文件流读取

通过InputStreamReader去读取json文件。

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;


public static void main(String[] args) {
    File file = new File("D:\\test.json");
    StringBuffer stringBuffer = new StringBuffer();
    try {
        InputStreamReader reader = new InputStreamReader(new FileInputStream(file), StandardCharsets.UTF_8);
        BufferedReader bufferedReader = new BufferedReader(reader);
        bufferedReader.readLine();
        int str;
        while ((str = bufferedReader.read()) != -1) {
            stringBuffer.append((char) str);
        }
        bufferedReader.close();
        reader.close();
        System.out.println(stringBuffer);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

hutool工具读取

使用readJSON方法可以直接读取出json文件内容。

import cn.hutool.json.JSON;
import cn.hutool.json.JSONUtil;

public static void main(String[] args) {
        File file = new File("D:\\test.json");
        try {
            JSON json = JSONUtil.readJSON(file, StandardCharsets.UTF_8);
            String jsonStr = json.toJSONString(1); // indentFactor每一级别的缩进
            System.out.println(jsonStr);
            JSONArray jsonArray = JSONUtil.parseArray(jsonStr);
            ArrayList<Object> arrayList = ListUtil.toList(jsonArray);
            for (Object obj : arrayList) {
                Map<String, Object> map = (Map<String, Object>) obj;
                System.out.println(((Map<?, ?>) obj).get("STU_ID"));
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }