Question

我目前正在尝试开发针对Google Chrome（4及更高版本）优化的Java Web应用程序。

我希望用户能够选择多个文件，将它们上传到服务器（使用名为uploadForm的网页中显示的表单），并在上传完成后自动重定向到另一个网页（称为上传）。

因此，我创建了一个JSP文件（ uploadForm.jsp ），其中定义了上传表单。我还使用XMLHttpRequest对象实现了文件上传过程（它是软件规范的一部分。我别无选择）

<body>
    <form id="file_form" action="upload" method="post" enctype="multipart/form-data">
        <input type="file" name="file_input[]" id="file_select" multiple webkitdirectory=""/> 
        <button type="submit" id="upload_button" >Upload</button>
    </form> 
</body>

<script type="text/javascript">

        // Get the form
        var form = document.getElementById("file_form");

        // Get the file selecter
        var fileSelect = document.getElementById("file_select");

        // Get the button which allows to upload the documents
        var uploadButton = document.getElementById("upload_button");

        // Set up the request
        var xhr = new XMLHttpRequest();

        // Create a new FormData object
        var formData = new FormData();

        form.onsubmit = function(event){

            // Prevent the form to be submitted. We want to write our 
            // own submission protocol
            event.preventDefault();

            // Update the button status during the uploading
            uploadButton.innerHTML = 'Uploading...';

            // Get the selected files from the input
            var files = fileSelect.files;

            // Loop through each of the selected files
            for(var i=0;i<files.length;i++){

                // The file contained in the file list
                var file = files[i];

                // Add the file to the request
                formData.append('file_input[]',file,file.name);

                xhr.open('POST','upload',true);  

                // Send the data
                xhr.send(formData);                 
            }
        };

        // Set up a handler for when the request finishes
        xhr.onload = function(){

            if(xhr.status===200){

                // File uploaded
                uploadButton.innerHTML = 'Uploaded';
            }else{
                alert('An error occurred.File was not uploaded');
            }
        };

    </script>

上传完成后。用户将自动重定向到另一个名为“upload”（ upload.jsp ）的网页，并由Servlet（ UploadServlet.java ）引用：

upload.jsp：

<html>
    <head>
        <title>TODO supply a title</title>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
    </head>
    <body>
        Everything ok
    </body>
</html>

UploadServlet.java：

@WebServlet(urlPatterns = {"/upload"})
public class UploadServlet extends HttpServlet {

/**
 * Handles the HTTP <code>POST</code> method.
 *
 * @param request servlet request
 * @param response servlet response
 * @throws ServletException if a servlet-specific error occurs
 * @throws IOException if an I/O error occurs
 */
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {

    System.out.println("I am in the servlet");

    RequestDispatcher dispatcher=getServletContext().getRequestDispatcher("/WEB-INF/upload.jsp");
    dispatcher.forward(request,response);
 }

所选文件已正确上传到服务器。但是，当上传完成后，用户实际上没有被重定向到“上传”网页。他仍然在“uploadForm”网页上，这不是我的预期。

你能帮帮我吗？非常感谢您的回答

Answer 1

ajax调用不会导致重定向（直接）。当你获得200个就绪状态更改后，javascript会进行重定向。您可以考虑让它返回文件已正确上传的信息，并检查是否有用于验证...

而不是在您的servlet中有一个转发。

文件上传后，AJAX不会重定向到网页 - POST方法

1 个答案: