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  • JAVA解析JSON数据

      在使用第三方api的使用,有时候会从网络中获得json数据,所以说我们将如何解析json数据?

      下面小编将通过以下几点来进行json的讲解

    1.什么是JSON? (http://www.json.org/

    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.

    image

    image

    (图片来自:http://www.cnblogs.com/xiaoluo501395377/p/3446605.html

    2.Json数据类型

    2-1.json对象

    image

    2-2.json数组

    image

    ps:JSONObject与JSONArray的区别

    image(JSON数组)

    imageJSON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:

    {
        "resultcode": "200",
        "reason": "successed!",
        "result": {
            "sk": {
                "temp": "24",
                "wind_direction": "西南风",
                "wind_strength": "2级",
                "humidity": "51%",
                "time": "10:11"
            },
            "today": {
                "temperature": "16℃~27℃",
                "weather": "阴转多云",
                "weather_id": {
                    "fa": "02",
                    "fb": "01"
                },
                "wind": "西南风3-4 级",
                "week": "星期四",
                "city": "滨州",
                "date_y": "2015年06月04日",
                "dressing_index": "舒适",
                "dressing_advice": "建议着长袖T恤、衬衫加单裤等服装。年老体弱者宜着针织长袖衬衫、马甲和长裤。",
                "uv_index": "最弱",
                "comfort_index": "",
                "wash_index": "较适宜",
                "travel_index": "",
                "exercise_index": "较适宜",
                "drying_index": ""
            },
            "future": [
                {
                    "temperature": "16℃~27℃",
                    "weather": "阴转多云",
                    "weather_id": {
                        "fa": "02",
                        "fb": "01"
                    },
                    "wind": "西南风3-4 级",
                    "week": "星期四",
                    "date": "20150604"
                },
                {
                    "temperature": "20℃~32℃",
                    "weather": "多云转晴",
                    "weather_id": {
                        "fa": "01",
                        "fb": "00"
                    },
                    "wind": "西风3-4 级",
                    "week": "星期五",
                    "date": "20150605"
                },
                {
                    "temperature": "23℃~35℃",
                    "weather": "多云转阴",
                    "weather_id": {
                        "fa": "01",
                        "fb": "02"
                    },
                    "wind": "西南风3-4 级",
                    "week": "星期六",
                    "date": "20150606"
                },
                {
                    "temperature": "20℃~33℃",
                    "weather": "多云",
                    "weather_id": {
                        "fa": "01",
                        "fb": "01"
                    },
                    "wind": "北风微风",
                    "week": "星期日",
                    "date": "20150607"
                },
                {
                    "temperature": "22℃~34℃",
                    "weather": "多云",
                    "weather_id": {
                        "fa": "01",
                        "fb": "01"
                    },
                    "wind": "西南风3-4 级",
                    "week": "星期一",
                    "date": "20150608"
                },
                {
                    "temperature": "22℃~33℃",
                    "weather": "阴",
                    "weather_id": {
                        "fa": "02",
                        "fb": "02"
                    },
                    "wind": "西南风3-4 级",
                    "week": "星期二",
                    "date": "20150609"
                },
                {
                    "temperature": "22℃~33℃",
                    "weather": "多云",
                    "weather_id": {
                        "fa": "01",
                        "fb": "01"
                    },
                    "wind": "南风3-4 级",
                    "week": "星期三",
                    "date": "20150610"
                }
            ]
        },
        "error_code": 0
    }
    

    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:

    image

    3-2 【JSONArray的解析】

    下面是一个json文件

    {
        "cat":"it",
        "language":[
            {"id":1,"ide":"eclipse","name":Java},
            {"id":2,"ide":"XCode","name":"Swift"},
            {"id":3,"ide":"Visual Stdio","name":"C#"}     
        ],
        "pop":true
    }

    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:

    image

    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

    4.源代码下载:

    https://github.com/monsterLin/TestReadJSON

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  • 原文地址:https://www.cnblogs.com/boy1025/p/4551593.html
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