Two ways to parse JSON data using Gson in Android

JSON is an XML-like common data Interchange Format, which has higher transfer efficiency than XML; This article will introduce two methods to parse JSON data, the need for friends can refer to JSON is a common XML-like data Interchange format, with higher efficiency than XML.
Structurally, all data can eventually be decomposed into three types:
The first type is scalar (scalar), which is a single string (string) or number (numbers), such as "Beijing", a separate word.
The second type is the sequence (sequence), which is a number of related data that are tied together in a certain order, also called an array or list, such as "Beijing, Shanghai."
The third type is mapping (mapping), a name/value pair (Name/value), which has a name and a value corresponding to it, also known as hash (hash) or dictionary (dictionary), such as "Capital: Beijing".
JSON specifications are very simple, with only one page hundreds of words can be said clearly, and Douglas Crockford claims that this specification never need to upgrade, because the provisions of the provision.
1) The data is separated by commas (",").
2) The map is represented by a colon (":").
3) a set (array) of side data is expressed in square brackets ("[]").
4) The Set of Mappings (objects) are represented by curly braces ("{}").

Use Gson to parse JSON data in Android
First, download Gsonapi from Code.google.com/p/google-gson/downloads/list:
Google-gson-1.7.1-release.zip
Copy the Gson-1.7.jar to Libs (the project root directory creates a new Libs folder).
You can use the following two methods to parse JSON data:
Parse the JSON data by getting the Jsonreader object: The code looks like this:

1String Jsondata ="[{\ "username\": \ "arthinking\", \ "userid\": 001},{\ "username\": \ "jason\", \ "userid\": 002}]"; 2 Try{ 3Jsonreader reader =NewJsonreader (NewStringReader (jsondata)); 4 Reader.beginarray ();5  while(Reader.hasnext ()) {6 Reader.beginobject ();7  while(Reader.hasnext ()) {8String TagName =reader.nextname ();9 if(Tagname.equals ("username")){ TenSystem. out. println (Reader.nextstring ()); One }  A Else if(Tagname.equals ("userId")){  -System. out. println (Reader.nextstring ()); - }  the }  - Reader.endobject (); - }  - Reader.endarray (); + }  - Catch(Exception e) { + e.printstacktrace (); A}

By mapping the JSON data to an object, use the Fromjson () method of the Gson object to get an array of objects to manipulate:
Create a Pojo object corresponding to the JSON data User.java:

The code is as follows:

1  Public classUser {2 PrivateString username;3 Private intuserId;4  PublicString GetUserName () {5 returnusername;6 } 7  Public voidSetusername (String username) {8  This. Username =username;9 } Ten  Public intgetUserId () { One returnuserId; A }  -  Public voidSetuserid (intuserId) {  -  This. UserId =userId; the }  -}

Use the Gson object to get the user object data for the appropriate operation:

The code is as follows:

1 " {\ "username\": \ "arthinking\", \ "userid\": 001} "  2new3 User user = Gson.fromjson (jsondata, user.  Class4 System.  out  5 System.  out

Two ways to parse JSON data using Gson in Android