分享Spring的下载组件

package com.hnust.common.controller;
 
import org.apache.commons.io.FileUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.RestController;
 
import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
 
/**
 * Created by Heweipo on 2016/5/27.
 * <p>
 * 下载通用控制器
 */
@RestController
public class DownloadController extends BaseController {
 
  /**
   * 下载文件通用方法
   *
   * @param file 文件对象
   * @return 文件字节流
   */
  public ResponseEntity<byte[]> export(File file) {
    return export(file.getName(), file);
  }
 
 
  /**
   * 下载文件通用方法
   *
   * @param fileName 文件名称
   * @param file   文件对象
   * @return 文件字节流
   */
  public ResponseEntity<byte[]> export(String fileName, File file) {
 
    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
 
    headers.setContentDispositionFormData("attachment", encodeFileName(fileName));
    ResponseEntity<byte[]> rs = null;
    try {
      // 这里不能使用 HttpStatus.CREATED 201 是因为 IE Edge 无法识别，但是Firefox chrome 没问题
      rs = new ResponseEntity<>(FileUtils.readFileToByteArray(file),
          headers, HttpStatus.OK);
    } catch (IOException e) {
      //throw new CommonException(ResponseStatusEnum.FILE_ERROR, e);
    }
    return rs;
  }
 
  /**
   * 下载文件的名称，这个是在浏览器那里显示的名称
   *
   * @param fileName 文件名称
   * @return 加码的文件名称
   * <p>
   * IE
   * Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko
   * <p>
   * Edge
   * Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2486.0 Safari/537.36 Edge/13.10586
   * <p>
   * Firefox
   * Mozilla/5.0 (Windows NT 10.0; WOW64; rv:46.0) Gecko/20100101 Firefox/46.0
   * <p>
   * Chrome
   * Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/47.0.2526.106 Safari/537.36
   */
  private String encodeFileName(String fileName) {
    String name = fileName;
    try {
      String agent = request.getHeader("USER-AGENT").toLowerCase();
      if (null != agent && (agent.contains("msie") || agent.contains("edge"))) { // IE edge
        name = URLEncoder.encode(fileName, "UTF-8");
      } else if (agent.contains("safari") || agent.contains("chrome") || agent.contains("firefox")) { // safari chrome firefox
        name = new String(fileName.getBytes("UTF-8"), "iso-8859-1");
      } else { // IE10 IE11
        name = URLEncoder.encode(fileName, "UTF-8");
      }
      // 把加号还原为空格(IE Edge 有问题)
      name = name.replace("+", "%20");
    } catch (UnsupportedEncodingException e) {
      //throw new CommonException(ResponseStatusEnum.FAILURE, e);
    }
    return name;
  }
 
 
}