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

posted @ 2015-06-04 13:48  monsterLin  阅读(...)  评论(... 编辑 收藏
小弟博客地址迁移,欢迎戳这里查看新博客~