How to implement file upload in java

(1) Prepare the front page Upload.html

Form action=Upload file background interface method=”post” enctype=”multipart/form- data”

File input box

<form action="/upload" method="post" enctype="multipart/form-data">
     <input type="file" name="files">
    <input type="submit" value="上传">
</form>

(2) Add the corresponding jar package

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(3) Prepare to receive the file Servlet

url path must be consistent with the action of the form above

(4) Write the file upload background code

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws 
ServletException, IOException {
        try {
            // 配置上传参数
            DiskFileItemFactory factory = new DiskFileItemFactory();
            ServletFileUpload upload = new ServletFileUpload(factory);
            // 解析请求的内容提取文件数据
            @SuppressWarnings("unchecked")
            List<FileItem> formItems = upload.parseRequest(request);
 
            // 迭代表单数据
            for (FileItem item : formItems) {
                // 处理不在表单中的字段
                if (!item.isFormField()) {
                    String fileName = item.getName();
                    //定义上传文件的存放路径
                    String path = request.getServletContext().getRealPath("/uploadFiles");
                    //定义上传文件的完整路径
                    String filePath = String.format("%s/%s",path,fileName);
                    File storeFile = new File(filePath);
                    // 在控制台输出文件的上传路径
                    System.out.println(filePath);
                    // 保存文件到硬盘
                    item.write(storeFile);
                }
            }
        } catch (Exception ex) {
 
        }
 
    }

(5) Prepare the directory to store the uploaded files, pay attention to keep the path consistent with the above code

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