Springboot上传.Json文件参数，转成json数据

 一：在外面的日常开发中会使用到.json文件进行传参，因为有可能参数的数据很大

如下：

像这种.json文件的传输，需要我们解析出来，我这里用到的是MultipartFile表单方式传输

二：解析如下，解析到字符串，也可以去除换行符

三：下面就是转json数据了，首先转成file再转json

import org.springframework.web.multipart.MultipartFile;

import java.io.*;

/**
 * @author lrx
 * @description: TODO  读取json文件工具类
 * @date 2021/7/19 10:42
 */
public class ReadJsonFileUtils {
    //读取json文件
    public static String readJsonFile(MultipartFile fileName) throws Exception {
        File file = multipartFileToFile(fileName);
        String jsonStr = "";
        try {
            FileReader fileReader = new FileReader(file);
            Reader reader = new InputStreamReader(new FileInputStream(file), "utf-8");
            int ch = 0;
            StringBuffer sb = new StringBuffer();
            while ((ch = reader.read()) != -1) {
                sb.append((char) ch);
            }
            fileReader.close();
            reader.close();
            jsonStr = sb.toString();
            return jsonStr;
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * MultipartFile 转 File
     *
     * @param file
     * @throws Exception
     */
    public static File multipartFileToFile(MultipartFile file) throws Exception {

        File toFile = null;
        if (file.equals("") || file.getSize() <= 0) {
            file = null;
        } else {
            InputStream ins = null;
            ins = file.getInputStream();
            toFile = new File(file.getOriginalFilename());
            inputStreamToFile(ins, toFile);
            ins.close();
        }
        return toFile;
    }

    //获取流文件
    private static void inputStreamToFile(InputStream ins, File file) {
        try {
            OutputStream os = new FileOutputStream(file);
            int bytesRead = 0;
            byte[] buffer = new byte[8192];
            while ((bytesRead = ins.read(buffer, 0, 8192)) != -1) {
                os.write(buffer, 0, bytesRead);
            }
            os.close();
            ins.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}