GSON parses JSON and gsonjson

GSON parses JSON and gsonjson

The GSON open-source library provided by Google makes parsing JSON data easy to imagine. To use GSON, you must add a GSON jar package to the project. First, download the GSON resource package.

Address: https://github.com/google/gson

GSON is powerful in that it can automatically map a json string into an object, so that we do not need to write code for parsing. For example, data in json format is as follows:

{"Name": "tom", "age": "20 "}

Then we can define a Person class and add the name and age fields. Then, simply call the following code to automatically parse json data into a Person object:
Gson gson = new Gson ();
Person person = gson. fromJson (jsonData, Person. class );

If you want to parse a json array, it will be a little troublesome. We need to use TypeToken to pass the expected data type to fromJson (), as shown below:

List <Person> people = gson. fromJson (jsonData, new TypeToken <List <Person> () {}. getType ());
Well, the basic usage is like this. Let's try it. First add an App class and add the fields id, name, and version, as shown below::

package com.jack.networktest;    public class App {        private String id;      private String name;      private String version;      public String getId() {          return id;      }      public void setId(String id) {          this.id = id;      }      public String getName() {          return name;      }      public void setName(String name) {          this.name = name;      }      public String getVersion() {          return version;      }      public void setVersion(String version) {          this.version = version;      }              }  

Parsing Code:

// Use the JSONWithGSON (String jsonData) method to parse the private void parseJSONWithGSON (String jsonData) {Gson gson = new Gson (); List <App> appList = gson. fromJson (jsonData, new TypeToken <List <App> (){}. getType (); for (App app: appList) {Log. d ("MainActivity", "id is" + app. getId (); Log. d ("MainActivity", "name is" + app. getName (); Log. d ("MainActivity", "version is" + app. getVersion ());}}