JAVA解析JSON數據

時間 2019-11-17

標籤 java 解析 json 數據欄目 Java 简体版

原文原文鏈接

在使用第三方api的使用，有時候會從網絡中得到json數據，因此說咱們將如何解析json數據？javascript

下面小編將經過如下幾點來進行json的講解html

1.什麼是JSON？（http://www.json.org/）java

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.git

（圖片來自：http://www.cnblogs.com/xiaoluo501395377/p/3446605.html）github

2.Json數據類型json

2-1.json對象api

2-2.json數組數組

ps：JSONObject與JSONArray的區別網絡

（JSON數組）eclipse

（JSON數組）

3.解析JSON數據（小編使用的GSON進行json數據的解析）

3-1 【JSONObject的解析】

下面是一個json文件：

{
    "resultcode": "200",
    "reason": "successed!",
    "result": {
        "sk": {
            "temp": "24",
            "wind_direction": "西南風",
            "wind_strength": "2級",
            "humidity": "51%",
            "time": "10:11"
        },
        "today": {
            "temperature": "16℃~27℃",
            "weather": "陰轉多雲",
            "weather_id": {
                "fa": "02",
                "fb": "01"
            },
            "wind": "西南風3-4 級",
            "week": "星期四",
            "city": "濱州",
            "date_y": "2015年06月04日",
            "dressing_index": "溫馨",
            "dressing_advice": "建議着長袖T恤、襯衫加單褲等服裝。年老體弱者宜着針織長袖襯衫、馬甲和長褲。",
            "uv_index": "最弱",
            "comfort_index": "",
            "wash_index": "較適宜",
            "travel_index": "",
            "exercise_index": "較適宜",
            "drying_index": ""
        },
        "future": [
            {
                "temperature": "16℃~27℃",
                "weather": "陰轉多雲",
                "weather_id": {
                    "fa": "02",
                    "fb": "01"
                },
                "wind": "西南風3-4 級",
                "week": "星期四",
                "date": "20150604"
            },
            {
                "temperature": "20℃~32℃",
                "weather": "多雲轉晴",
                "weather_id": {
                    "fa": "01",
                    "fb": "00"
                },
                "wind": "西風3-4 級",
                "week": "星期五",
                "date": "20150605"
            },
            {
                "temperature": "23℃~35℃",
                "weather": "多雲轉陰",
                "weather_id": {
                    "fa": "01",
                    "fb": "02"
                },
                "wind": "西南風3-4 級",
                "week": "星期六",
                "date": "20150606"
            },
            {
                "temperature": "20℃~33℃",
                "weather": "多雲",
                "weather_id": {
                    "fa": "01",
                    "fb": "01"
                },
                "wind": "北風微風",
                "week": "星期日",
                "date": "20150607"
            },
            {
                "temperature": "22℃~34℃",
                "weather": "多雲",
                "weather_id": {
                    "fa": "01",
                    "fb": "01"
                },
                "wind": "西南風3-4 級",
                "week": "星期一",
                "date": "20150608"
            },
            {
                "temperature": "22℃~33℃",
                "weather": "陰",
                "weather_id": {
                    "fa": "02",
                    "fb": "02"
                },
                "wind": "西南風3-4 級",
                "week": "星期二",
                "date": "20150609"
            },
            {
                "temperature": "22℃~33℃",
                "weather": "多雲",
                "weather_id": {
                    "fa": "01",
                    "fb": "01"
                },
                "wind": "南風3-4 級",
                "week": "星期三",
                "date": "20150610"
            }
        ]
    },
    "error_code": 0
}

咱們進行解析（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();  //建立json解析器
        try {
            JsonObject json=(JsonObject) parse.parse(new FileReader("weather.json"));  //建立jsonObject對象
            System.out.println("resultcode:"+json.get("resultcode").getAsInt());  //將json數據轉爲爲int型的數據
            System.out.println("reason:"+json.get("reason").getAsString());     //將json數據轉爲爲String型的數據
            
            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();
        }
    }
}

輸出結果：

3-2 【JSONArray的解析】

下面是一個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
}

咱們進行解析：

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();  //建立JSON解析器
            JsonObject object=(JsonObject) parser.parse(new FileReader("test.json"));  //建立JsonObject對象
            System.out.println("cat="+object.get("cat").getAsString()); //將json數據轉爲爲String型的數據
            System.out.println("pop="+object.get("pop").getAsBoolean()); //將json數據轉爲爲boolean型的數據
            
            JsonArray array=object.get("language").getAsJsonArray();    //獲得爲json的數組
            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();
        }
    }
}

輸出結果：

3-3 【分析】

咱們經過Gson進行解析，因此在使用前須要導入Gson.jar

解析json數據時，

1.須要進行建立Gson解析器

2.建立JSONObject對象

3.將json數據轉爲爲相應的數據

4.源代碼下載：

https://github.com/monsterLin/TestReadJSON