HTML5文件上传到Java Servlet

我的问题是这样说的。我目前正在使用Uploadify(Flash Ajax)来完成Servlet(Commons Upload w / OWASP ESAPI overlay)，但我很想知道如何在HTML5支持下建立HTML5，或者说HTML5支持Flash。

我知道如何使HTML5 DnD工作，但我不能弄清楚Java Servlet连接和/或后端的机制。我搜索了很多地方，但我找不到任何答案，所以任何帮助，赞赏。

解决方法@H_403_6@

I know how to get the HTML5 DnD working,but I can’t quite figure out the mechanics of a Java Servlet connection and/or backend.

与使用常规的< form enctype =“multipart / form-data”>没有什么不同。所有你需要做的是让HTML5 / JS代码发送一个多部分/表单数据请求，其中包含已删除的文件，与使用普通的< input type =“file”发送的完全相同的请求类型>领域。我会假设你不知道如何通过HTML5 / JS实现。您可以使用新的HTML5 File API，XHR2 FormData和XMLHttpRequestUpload API。

这是一个启动例子，说明你的drop事件处理程序应该如下所示：

function dropUpload(event) {
    event.stopPropagation();
    event.preventDefault();

    var formData = new FormData();
    formData.append("file",event.dataTransfer.files[0]);

    var xhr = new XMLHttpRequest();
    xhr.open("POST","uploadServlet");
    xhr.send(formData);
}

而已。此示例假定servlet在/ uploadServlet的URL模式上映射。在这个例子中，该文件可以通过Apache Commons FileUpload的方式作为具有文件名称的FileItem实例。

对于更高级的东西，例如附加事件处理程序来监视进度，等等，请检查以下博客：

> HTML5 Drag and Drop Upload and File API Tutorial
> HTML5 File Upload With Progress

我已经用以下SSCCE打了一些它：

<!DOCTYPE html>
<html lang="en">
    <head>
        <title>HTML5 drag'n'drop file upload with Servlet</title>
        <script>
            window.onload = function() {
                var dropBox = document.getElementById("dropBox");
                dropBox.addEventListener("dragenter",noop,false);
                dropBox.addEventListener("dragexit",false);
                dropBox.addEventListener("dragover",false);
                dropBox.addEventListener("drop",dropUpload,false);
            }

            function noop(event) {
                event.stopPropagation();
                event.preventDefault();
            }

            function dropUpload(event) {
                noop(event);
                var files = event.dataTransfer.files;

                for (var i = 0; i < files.length; i++) {
                    upload(files[i]);
                }
            }

            function upload(file) {
                document.getElementById("status").innerHTML = "Uploading " + file.name;

                var formData = new FormData();
                formData.append("file",file);

                var xhr = new XMLHttpRequest();
                xhr.upload.addEventListener("progress",uploadProgress,false);
                xhr.addEventListener("load",uploadComplete,false);
                xhr.open("POST","uploadServlet",true); // If async=false,then you'll miss progress bar support.
                xhr.send(formData);
            }

            function uploadProgress(event) {
                // Note: doesn't work with async=false.
                var progress = Math.round(event.loaded / event.total * 100);
                document.getElementById("status").innerHTML = "Progress " + progress + "%";
            }

            function uploadComplete(event) {
                document.getElementById("status").innerHTML = event.target.responseText;
            }
        </script>
        <style>
            #dropBox {
                width: 300px;
                height: 200px;
                border: 1px solid gray;
                border-radius: 5px;
                padding: 5px;
                color: gray;
            }
        </style>
    </head>
    <body>
        <div id="dropBox">Drag and drop a file here...</div>
        <div id="status"></div>
    </body>
</html>

而这个UploadServlet利用新的Servlet 3.0 HttpServletRequest#getPart()API：

@MultipartConfig
@WebServlet("/uploadServlet")
public class UploadServlet extends HttpServlet {

    @Override
    protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException {
        Part file = request.getPart("file");
        String filename = getFilename(file);
        InputStream filecontent = file.getInputStream();
        // ... Do your file saving job here.

        response.setContentType("text/plain");
        response.setCharacterEncoding("UTF-8");
        response.getWriter().write("File " + filename + " successfully uploaded");
    }

    private static String getFilename(Part part) {
        for (String cd : part.getHeader("content-disposition").split(";")) {
            if (cd.trim().startsWith("filename")) {
                String filename = cd.substring(cd.indexOf('=') + 1).trim().replace("\"","");
                return filename.substring(filename.lastIndexOf('/') + 1).substring(filename.lastIndexOf('\\') + 1); // MSIE fix.
            }
        }
        return null;
    }
}

也可以看看：

> How to upload files to server using JSP/Servlet?

原文链接：https://www.f2er.com/html5/169046.html

HTML5文件上传到Java Servlet

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