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javaweb文件上传

此文仅作笔记

<%@ page contentType="text/html;charset=UTF-8" language="java" %>    
   
    
        
    
   

java代码

package example.servlet;import org.apache.commons.fileupload.FileItem;import org.apache.commons.fileupload.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;import javax.servlet.annotation.WebServlet;import java.io.File;import java.io.IOException;import java.io.PrintWriter;import java.util.List;@WebServlet("/servletForUpload")public class servletForUpload extends javax.servlet.http.HttpServlet {
       private static final long serialVersionUID = 1L;    // 上传文件存储目录    private static final String UPLOAD_DIRECTORY = "upload";    // 上传配置    private static final int MEMORY_THRESHOLD = 1024 * 1024 * 3;  // 3MB    private static final int MAX_FILE_SIZE = 1024 * 1024 * 40; // 40MB    private static final int MAX_REQUEST_SIZE = 1024 * 1024 * 50; // 50MB    /**     * 上传数据及保存文件     */    protected void doPost(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, IOException {
           request.setCharacterEncoding("utf-8");        // 检测是否为多媒体上传        if (!ServletFileUpload.isMultipartContent(request)) {
               // 如果不是则停止            PrintWriter writer = response.getWriter();            writer.println("Error: 表单必须包含 enctype=multipart/form-data");            writer.flush();            return;        }        // 配置上传参数        DiskFileItemFactory factory = new DiskFileItemFactory();        // 设置内存临界值 - 超过后将产生临时文件并存储于临时目录中        factory.setSizeThreshold(MEMORY_THRESHOLD);        // 设置临时存储目录        factory.setRepository(new File(System.getProperty("java.io.tmpdir")));        ServletFileUpload upload = new ServletFileUpload(factory);        // 设置最大文件上传值        upload.setFileSizeMax(MAX_FILE_SIZE);        // 设置最大请求值 (包含文件和表单数据)        upload.setSizeMax(MAX_REQUEST_SIZE);        // 中文处理        upload.setHeaderEncoding("UTF-8");        // 构造临时路径来存储上传的文件        // 这个路径相对当前应用的目录        String uploadPath = getServletContext().getRealPath("/") + File.separator + UPLOAD_DIRECTORY;        System.out.println("upload path: " + uploadPath);        // 如果目录不存在则创建        File uploadDir = new File(uploadPath);        if (!uploadDir.exists()) {
               System.out.println("创建目录");            uploadDir.mkdir();        }        try {
               // 解析请求的内容提取文件数据            //告诉编译器忽略 unchecked 警告信息，如使用List，ArrayList等未进行参数化产生的警告信息            @SuppressWarnings("unchecked")            List
   
     formItems = upload.parseRequest(request);            if (formItems != null && formItems.size() > 0) {
                   // 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 = new File(item.getName()).getName();                        String filePath = uploadPath + File.separator + 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);//                        request.setAttribute("message",//                                "文件上传成功!");                    }                }            }        } catch (Exception ex) {
   //            request.setAttribute("message",//                    "错误信息: " + ex.getMessage());        }        // 跳转到 index.jsp        getServletContext().getRequestDispatcher("/index.jsp").forward(                request, response);    }    protected void doGet(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, IOException {
           doPost(request, response);    }}
   

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