文件上传

http://commons.apache.org/proper/commons-fileupload/using.html

package com.xiaoxin.fileupload.servlet;import java.io.File;import java.io.IOException;import java.io.PrintWriter;import java.util.Iterator;import java.util.List;import javax.servlet.ServletContext;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.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;/** * Servlet implementation class UploadServlet */@WebServlet("/uploadServlet")public class UploadServlet extends 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/** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// 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;}// Create a factory for disk-based file itemsDiskFileItemFactory factory = new DiskFileItemFactory();// Configure a repository (to ensure a secure temp location is used)ServletContext servletContext = this.getServletConfig().getServletContext();File repository = (File) servletContext.getAttribute("javax.servlet.context.tempdir");factory.setRepository(repository);//factory.setRepository(new File(System.getProperty("java.io.tmpdir")));// Set factory constraintsfactory.setSizeThreshold(MEMORY_THRESHOLD);// Create a new file upload handlerServletFileUpload upload = new ServletFileUpload(factory);// 设置最大文件上传值        upload.setFileSizeMax(MAX_FILE_SIZE);// Set overall request size constraintupload.setSizeMax(MAX_REQUEST_SIZE);// 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 = request.getServletContext().getRealPath("./") + File.separator         + UPLOAD_DIRECTORY;                        // 如果目录不存在则创建        File uploadDir = new File(uploadPath);        if (!uploadDir.exists()) {            uploadDir.mkdir();        }// Parse the requesttry {List<FileItem> items = upload.parseRequest(request);//2.遍历items，若是一般表单域，打印信息Iterator<FileItem> iter = items.iterator();while (iter.hasNext()) {    FileItem item = iter.next();    if (item.isFormField()) {    // Process a regular form field    if (item.isFormField()) {        String name = item.getFieldName();        String value = item.getString();        System.out.println(name + ":" + value);    }        } else {    //若是文件，则保存    if (!item.isFormField()) {        String fieldName = item.getFieldName();        String fileName = item.getName();        String contentType = item.getContentType();        boolean isInMemory = item.isInMemory();        long sizeInBytes = item.getSize();                System.out.println("fieldName :" + fieldName);        System.out.println("fileName :" + fileName);        System.out.println("contentType :" + contentType);        System.out.println("isInMemory :" + isInMemory);        System.out.println("sizeInBytes :" + sizeInBytes);                String filePath = uploadPath + File.separator + fileName;        System.out.println(filePath);                        File storeFile = new File(filePath);                         item.write(storeFile);        request.setAttribute("message",                            "文件上传成功!");            }        }}} catch (Exception e) {request.setAttribute("message", "错误信息: " + e.getMessage());}request.getServletContext().getRequestDispatcher("/message.jsp").forward(request, response);}}

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title></head><body><form action="uploadServlet" method="post" enctype="multipart/form-data">File: <input type="file" name="file"/><br><br>Desc: <input type="text" name="desc"/><br><br><input type="submit", value="Submit"/></form></body></html>