通过超链接下载文件

java通过超链接下载文件

准备工作
//获取文件根目录
/**
* 获取根目录
* @return
*/
-public String getRootDirectory(){
File f = new File(DownloadCore.class.getResource("/").getPath());
String string = f.toString();
int hnwg = string.indexOf(“hnwg”);
System.out.println(hnwg);
System.out.println(string);
System.out.println(string.substring(0,hnwg+4));
String path = string.substring(0, hnwg + 4);
return path;
}

//利用递归获取一个目录下的所有文件夹
/**
* 传入路径根集合获取路径下所有文件
* @param path
* @param listFileName
*/

• public void getAllFileName(String path, ArrayList listFileName) {
  File file = new File(path);
  File[] files = file.listFiles();
  String[] names = file.list();
  if (names != null) {
  String[] completNames = new String[names.length];
  for (int i = 0; i < names.length; i++) {
  completNames[i] = path + names[i];
  }
  listFileName.addAll(Arrays.asList(completNames));
  }
  for (File a : files) {
  if (a.isDirectory()) {//如果文件夹下有子文件夹，获取子文件夹下的所有文件全路径。
  getAllFileName(a.getAbsolutePath() + “\”, listFileName);
  }
  }
  }

//对比进行找到自己的资源
/**
* 获取需要文件
* @param file
* @param listFileName
* @return
*/

• public String getPath(String file,ArrayList listFileName){

  for (String name : listFileName) {
  
      if (name.contains(file)){
  
          return name;
      }
  }
  return "";
  

  }

在Control我用的是springmvc下载的方法

-public ResponseEntity<byte[]> download(HttpServletRequest request,String name) throws IOException {

    System.out.println(name);
    String rootDirectory = downloadCore.getRootDirectory();
    ArrayList<String> listFileName = new ArrayList<String>();
    downloadCore.getAllFileName(rootDirectory,listFileName);
    String path = downloadCore.getPath(name, listFileName);

    System.out.println("结果路径"+path);
    File file = new File(path);
    byte[] body = null;
    InputStream is = new FileInputStream(file);
    body = new byte[is.available()];
    is.read(body);
    HttpHeaders headers = new HttpHeaders();
    headers.add("Content-Disposition", "attchement;filename=" + file.getName());
    HttpStatus statusCode = HttpStatus.OK;
    ResponseEntity<byte[]> entity = new ResponseEntity<byte[]>(body, headers, statusCode);
    return entity;
}