file-online-preview/jodconverter-web/src/main/java/cn/keking/utils/DownloadUtils.java

package cn.keking.utils;

import cn.keking.config.ConfigConstants;
import cn.keking.hutool.URLUtil;
import cn.keking.model.FileAttribute;
import cn.keking.model.FileType;
import cn.keking.model.ReturnResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import java.io.*;
import java.net.*;
import java.nio.charset.StandardCharsets;
import java.util.UUID;

/**
 * @author yudian-it
 */
@Component
public class DownloadUtils {

    private final Logger logger = LoggerFactory.getLogger(DownloadUtils.class);

    private final String fileDir = ConfigConstants.getFileDir();

    private final FileUtils fileUtils;

    public DownloadUtils(FileUtils fileUtils) {
        this.fileUtils = fileUtils;
    }

    private static final String URL_PARAM_FTP_USERNAME = "ftp.username";
    private static final String URL_PARAM_FTP_PASSWORD = "ftp.password";
    private static final String URL_PARAM_FTP_CONTROL_ENCODING = "ftp.control.encoding";
    private static final String[] URL_PARAM_LOCALURL_START={"c:","d:","e:","f:","g:","/"};

    /**
     * @param fileAttribute fileAttribute
     * @param fileName 文件名
     * @return 本地文件绝对路径
     */
    public ReturnResponse<String> downLoad(FileAttribute fileAttribute, String  fileName) {
        String urlStr = fileAttribute.getUrl();
        String type = fileAttribute.getSuffix();
        ReturnResponse<String> response = new ReturnResponse<>(0, "下载成功!!!", "");
        UUID uuid = UUID.randomUUID();
        if (null == fileName) {
            fileName = uuid+ "."+type;
        } else { // 文件后缀不一致时，以type为准(针对simText【将类txt文件转为txt】)
            fileName = fileName.replace(fileName.substring(fileName.lastIndexOf(".") + 1), type);
        }
        String realPath = fileDir + fileName;
        File dirFile = new File(fileDir);
        if (!dirFile.exists()) {
            dirFile.mkdirs();
        }
        try {
            if(isLocalUrl(urlStr)){
                byte[] bytes = getBytesFromLocalUrl(urlStr);
                OutputStream os = new FileOutputStream(new File(realPath));
                saveBytesToOutStream(bytes, os);
            }else{
                URL url = new URL(urlStr);
                if (url.getProtocol() != null && url.getProtocol().toLowerCase().startsWith("http")) {
                    byte[] bytes = getBytesFromUrl(urlStr);
                    OutputStream os = new FileOutputStream(new File(realPath));
                    saveBytesToOutStream(bytes, os);
                } else if (url.getProtocol() != null && "ftp".equals(url.getProtocol().toLowerCase())) {
                    String ftpUsername = fileUtils.getUrlParameterReg(fileAttribute.getUrl(), URL_PARAM_FTP_USERNAME);
                    String ftpPassword = fileUtils.getUrlParameterReg(fileAttribute.getUrl(), URL_PARAM_FTP_PASSWORD);
                    String ftpControlEncoding = fileUtils.getUrlParameterReg(fileAttribute.getUrl(), URL_PARAM_FTP_CONTROL_ENCODING);
                    FtpUtils.download(fileAttribute.getUrl(), realPath, ftpUsername, ftpPassword, ftpControlEncoding);
                } else {
                    response.setCode(1);
                    response.setContent(null);
                    response.setMsg("url不能识别url" + urlStr);
                }
            }
            response.setContent(realPath);
            response.setMsg(fileName);
            if(FileType.simText.equals(fileAttribute.getType())){
                convertTextPlainFileCharsetToUtf8(realPath);
            }
            return response;
        } catch (IOException e) {
            logger.error("文件下载失败，url：{}", urlStr, e);
            response.setCode(1);
            response.setContent(null);
            if (e instanceof FileNotFoundException) {
                response.setMsg("文件不存在!!!");
            } else {
                response.setMsg(e.getMessage());
            }
            return response;
        }
    }

    public byte[] getBytesFromUrl(String urlStr) throws IOException {
        InputStream is = getInputStreamFromUrl(urlStr);
        if (is != null) {
            return getBytesFromStream(is);
        } else {
            urlStr = URLUtil.normalize(urlStr, true, true);
            is = getInputStreamFromUrl(urlStr);
            if (is == null) {
                logger.error("文件下载异常：url：{}", urlStr);
                throw new IOException("文件下载异常：url：" + urlStr);
            }
            return getBytesFromStream(is);
        }
    }

    public byte[] getBytesFromLocalUrl(String urlStr) throws IOException {
        File file = new File(urlStr);
        FileInputStream fis = new FileInputStream(file);
        ByteArrayOutputStream bos = new ByteArrayOutputStream(1024);
        byte[] b = new byte[1024];
        int n;
        while ((n = fis.read(b)) != -1) {
            bos.write(b, 0, n);
        }
        fis.close();
        byte[] data = bos.toByteArray();
        bos.close();
        return data;
    }

    public void saveBytesToOutStream(byte[] b, OutputStream os) throws IOException {
        os.write(b);
        os.close();
    }

    private InputStream getInputStreamFromUrl(String urlStr) {
        try {
            URL url = new URL(urlStr);
            URLConnection connection = url.openConnection();
            if (connection instanceof HttpURLConnection) {
                connection.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");
            }
            return connection.getInputStream();
        } catch (IOException e) {
            logger.warn("连接url异常：url：{}", urlStr);
            return null;
        }
    }

    private byte[] getBytesFromStream(InputStream is) throws IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len = 0;
        while ((len = is.read(buffer)) != -1) {
            baos.write(buffer, 0, len);
        }
        byte[] b = baos.toByteArray();
        is.close();
        baos.close();
        return b;
    }

  /**
   * 转换文本文件编码为utf8
   * 探测源文件编码,探测到编码切不为utf8则进行转码
   * @param filePath 文件路径
   */
  private static void convertTextPlainFileCharsetToUtf8(String filePath) throws IOException {
    File sourceFile = new File(filePath);
    if(sourceFile.exists() && sourceFile.isFile() && sourceFile.canRead()) {
      String encoding = null;
      try {
        FileCharsetDetector.Observer observer = FileCharsetDetector.guessFileEncoding(sourceFile);
        // 为准确探测到编码,不适用猜测的编码
        encoding = observer.isFound()?observer.getEncoding():null;
        // 为准确探测到编码,可以考虑使用GBK  大部分文件都是windows系统产生的
      } catch (IOException e) {
        // 编码探测失败,
        e.printStackTrace();
      }
      if(encoding != null && !"UTF-8".equals(encoding)){
        // 不为utf8,进行转码
        File tmpUtf8File = new File(filePath+".utf8");
        Writer writer = new OutputStreamWriter(new FileOutputStream(tmpUtf8File), StandardCharsets.UTF_8);
        Reader reader = new BufferedReader(new InputStreamReader(new FileInputStream(sourceFile),encoding));
        char[] buf = new char[1024];
        int read;
        while ((read = reader.read(buf)) > 0){
          writer.write(buf, 0, read);
        }
        reader.close();
        writer.close();
        // 删除源文件
        sourceFile.delete();
        // 重命名
        tmpUtf8File.renameTo(sourceFile);
      }
    }
  }

  /**
  * @param url url
  * @return 是否是本地文件的绝对路径
  */
  private boolean isLocalUrl(String url){
      for(String str:URL_PARAM_LOCALURL_START){
          if(url.toLowerCase().startsWith(str))
              return true;
      }
      return false;
  }
}