolean male = jsonObject.getBoolean("male");
//接下来该干嘛干嘛
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
3.{"name":"胡小威", "age"=20, "male":true, "address":{"street":"岳麓山南", "city":"长沙","country":"中国"}}
Java代码
public void parseJsonPerson(String json) {
try {
JSONObject jsonObject = new JSONObject(json);
String name = jsonObject.getString("name");
int age = jsonObject.getInt("age");
boolean male = jsonObject.getBoolean("male");
JSONObject addressJSON = jsonObject.getJSONObject("address");
String street = addressJSON.getString("street");
String city = addressJSON.getString("city");
String country = addressJSON.getString("country");
Address address = new Address(street, city, country);
Person person = new Person(name, age, male, address);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
4.
[
{"name":"胡小威", "age"=20, "male":true, "address":{"street":"岳麓山南", "city":"长沙","country":"中国"}},
{"name":"赵小亮", "age"=22, "male":false, "address":{"street":"九州港", "city":"珠海","country":"中国"}}
]
Java代码
public void parseJsonArrayPerson(String json) {
List<Person> persons = new ArrayList<Person>();
try {
jsonArray = new JSONArray(json);
for (int i = 0; i < jsonArray.length(); i++) {
jsonObject = jsonArray.getJSONObject(i);
String name = jsonObject.getString("name");
int age = jsonObject.getInt("age");
boolean male = jsonObject.getBoolean("male");
JSONObject addressJSON = jsonObject.getJSONObject("address");
String street = addressJSON.getString("street");
String city = addressJSON.getString("city");
String country = addressJSON.getString("country");
Address address = new Address(street, city, country);
Person person = new Person(name, age, male, address);
persons.add(person);
Log.v("juno", person.toString());
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Log.v("juno", persons.toString());
}
5. {"buses":{"bus":[{"last_foot_dist":"0","time":"37","segments":{"segment":[{"line_name":"立珊专线(中南大学学生公寓-长沙火车站)","foot_dist":"362","stat_xys":"","stats":"岳麓山南;湖南师大;二里半;岳麓山北;市四医院;华图教育(太平街口);牛耳教育(南阳街口);韭菜园;曙光路口;长岛路口;长沙火车站","end_stat":"长沙火车站","line_xys":"","line_dist":"7535","start_stat":"岳麓山南"}]},"foot_dist":"362","dist":"7897"},{"last_foot_dist":"0","time":"41","segments":{"segment":[{"line_name":"旅1路(科教新村-长沙火车站)","foot_dist":"337","stat_xys":"","stats":"岳麓山南;湖南师大;二里半;岳麓山北;市四医院;华图教育(太平街口);蔡锷中路口;韭菜园;乔庄;曙光路口;长岛路口;五一东村;车站路口;长沙火车站","end_stat":"长沙火车站","line_xys":"","line_dist":"7822","start_stat":"岳麓山南"}]},"foot_dist":"337","dist":"8159"}]}}
Java代码
public List<Salution> parseJSON(String str){
Log.d("返回的JSON数据:", str);
List<Salution> busList = new ArrayList<Salution>();
try {
JSONObject jsonObject = new JSONObject(str);
JSONObject busesJSON = jsonObject.getJSONObject("buses");
JSONArray busJSArray=busesJSON.getJSONArray("bus");
for(int i=0;i<busJSArray.length();i++){
JSONObject busJSObject = busJSArray.getJSONObject(i);
JSONObject segsJSObject=busJSObject.getJSONObject("segments");
JSONArray segJSArray=segsJSObject.getJSONArray("segment");
Salution st=new Salution();
for(int j=0;j<segJSArray.length();j++){
if(j==0){
JSONObject segJSObject = segJSArray.getJSONObject(j);
st.setLine_name1(segJSObject.getString("line_name"));
Log.d("line_name", segJSObject.getString("line_name"));
st.setStats1(segJSObject.getString("stats"));
st.setEnd_stat1(segJSObject.getString("end_stat"));
st.setStart_stat1(segJSObject.getString("start_stat"));
}
if(j==1){
JSONObject segJSObject = segJSArray.getJSONObject(j);
st.setLine_name2(segJSObject.getString("line_name"));
Log.d("line_name", segJSObject.getString("line_name"));
st.setStats2(segJSObject.getString("stats"));
st.setEnd_stat2(segJSObject.getString("end_stat"));
st.setStart_stat2(segJSObject.getString("start_stat"));
}
}
busList.add(st);
}
return busList;
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
这里我只是简单获取了几个我想要的数据。
二、使用JSON类库Gson 来解析JSON
Gson 是 Google 提供的用来在 Java 对象和 JSON 数据之间进行映射的 Java 类库。可以将一个 JSON 字符串转成一个 Java 对象,或者反过来。
首先,从 code.google.com/p/google-gson/downloads/list下载GsonAPI
Java代码
google-gson-1.7.1-release.zip
再把gson-1.7.jar 到libs
可以使用两种方法解析
①、通过获取JsonReader对象解析JSON数据:
Java代码
String jsonData = "[{\"username\":\"arthinking\",\"userId\":001},{\"username\":\"Jason\",\"userId\":002}]";
try{
JsonReader reader = new JsonReader(new StringReader(jsonData));
reader.beginArray();
while(reader.hasNext()){
reader.beginObject();
while(reader.hasNext()){
String tagName = reader.nextName();
if(tagName.equals("username")){
System.out.println(reader.nextString());
}
else if(tagName.equals("userId")){
System.out.println(reader.nextString());
}
}
reader.endObject();
}
reader.endArray();
}
catch(Exception e){
e.printStackTrace();
}
②、通过把JSON数据映射成一个对象,使用Gson对象的fromJson()方法获取一个对象数组进行操作
Java代码
Type listType = new TypeToken<LinkedList<User>>(){}.getType();
Gson gson = new Gson();
LinkedList<User> users = gson.fromJson(jsonData, listType);
for (Iterator iterator = users.iterator(); iterator.hasNext();) {
User user = (User) iterator.next();
System.out.println(user.getUsername());
System.out.println(user.getUserId());
}
我一般是采用直接解析,添加类库神马的最讨厌了···
还有,抱怨一下,iteye的编辑弱爆了!!!
转载
⑵ net.sf.json.JSONObject与Android自带的JSON解析类冲突怎么办
在Android中,由于类名相同,可能造成冲突,解决方案:
尽量使用同一个库下的JSON解析工具。
如果类型相同,但是包名不同,建议使用完整的包名+类名定义变量,例如java中,java.sql.Date和java.uitl.Date两个都是Date类,但是怎么区分呢,就可以通过包名+类名来区分:
java.sql.Date date1 = new java.sql.Date();
java uitl.Date date2 = new java.uitl.Date();
JSONObject也一样,可以使用这种方式。
Android中,json的解析,建议使用google提供的Gson这个开源库,json的解析或者对象与json转换,只需要一行代码。
Gson gson = new Gson();
gson.toJson(object); gson.fromJson(json.Object.class);
⑶ android 使用JSONObject 数组报错, NullPointerException
错误是指MainActivity的第85行,你看下你代码,如果解析出来的一个类为空,这个类在使用的时候就会报空指针,你加个非空判断。
另外,你用的是eclipse么,如果是Android studio的话,你引入个gson或者fastjson依赖,一句话就解析完成了;还有个插件,GsonFormat,直接把JSON完整的粘贴到里面,自动生成实体类