功能介绍：

利用 Servlet 和表单提交，选择本地文件上传到服务器。上传的文件可以是文本文件或图像文件或任何文档，不能是文件夹。

需要引入的 jar 文件：commons-fileupload-1.3.2、commons-io-2.5.jar。

下载链接：

将下载好的jar包复制到项目/WebContent/WEB-INF/lib 文件夹下：

实现代码：

fileUpload.jsp:文件上传的界面页

pageEncoding="UTF-8"%>

文件上传

文件上传

选择一个文件：

FileUploadServlet.java:文件上传处理

package com.company.project.servlet.fileupload;

import java.io.File;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.List;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;

import org.apache.commons.fileupload.FileUploadException;

import org.apache.commons.fileupload.disk.DiskFileItemFactory;

import org.apache.commons.fileupload.servlet.ServletFileUpload;

@WebServlet("/file-upload-servlet")

public class FileUploadServlet extends HttpServlet {

private static final long serialVersionUID = 1L;

// 文件上传的存储路径private static final String SAVE_PATH = "file-upload";

// 上传配置// 配置内存临界值private static final int MEMORY_THRESHOLD = 1024 * 1024 * 3; // 3MB// 配置最大文件大小private static final int MAX_FILE_SIZE = 1024 * 1024 * 40; // 40MB// 配置请求大小private static final int MAX_REQUEST_SIZE = 1024 * 1024 * 50; // 50MB

public FileUploadServlet() {

super();

}

protected void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doPost(request, response);

}

protected void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

// 检测是否为多媒体文件if (!ServletFileUpload.isMultipartContent(request)) {

// 如果不是则停止PrintWriter out = response.getWriter();

out.println("表单必须包含 enctype=multipart/form-data");

out.flush();

out.close();

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);

ServletFileUpload upload = new ServletFileUpload(factory);

// 设置上传文件最大值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");

// 创建保存路径String uploadPath = request.getServletContext().getRealPath("./") + File.separator + SAVE_PATH;

// 如果路径不存在则创建File uploadDir = new File(uploadPath);

if (!uploadDir.exists()) {

uploadDir.mkdir();

}

try {

@SuppressWarnings("unchecked")

List formItems = upload.parseRequest(request);

if (formItems != null && formItems.size() > 0) {

//迭代表单数据for (FileItem fileItem : formItems) {

//处理不在表单的字段if(!fileItem.isFormField()) {

String fileName = new File(fileItem.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 fileItem.write(storeFile);

request.setAttribute("message",

"文件上传成功!");

}

}

}

} catch (FileUploadException e) {

// TODO Auto-generated catch blocke.printStackTrace();

} catch (Exception e) {

request.setAttribute("message",

"错误信息: " + e.getMessage());

}

//文件上传完成跳转request.getServletContext().getRequestDispatcher("/page/UploadMes.jsp").forward(request, response);

}

}

UploadMes.jsp:文件传输完成跳转页

pageEncoding="UTF-8"%>

文件上传结果

${message }

效果图：