Android parsing JSON data

1.JSON (JavaScript Object Notation) is a lightweight data interchange format. It is based on a subset of JavaScript (standard ECMA-262 3rd edition-december 1999). JSON takes a completely language-independent text format, but also uses a similar idiom to the C language family (c, C + +, C #, Java, JavaScript, Perl, Python, etc.). These features make JSON an ideal data exchange language. Easy to read and write, but also easy to machine parse and generate (network transfer speed).

Data format for 2.json

1>object

{

"Name" AAAAAAAAA: "Jackson",

"Age": 100

 }

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M02/6C/47/wKioL1VEfuvCrs63AACLVIGXepU096.jpg "title=" Qq20150502153151.png "alt=" Wkiol1vefuvcrs63aaclvigxepu096.jpg "/>

2> Array

{

"Students":

[

{"Name": "Jackson", "Age": 100},

{"Name": "Yu", "Age": 22}

]

}

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M01/6C/47/wKioL1VEf5fRyhhAAAB_US2ItPE665.jpg "title=" Qq20150502153448.png "alt=" Wkiol1vef5fryhhaaab_us2itpe665.jpg "/>

Example: The server-side data generated by the return of JSON data format, the Android client to obtain JSON data, parse the JSON format of data.

1. Using JSON requires a few packages, download the next package placed in the server project engineering

Json-lib-2.3-jdk15.jar Commons-beanutils-1.7.0.jar Commons-httpclient-3.1.jar Commons-lang-2.3.jar Commons-logging-1.0.4.jar Commons-collections-3.1.jar ezmorph-1.0.3.jar2. Create a new project under MyEclipse, first create a new JSON tool class, and by invoking the tool class, you can convert the data into a JSON-formatted

public class Jsontools {public Jsontools () {//TODO auto-generated Constructor stub}/** * @param key * denotes JSON characters String header information * @param object * is the type of the parsed collection * @return */public static string createjsonstring (string key, Object value) {Jsonobject jsonobject = new Jsonobject (); Jsonobject.put (key, value); return jsonobject.tostring ();}

3. Assigning values to Objects

package com.json.service;import java.util.arraylist;import java.util.hashmap;import  Java.util.list;import java.util.map;import com.json.domain.person;public class jsonservice  {public jsonservice ()  {}    /*     * {" Person ": {" Address ":" Beijing "," id ": 1001," name ":" Jack "}}      */public person  getperson ()  {person person = new person (1001,  "Yu",  "Beijing"); return  person;}     /*     * {"Persons": [{"Address": "Guangxi", "id": 1001, " Name ":" Jack "},{" Address ":" Guangdong "," id ": 1002," name ":" Rose "}]}      */public  list<person> getlistperson ()  {List<Person> list = new  Arraylist<person> (); Person person1 = new person (1001,  "Yu",  "Guangxi"); person person2  = new person (1002,  "Rose",  "Guangdong"); List.add (Person1); List.add (Person2);return  List;}    /*    * {"liststring": ["Beijing", "Shanghai", "Hunan"]}      */public list<string> getliststring ()  {list<string> list  = new ArrayList<String> (); List.add ("Beijing"); List.add ("Shanghai"); List.add ("Hunan"); Return list;}     //{"Listmap": [{"id": 1001, "Address": "Beijing", "name": "Jack"},{"id": 1002, "Address": " Shanghai "," name ":" Rose "}]} public list<map<string, object>> getlistmaps ()  {list<map<string, object>> list = new arraylist<map<string,  Object>> (); Map<string, object> map1 = new hashmap<string, object> (); Map1.put (" ID ",  1001); Map1.put (" Name ", " Jack ") Map1.put (" Address ", " Beijing "); Map<string, object> map2 = new hashmap<string, object> (); Map2.put ("id",  1002 ); Map2.put ("name",  "Rose"), Map2.put ("Address",  "Shanghai"); List.add (MAP1); List.add (MAP2); return  list;}}

4. Create a new servlet call method that generates JSON, and then output the generated JSON-formatted data to the client

Public void dopost (Httpservletrequest request, httpservletresponse response) throws  servletexception, ioexception {response.setcontenttype ("Text/html;charset=utf-8"); Request.setcharacterencoding ("Utf-8"); Response.setcharacterencoding ("Utf-8"); Printwriter out = response.getwriter (); string jsonstring =  ""; String action_flag =request.getparameter ("Action_flag");if  (action_flag.equals ("person"))   {jsonstring = jsontools.createjsonstring ("person",  service.getperson ()); System.out.println ("person");}  else if  (Action_flag.equals ("persons")  {jsonString =  Jsontools.createjsonstring ("Persons",  service.getlistperson ()); System.out.println ("Persons");}  else if  (Action_flag.equals ("liststring")  {jsonString =  Jsontools.createjsonstring ("ListString",  service.getliststring ()); System.out.println ("liststring");}  else if  (Action_flag.equals ("Listmap"))  {jsonstring = jsontools.createjsonstring ("Listmap",  Service.getlistmaps ()); System.out.println ("Listmap");} Out.println (jsonstring); Out.flush (); Out.close ();}

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M01/6C/50/wKiom1VFzP_RsZWVAAFQfyUpEzc040.jpg "title=" Qq20150503152308.png "alt=" Wkiom1vfzp_rszwvaafqfyupezc040.jpg "/>

5. Build Android client, create a new HttpClient tool class, get the server-side JSON format data

Package com.android.myjson.http;import java.io.bytearrayoutputstream;import java.io.ioexception ;import java.io.inputstream;import java.net.httpurlconnection;import java.net.url;public  Class httputils {public httputils ()  {// todo auto-generated constructor  stub}public static string getjsoncontent (String url_path)  {try {URL  Url = new url (Url_path); httpurlconnection connection =  (HttpURLConnection)  url.openconnection (); Connection.setconnecttimeout (+); Connection.setrequestmethod ("GET"); Connection.setdoinput (True);int  Code = connection.getresponsecode ();if  (code == 200)  {return  Changeinputstream (Connection.getinputstream ());}}  catch  (exception e)  {// TODO: handle exception}return  "";} Private static string changeinputstream (Inputstream inputstream) {// TODO Auto-generated method stubString jsonString =  ""; Bytearrayoutputstream outputstream = new bytearrayoutputstream ();int len =  0;byte[] data = new byte[1024];try {while  ((Len = inputstream.read ( Data)  != -1)  {outputstream.write (Data, 0, len);} Jsonstring = new string (Outputstream.tobytearray ());}  catch  (ioexception e)  {// TODO Auto-generated catch  Blocke.printstacktrace ();} return jsonstring;}}

6. Create a new JSON tool class to parse JSON data

Package com.android.myjson.json;import java.util.arraylist;import java.util.hashmap;import  java.util.Iterator;import java.util.List;import java.util.Map;import org.json.JSONArray; Import org.json.jsonobject;import com.android.myjson.domain.person;public class jsontools  {public jsontools ()  {// TODO Auto-generated constructor stub}public  Static person getperson (string key, string jsonstring)  {Person person  = new person ();         //{"person": {"Address": "Beijing", "id" : 1001, "name": "Jack"}}try {jsonobject jsonobject = new jsonobject (jsonstring); Jsonobject personobject = jsonobject.getjsonobject ("person");p Erson.setid (PersonObject.getInt (" ID "));p Erson.setname (personobject.getstring (" name "));p erson.setaddress (personobject.getstring (" Address "));}  catch  (EXCEPTION&Nbsp;e)  {// todo: handle exception}return person;} Public static list<person> getpersons (string key, string jsonstring)   {list<person> list = new arraylist<person> ();         //{"Persons": [{"Address": "Guangxi", "id": 1001, "name": "Jack"},{"Address": "Guangdong", "id": 1002 , "name": "Rose"}]}try {            jsonobject  jsonobject = new jsonobject (jsonstring);             jsonarray jsonarray = jsonobject.getjsonarray (Key);             for  (int i = 0; i <  jsonarray.length ();  i++)  {                 jsonobject jsonobject2&nBsp;= jsonarray.getjsonobject (i);                 person person = new person ();                 person.setid (Jsonobject2.getint ("id"));                 person.setname ( Jsonobject2.getstring ("name"));                 person.setaddress (jsonobject2.getstring ("Address"));                 list.add (person);             }        } catch  ( Exception e)  {            // todo:  handle exception&nbSp;       }        return list ;} Public static list<string> getlist (string key, string jsonstring)  { List<string> list = new arraylist<string> ();try {jsonobject  Jsonobject = new jsonobject (jsonstring); Jsonarray jsonarray = jsonobject.getjsonarray (Key);for  (int i = 0; i  < jsonarray.length ();  i++)  {string msg = jsonarray.getstring (i); List.add (msg);}}  catch  (Exception e)  {// todo: handle exception}return list;} Public static list<map<string, object>> listkeymaps (String key,String  jsonstring)  {list<map<string, object>> list = new arraylist <Map<String, Object>> (TRY&NBSP;{JSONOBJECT&NBSP;JSONOBJECT&NBSP);; = new jsonobject (jsonstring); Jsonarray jsonarray = jsonobject.getjsonarray (Key);for  (int i = 0; i  < jsonarray.length ();  i++)  {JSONObject jsonObject2 =  Jsonarray.getjsonobject (i); Map<string, object> map = new hashmap<string, object> ();Iterator< String> iterator = jsonobject2.keys ();while  (Iterator.hasnext ())  {String json _key = iterator.next (); Object json_value = jsonobject2.get (Json_key);if  (json_ Value == null)  {json_value =  "";} Map.put (Json_key, json_value);} List.add (map);}}  catch  (Exception e)  {// todo: handle exception}return list;}}

7. Print out the parsed data

String Path = "Http://192.168.191.1:8080/jsonProject/servlet/JsonAction?action_flag=person"; String jsonstring = httputils.getjsoncontent (path); Person person = Jsontools.getperson ("person", jsonstring); LOG.I (TAG, person.tostring ());

Android parsing JSON data