Question

这些日子我正在敲打这个问题，也许你肯定比我更了解你可以帮助我.... 然后我试着更好地解释。

我有一个javascript文件，通过库d3.js构建html代码页并将其替换为其他代码，每个部分都有不同的功能......该页面不会收费（Ajax）。在某些时候我需要允许用户将图像上传到他们的个人资料图片，所以我确保html代码诱饵

<input type="file" id="file">

和

<input type = "button" onclick = "javaScript: performAjaxSubmit ()">

PerformAjaxSubmit function（）通过xmlHttpRequest级别2将数据发送到Java Servlet，根据我的理解，这不仅可以发送字符串，还可以发送更复杂的文件等。

功能如下：

function performAjaxSubmit() {
    var sampleFile = document.getElementById("file").files[0];
    var formdata = new FormData();
    formdata.append("sampleFile", sampleFile);
    var xhr = new XMLHttpRequest();
    xhr.open("POST", "http://127.0.0.1:8080/Prova/Upload", true);
    xhr.send(formdata);
    xhr.onload = function(e) {
        if (this.status == 200) {
            alert(this.responseText);
        }
    };
}

Servlet中的代码是：

protected void doPost(HttpServletRequest request,
        HttpServletResponse response) throws ServletException, IOException {
    // Check that we have a file upload request
    System.out.println(request.getAttribute("username"));
      isMultipart = ServletFileUpload.isMultipartContent(request);
      response.setContentType("text/html");
      java.io.PrintWriter out = response.getWriter( );

      DiskFileItemFactory factory = new DiskFileItemFactory();
      // maximum size that will be stored in memory
      factory.setSizeThreshold(maxMemSize);
      // Location to save data that is larger than maxMemSize.
      factory.setRepository(new File("C:/Users/Marty/workspaceJEE/Prova/WebContent/imm/utenti"));
      filePath="C:/Users/Marty/workspaceJEE/Prova/WebContent/imm/utenti";
      // Create a new file upload handler
      ServletFileUpload upload = new ServletFileUpload(factory);
      // maximum file size to be uploaded.
      upload.setSizeMax( maxFileSize );

      try{ 
      // Parse the request to get file items.
      List fileItems = upload.parseRequest(request);

      // Process the uploaded file items
      Iterator i = fileItems.iterator();

      while ( i.hasNext () ) 
      {
         FileItem fi = (FileItem)i.next();
         if ( !fi.isFormField () )  
         {
            // Get the uploaded file parameters
            String fieldName = fi.getFieldName();
            String fileName = fi.getName();
            String contentType = fi.getContentType();
            boolean isInMemory = fi.isInMemory();
            long sizeInBytes = fi.getSize();
            // Write the file
            if( fileName.lastIndexOf("\\") >= 0 ){
               file = new File( filePath +"/"+ 
               fileName.substring( fileName.lastIndexOf("\\"))) ;
            }else{
                System.out.println(filePath + 
               fileName.substring(fileName.lastIndexOf("\\")+1));
               file = new File( filePath +"/"+  
               fileName.substring(fileName.lastIndexOf("\\")+1)) ;
            }
            fi.write( file ) ;
         }
      }

   }catch(Exception ex) {
       System.out.println(ex);
   }
}

现在（对不起，如果问题有点长）它可以工作，但问题是图像保存在我向我提供命令的路径中：

factory.setRepository(new File("C:/Users/Marty/workspaceJEE/Prova/WebContent/imm/utenti"));

如何远程保存？也就是说，一旦我加载了这样的Altrevista网站，我如何确保它们不是pià保存到C但是保存在项目的文件夹中？

我希望我解释一下。我正在使用Apache Tomcat v7.0。提前谢谢！

Answer 1

您可以使用ServletContext.getRealPath

此代码返回<context root>/upload（取决于您的部署配置）

request.getSession().getServletContext().getRealPath("/upload")

远程保存上传的映像 - Java和Tomcat

1 个答案: