JSON parsing, json online Parsing

JSON parsing, json online Parsing

1. API

Xxx getXxx (int index): obtains the corresponding element data in the json array according to the subscript.
Xxx optXxx (int index): obtains the corresponding element data in the json array according to the subscript.
Note:
The optXxx method returns an empty string or the default value you specified when the value of the corresponding key does not exist. However, the getString method returns a null pointer exception.

 

2. Special json data parsing

{& Quot; code & quot;: 0, & quot; list & quot;: {& quot; 0 & quot;: {& quot; aid & quot;: & quot; 6008965 & quot;, & quot; author & quot;: & quot ", "coins": 170, "copyright": "Copy", "create": ""}, "1": {"aid": "6008938 ", "author": "", "coins": 404, "copyright": "Copy", "create "}}}

 

public class FilmInfo {    private int code;    private List<FilmBean> list;    public static class FilmBean{        private String aid;        private String author;        private int coins;        private String copyright;        private String create;    }}

　　

// Create the encapsulated Java object FilmInfo filmInfo = new FilmInfo (); // 2 parse jsontry {JSONObject jsonObject = new JSONObject (json); // parse int code = jsonObject at the first layer. optInt ("code"); JSONObject list = jsonObject. optJSONObject ("list"); // The first layer encapsulates filmInfo. setCode (code); List <FilmInfo. filmBean> lists = new ArrayList <> (); filmInfo. setList (lists );
// Second layer resolution for (int I = 0; I <list. length (); I ++) {JSONObject jsonObject1 = list. optJSONObject (I + ""); if (jsonObject1! = Null) {String aid = jsonObject1.optString ("aid"); String author = jsonObject1.optString ("author"); int coins = jsonObject1.optInt ("coins "); string copyright = jsonObject1.optString ("copyright"); String create = jsonObject1.optString ("create"); // Layer 2 Data encapsulation FilmInfo. filmBean filmBean = new FilmInfo. filmBean (); filmBean. setAid (aid); filmBean. setAuthor (author); filmBean. setCoins (coins); filmBean. setCopyright (copyright); filmBean. setCreate (create); lists. add (filmBean) ;}} catch (JSONException e) {e. printStackTrace ();}

　　

3. GsonFramework Technology

(1) convert the string {} In json format to a Java object
API:
FromJson (String json, Class <T> classOfT );

Step 1) import the jar package of Gson to the project. 2) create a Gson object: Gson gson = new Gson (). 3) Call the fromJson () method through the created Gson object, returns the Java object corresponding to the JSON data: ShopInfo shopInfo = gson. fromJson (json, ShopInfo. class );

 

Gson gson = new Gson();ShopInfo shopInfo = gson.fromJson(json, ShopInfo.class);

(2) convert a json string [] to a List of Java objects
API:
FromJson (String json, Type typeOfT );

Gson gson = new Gson();List<ShopInfo> shops = gson.fromJson(json, new TypeToken<List<ShopInfo>>() {}.getType());

(3) convert a Java object to a json string {}
API:
String toJson (Object src );

// 1 obtain or create the Java object ShopInfo shopInfo = new ShopInfo (1, "abalone", 250.0, "baoyu "); // 2 generate the JSON data Gson gson = new Gson (); String json = gson. toJson (shopInfo );

(4) convert the Java object List to a json string []

API:
String toJson (Object src );

// 1 obtain or create a Java object List <ShopInfo> shops = new ArrayList <> (); ShopInfo baoyu = new ShopInfo (1, "abalone", 250.0, "baoyu "); shopInfo longxia = new ShopInfo (2, "Lobster", 251.0, "longxia"); shops. add (baoyu); shops. add (longxia); // 2 generate the JSON data Gson gson = new Gson (); String json = gson. toJson (shops );

 

4. FastJson framework technology
(1) convert the string {} In json format to a Java object
API:
ParseObject (String json, Class <T> classOfT );

ShopInfo shopInfo = JSON.parseObject(json, ShopInfo.class);

(2) convert a json string [] to a List of Java objects
API:
List <T> parseArray (String json, Class <T> classOfT );

List<ShopInfo> shopInfos = JSON.parseArray(json, ShopInfo.class);

(3) convert a Java object to a json string {}
API:
String toJSONString (Object object );
Steps:
1) import the fastjson jar package
2) JSON calls the toJSONString () method to obtain the converted json data
For example:

ShopInfo shopInfo = new ShopInfo (1, "abalone", 250.0, "baoyu"); String json = JSON. toJSONString (shopInfo );

(4) convert the Java object List to a json string []
API:
String toJSONString (Object object );

List <ShopInfo> shops = new ArrayList <> (); ShopInfo baoyu = new ShopInfo (1, "abalone", 250.0, "baoyu"); ShopInfo longxia = new ShopInfo (2, "Lobster", 251.0, "longxia"); shops. add (baoyu); shops. add (longxia); String json = JSON. toJSONString (shops );