利用commons-fileupload组件实现文件上传-实例

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一、所需要的包：

1、commons-fileupload-1.2.1.jar：

下载地址
http://commons.apache.org/downloads/download_fileupload.cgi

2、commons-io-1.4.jar：

下载地址
http://commons.apache.org/downloads/download_io.cgi

二、注意事项：

form表单里面要加上enctype="multipart/form-data"

三、代码示例

1、jsp代码：

<%@ 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>upload</title></head><body><form action="uploadServlet" method="post" enctype="multipart/form-data"><table><caption>上传实例</caption><tr><td>姓名</td><td><input type="text" name="name"></td></tr><tr><td>年龄</td><td><input type="text" name="age"></td></tr><tr><td>照片</td><td><input type="file" name="image"></td></tr><tr><td></td><td><input type="submit" value="提交"></td></tr></table></form></body></html>

2、UploadServlet代码

package servlet;import java.io.BufferedInputStream;import java.io.BufferedOutputStream;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.io.Writer;import java.util.Iterator;import java.util.List;import javax.servlet.ServletException;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.FileUploadBase.SizeLimitExceededException;import org.apache.commons.fileupload.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;import org.apache.commons.fileupload.util.Streams;/** * 上传servlet * @author lisanlai * */public class UploadServlet extends HttpServlet {private static final long serialVersionUID = 1L; public UploadServlet() { super(); }protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doPost(request, response);}@SuppressWarnings("unchecked")protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {response.setContentType("text/html"); // 设置字符编码为UTF-8, 这样支持汉字显示 response.setCharacterEncoding("UTF-8"); Writer o = response.getWriter();/** * 首先判断form的enctype是不是multipart/form-data * 同时也判断了form的提交方式是不是post * 方法：isMultipartContent(request) */if(ServletFileUpload.isMultipartContent(request)){request.setCharacterEncoding("utf-8");// 实例化一个硬盘文件工厂,用来配置上传组件ServletFileUpload DiskFileItemFactory factory = new DiskFileItemFactory();//设置文件存放的临时文件夹，这个文件夹要真实存在File fileDir = new File("../webapps/fileupload/tmp/");if(fileDir.isDirectory() && fileDir.exists()==false){fileDir.mkdir();}factory.setRepository(fileDir);//设置最大占用的内存factory.setSizeThreshold(1024000);//创建ServletFileUpload对象ServletFileUpload sfu = new ServletFileUpload(factory);sfu.setHeaderEncoding("utf-8");//设置单个文件最大值byte sfu.setFileSizeMax(102400000);//所有上传文件的总和最大值byte sfu.setSizeMax(204800000);List<FileItem> items = null;try {items = sfu.parseRequest(request);}catch (SizeLimitExceededException e) { System.out.println("文件大小超过了最大值"); } catch(FileUploadException e) { e.printStackTrace(); } //取得items的迭代器 Iterator<FileItem> iter = items==null?null:items.iterator(); //图片上传后存放的路径目录 File images = new File("D:/upload/images/");if(images.exists()==false){images.mkdirs();} //迭代items while(iter!=null && iter.hasNext()){ FileItem item = (FileItem) iter.next(); //如果传过来的是普通的表单域 if(item.isFormField()){ System.out.print("普通的表单域:"); System.out.print(new String(item.getFieldName()) + " "); System.out.println(new String(item.getString("UTF-8"))); } //文件域 else if(!item.isFormField()){ System.out.println("源图片:" + item.getName()); String fileName = item.getName().substring(item.getName().lastIndexOf("//")); BufferedInputStream in = new BufferedInputStream(item.getInputStream()); //文件存储在D:/upload/images目录下,这个目录也得存在 BufferedOutputStream out = new BufferedOutputStream( new FileOutputStream(new File(images.getAbsolutePath()+ fileName))); Streams.copy(in, out, true); o.write("文件上传成功"); } }}else { System.out.println("表单的enctype 类型错误"); } }}

3、web.xml

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"> <display-name>UploadTest</display-name> <welcome-file-list> <welcome-file>upload.jsp</welcome-file> </welcome-file-list> <servlet> <description></description> <display-name>UploadServlet</display-name> <servlet-name>UploadServlet</servlet-name> <servlet-class>servlet.UploadServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>UploadServlet</servlet-name> <url-pattern>/uploadServlet</url-pattern> </servlet-mapping></web-app>

代码下载

UploadTest.rar (151.1 KB)