crowd-test-service-backend/site/src/main/java/com/mooctest/crowd/site/util/FileUtil.java

package com.mooctest.crowd.site.util;

import cn.afterturn.easypoi.excel.ExcelImportUtil;
import cn.afterturn.easypoi.excel.entity.ImportParams;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.multipart.MultipartFile;

import java.io.*;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;

/**
 * @author: Diors.Po
 * @Email: 171256175@qq.com
 * @date 2019-08-05 19:57
 */
@Slf4j
public class FileUtil {
    public static final Map<String, String> FILE_TYPE_MAP = new HashMap<>(); //本系统中合法的文件类型

    static {

        //图片
        FILE_TYPE_MAP.put("ffd8ff", "jpg"); //JPEG (jpg)
        FILE_TYPE_MAP.put("89504e", "png"); //PNG (png)
        FILE_TYPE_MAP.put("474946", "gif"); //GIF (gif)

        FILE_TYPE_MAP.put("49492a", "tif"); //TIFF (tif)
        FILE_TYPE_MAP.put("492049", "tif");
        FILE_TYPE_MAP.put("4d4d00", "tif");

        FILE_TYPE_MAP.put("424d22", "bmp"); //16色位图(bmp)
        FILE_TYPE_MAP.put("424d82", "bmp"); //24位位图(bmp)
        FILE_TYPE_MAP.put("424d8e", "bmp"); //256色位图(bmp)

        //压缩文件
        FILE_TYPE_MAP.put("504b03", "zip");
        FILE_TYPE_MAP.put("504b05", "zip");
        FILE_TYPE_MAP.put("504b07", "zip");
        FILE_TYPE_MAP.put("526172", "rar");

        //文档
        FILE_TYPE_MAP.put("255044", "pdf"); //Adobe Acrobat (pdf)
        FILE_TYPE_MAP.put("504b03", "docx");//docx文件，xlsx等一致
        FILE_TYPE_MAP.put("d0cf11", "doc/dot"); //MS Excel 注意：word、msi 和 excel的文件头一样
        FILE_TYPE_MAP.put("0d444f", "doc/dot");
        FILE_TYPE_MAP.put("cf11e0", "doc/dot");
        FILE_TYPE_MAP.put("dba52d", "doc/dot");
        FILE_TYPE_MAP.put("d0cf11", "wps/wks");//WPS文字wps、表格et、演示dps都是一样的
        FILE_TYPE_MAP.put("0e574b", "wps/wks");
        FILE_TYPE_MAP.put("ff0002", "wps/wks");

        //exe可执行文件
        FILE_TYPE_MAP.put("4d5a90", "exe");
    }

    public static String save(String dirPath, MultipartFile inputFile, String fileName) throws IOException {
        byte[] bs = new byte[1024];
        int len;

        File saveDir = new File(dirPath);
        if (!saveDir.exists()) {
            saveDir.mkdirs();
        }
        if(fileName.equals("")){
            fileName = inputFile.getOriginalFilename();
        }
        String saveFilePath = saveDir.getPath() + "/"  + fileName;
        OutputStream os = new FileOutputStream( saveFilePath );
        InputStream is = inputFile.getInputStream();
        while ((len = is.read(bs)) != -1) {
            os.write(bs, 0, len);
        }

        os.close();
        is.close();

        return saveFilePath.replaceAll("\\\\", "/" );
    }

    public static boolean checkFile(InputStream inputStream){
        try {
            byte[] headBytes = new byte[3];
            inputStream.read(headBytes, 0, headBytes.length);
            String headStr = bytesToHexString(headBytes).toLowerCase();
            log.info("The Head of File: "+headStr);
//            log.info("Whether the map contain the " + headStr +": " + FILE_TYPE_MAP.containsKey(headStr));
            return FILE_TYPE_MAP.containsKey(headStr);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return true;
    }

    public static boolean checkExcel(InputStream inputStream){
        String headStr = getHeadStr(inputStream);
        log.info("The Head of File: "+headStr);
        String name = FILE_TYPE_MAP.get(headStr);
        if (name == null || (!name.contains("doc")&&(!name.contains("wps"))))
            return false;
        return true;
    }

    public static String getHeadStr(InputStream inputStream){
        try {
            byte[] headBytes = new byte[3];
            inputStream.read(headBytes, 0, headBytes.length);
            return bytesToHexString(headBytes).toLowerCase();
        } catch (IOException e) {
            throw new RuntimeException("读取文件头出错！", e);
        }
    }

    private static String bytesToHexString(byte[] src) {
        StringBuilder builder = new StringBuilder();
        if (src == null || src.length <= 0) {
            return null;
        }
        String hv;
        for (int i = 0; i < src.length; i++) {
            // 以十六进制（基数 16）无符号整数形式返回一个整数参数的字符串表示形式，并转换为大写
            hv = Integer.toHexString(src[i] & 0xFF).toUpperCase();
            if (hv.length() < 2) {
                builder.append(0);
            }
            builder.append(hv);
        }
        System.out.println("HexString: " + builder.toString());
        return builder.toString();
    }

    public static <T> List<T> importExcel(MultipartFile file, Integer titleRows, Integer headerRows, Class<T> pojoClass){
        if (file == null){
            return null;
        }
        ImportParams params = new ImportParams();
        params.setTitleRows(titleRows);
        params.setHeadRows(headerRows);
        List<T> list = null;
        try {
            list = ExcelImportUtil.importExcel(file.getInputStream(), pojoClass, params);
        }catch (NoSuchElementException e){
            log.info("excel文件不能为空");
            throw new RuntimeException("excel文件不能为空");
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        return list;
    }
}