Java解析JSON

• 1. 什么是JSON?
• 2. 导入maven依赖
• 3. JSON案例文件
• 4. 示例代码
• 5. 解析结果

快速了解JSON

        
            com.alibaba
            fastjson
            1.2.78
        

{
  "sites": {
    "site": [
      {
        "id": "1",
        "name": "菜鸟教程",
        "url": "www.runoob.com"
      },
      {
        "id": "2",
        "name": "菜鸟工具",
        "url": "c.runoob.com"
      },
      {
        "id": "3",
        "name": "Google",
        "url": "www.google.com"
      },
      {
        "id": "4",
        "name": "baidu",
        "url": "www.baidu.com"
      }
    ]
  }
}

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Set;

public class 解析json {
    public static void main(String[] args) throws IOException {
        // 获取文件路径
        String jsonpath = 解析json.class.getClassLoader().getResource("testjson.json").getPath();

        // 读取文件获取内容
        BufferedReader reader = new BufferedReader(new FileReader(jsonpath));
        StringBuilder builder = new StringBuilder();
        String line ;
        while ((line = reader.readLine()) != null){
            builder.append(line);
        }

        // 使用JSON 工具转换为对象
        JSONObject jsonObject = JSON.parseObject(builder.toString());

        // 获取所有的key
        Set keys = jsonObject.keySet();
        // 根据所有的key获取value
        for (String key : keys) {
            System.out.println(key);
        }
        // 获取单个value, 这里根据JSON的结构, 逐层解析
        String sites = jsonObject.get("sites").toString();
        System.out.println(sites);

        // 继续获取内部的内容, 将sites 解析成JSON对象
        JSONObject parseObject = JSON.parseObject(sites);
        // 内部的site 中的value为数组, 这里可以直接获取JSONArray
        JSONArray jsonArray = parseObject.getJSONArray("site");
        for (Object o : jsonArray) {
            // 每一个元素又是对象
            JSONObject jo = JSONObject.parseObject(o.toString());
            System.out.println(jo.getString("id"));
            System.out.println(jo.getString("name"));
            System.out.println(jo.getString("url"));
        }
    }
}

sites
{"site":[{"name":"菜鸟教程","id":"1","url":"www.runoob.com"},{"name":"菜鸟工具","id":"2","url":"c.runoob.com"},{"name":"Google","id":"3","url":"www.google.com"},{"name":"baidu","id":"4","url":"www.baidu.com"}]}
1
菜鸟教程
www.runoob.com
2
菜鸟工具
c.runoob.com
3
Google
www.google.com
4
baidu
www.baidu.com

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