JAVA解析JSON数据

1.什么是JSON？（http://www.json.org/）<img src="/up_pic/201809/020957329808.png" title="020957329808.png" alt="1.png"/>JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for humans to read and write. It is easy for machines to parse and generate. It is based on a subset of the JavaScript Programming Language, Standard ECMA-262 3rd Edition - December 1999. JSON is a text format that is completely language independent but uses conventions that are familiar to programmers of the C-family of languages, including C, C++, C#, Java, JavaScript, Perl, Python, and many others. These properties make JSON an ideal data-interchange language.（图片来自：http://www.cnblogs.com/xiaoluo501395377/p/3446605.html）2.Json数据类型2-1.json对象<img src="/up_pic/201809/020957403341.png" title="020957403341.png" alt="2.png"/>2-2.json数组<img src="/up_pic/201809/020957442924.png" title="020957442924.png" alt="3.png"/>ps：JSONObject与JSONArray的区别<img src="/up_pic/201809/020957531923.png" title="020957531923.png" alt="4.png"/>（JSON数组）<img src="/up_pic/201809/020957596592.png" title="020957596592.png" alt="5.png"/>（JSON数组）3.解析JSON数据（小编使用的GSON进行json数据的解析）3-1 【JSONObject的解析】下面是一个json文件：我们进行解析（解析一部分）：package cn.edu.bzu.json;import java.io.FileNotFoundException;import java.io.FileReader;import com.google.gson.JsonArray;import com.google.gson.JsonIOException;import com.google.gson.JsonObject;import com.google.gson.JsonParser;import com.google.gson.JsonSyntaxException;public class Read { public static void main(String args[]){ JsonParser parse =new JsonParser(); //创建json解析器 try { JsonObject json=(JsonObject) parse.parse(new FileReader("weather.json")); //创建jsonObject对象 System.out.println("resultcode:"+json.get("resultcode").getAsInt()); //将json数据转为为int型的数据 System.out.println("reason:"+json.get("reason").getAsString()); //将json数据转为为String型的数据 JsonObject result=json.get("result").getAsJsonObject(); JsonObject today=result.get("today").getAsJsonObject(); System.out.println("temperature:"+today.get("temperature").getAsString()); System.out.println("weather:"+today.get("weather").getAsString()); } catch (JsonIOException e) { e.printStackTrace(); } catch (JsonSyntaxException e) { e.printStackTrace(); } catch (FileNotFoundException e) { e.printStackTrace(); } }}输出结果：<img src="/up_pic/201809/020958076273.png" title="020958076273.png" alt="6.png"/>3-2 【JSONArray的解析】下面是一个json文件复制代码{ "cat":"it", "language":[ {"id":1,"ide":"eclipse","name":Java}, {"id":2,"ide":"XCode","name":"Swift"}, {"id":3,"ide":"Visual Stdio","name":"C#"} ], "pop":true}复制代码我们进行解析：package cn.edu.bzu.json;import java.io.FileNotFoundException;import java.io.FileReader;import com.google.gson.JsonArray;import com.google.gson.JsonIOException;import com.google.gson.JsonObject;import com.google.gson.JsonParser;import com.google.gson.JsonSyntaxException;public class ReadJSON { public static void main(String args[]){ try { JsonParser parser=new JsonParser(); //创建JSON解析器 JsonObject object=(JsonObject) parser.parse(new FileReader("test.json")); //创建JsonObject对象 System.out.println("cat="+object.get("cat").getAsString()); //将json数据转为为String型的数据 System.out.println("pop="+object.get("pop").getAsBoolean()); //将json数据转为为boolean型的数据 JsonArray array=object.get("language").getAsJsonArray(); //得到为json的数组 for(int i=0;i<array.size();i++){ System.out.println("---------------"); JsonObject subObject=array.get(i).getAsJsonObject(); System.out.println("id="+subObject.get("id").getAsInt()); System.out.println("name="+subObject.get("name").getAsString()); System.out.println("ide="+subObject.get("ide").getAsString()); } } catch (JsonIOException e) { e.printStackTrace(); } catch (JsonSyntaxException e) { e.printStackTrace(); } catch (FileNotFoundException e) { e.printStackTrace(); } }}输出结果：3-3 【分析】我们通过Gson进行解析，所以在使用前需要导入Gson.jar解析json数据时，1.需要进行创建Gson解析器2.创建JSONObject对象3.将json数据转为为相应的数据