1.FileUploadServlet.java文件，实现上传处理
import java.io.File; import java.io.IOException; import java.io.PrintWriter; import java.text.DecimalFormat; 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; public class FileUploadServlet extends HttpServlet { private static final long serialVersionUID = 1L; public FileUploadServlet() { super(); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { final long MAX_SIZE = 2048 * 1024 * 1024;// 设置上传文件最大值为2G，可以改为更大 // 允许上传的文件格式的列表 final String[] allowedExt = new String[] { "exe","jpg","DT" }; response.setContentType("text/html"); // 设置字符编码为UTF-8, 统一编码，处理出现乱码问题 response.setCharacterEncoding("UTF-8"); // 实例化一个硬盘文件工厂,用来配置上传组件ServletFileUpload DiskFileItemFactory dfif = new DiskFileItemFactory(); // 用以上工厂实例化上传组件 ServletFileUpload sfu = new ServletFileUpload(dfif); // 设置最大上传大小 sfu.setSizeMax(MAX_SIZE); PrintWriter out = response.getWriter(); // 从request得到所有上传域的列表 List fileList = null; try { fileList = sfu.parseRequest(request); } catch (FileUploadException e) {// 处理文件尺寸过大异常 if (e instanceof SizeLimitExceededException) { out.println("文件尺寸超过规定大小:" + MAX_SIZE + "字节<p />"); out.println("<a href="FileUpload.html" target="_top">返回</a>"); return; } e.printStackTrace(); } // 没有文件上传 if (fileList == null || fileList.size() == 0) { out.println("请选择上传文件<p />"); out.println("<a href="FileUpload.html" target="_top">返回</a>"); return; } //文件大小取两位小数 DecimalFormat digit=new DecimalFormat("0.00"); // 得到所有上传的文件 Iterator fileItr = fileList.iterator(); // 循环处理所有文件 while (fileItr.hasNext()) { FileItem fileItem = null; String path = null; double size = 0; // 得到当前文件 fileItem = (FileItem) fileItr.next(); // 忽略简单form字段而不是上传域的文件域(<input type="text" />等) if (fileItem == null || fileItem.isFormField()) { continue; } // 得到文件的大小，K为单位并保留两位小数 size = (double)fileItem.getSize()/1024; if ("".equals(path) || size == 0) { out.println("<html><head><title>上传处理界面</title></head>"); out.println("请选择上传文件<p />"); out.println("<a href="FileUpload.html" target="_top">返回</a>"); out.println("</html>"); return; } // 得到文件的完整路径 path = fileItem.getName(); // 得到去除路径的文件名 String t_name = path.substring(path.lastIndexOf("") + 1); // 得到文件的扩展名(无扩展名时将得到全名) String t_ext = t_name.substring(t_name.lastIndexOf(".") + 1); // 拒绝接受规定文件格式之外的文件类型 int allowFlag = 0; int allowedExtCount = allowedExt.length; for (; allowFlag < allowedExtCount; allowFlag++) { if (allowedExt[allowFlag].equals(t_ext)) break; } if (allowFlag == allowedExtCount) { out.println("<html><head><title>上传处理界面</title></head>"); out.println("请上传以下类型的文件<p />"); for (allowFlag = 0; allowFlag < allowedExtCount; allowFlag++) out.println("*." + allowedExt[allowFlag] + ""); out.println("<p /><a href="FileUpload.html" target="_top">返回</a>"); out.println("</html>"); return; } try { // 保存文件到服务器根目录下 fileItem.write(new File(""+t_name)); System.out.println(t_name); out.println("<html><head><title>上传处理界面</title></head>"); out.println("文件名称为：" + path + "<br>"); out.println("文件上传成功， 已保存为: " + t_name + "<br>"+" 文件大小: " + digit.format(size) + "K <p />"); out.println("<a href="FileUpload.html" target="_top">继续上传</a>"); out.println("</html>"); } catch (Exception e) { e.printStackTrace(); } } } }
2.FileUpload.html文件，实现上传页面。
<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>文件上传</title> </head> <body> <form action="FileUploadServlet" method="post" enctype="multipart/form-data"> <input type="file" size="30" name="file01" /><br> <pre> <input name="submit" type="submit" value="上传"> <input name="reset" type="reset" value="重置"> </pre> </form> </body> </html>
3.配置web.xml文件中的的servlet和过滤器，过滤器解决上传文件名为中文时出现乱码。
<"1.0" encoding="UTF-8"?> <web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <servlet> <display-name>FileUploadServlet</display-name> <servlet-name>FileUploadServlet</servlet-name> <servlet-class>FileUploadServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>FileUploadServlet</servlet-name> <url-pattern>/FileUploadServlet</url-pattern> </servlet-mapping> <filter> <filter-name>setCharacterEncoding </filter-name> <filter-class>com.xulu.EncodingChange</filter-class> <init-param> <param-name>ignore </param-name> <param-value>true </param-value> </init-param> <init-param> <param-name>encoding </param-name> <param-value>UTF-8 </param-value> </init-param> </filter> <filter-mapping> <filter-name>setCharacterEncoding </filter-name> <url-pattern>/* </url-pattern> </filter-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> <login-config> <auth-method>BASIC</auth-method> </login-config> </web-app>
4.过滤器文件EncodingChange.java和setCharacterEncoding.java分别如下，并且在根目录下的WEB-INFclassescomxulu文件夹中放入他它们编译生成的.class文件
package com.xulu; import java.io.IOException; import javax.servlet.*; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class EncodingChange implements Filter { protected String encoding = null; protected FilterConfig filterconfig = null; protected boolean ignore = true; public void destroy() { this.encoding = null; this.filterconfig = null; } public void doFilter(ServletRequest requests, ServletResponse responses, FilterChain chain) throws IOException, ServletException { // TODO Auto-generated method stub HttpServletRequest request = (HttpServletRequest) requests; HttpServletResponse response = (HttpServletResponse) responses; if (ignore || request.getCharacterEncoding() == null) { String encoding = selectEncoding(request); if (encoding != null) { request.setCharacterEncoding(encoding); request.getSession().getAttribute("Login_Student"); request.getSession().getAttribute("Login_Teacher"); request.getSession().getAttribute("Login_Admin"); } } chain.doFilter(request, response); } public void init(FilterConfig filterconfig) throws ServletException { // TODO Auto-generated method stub this.filterconfig = filterconfig; this.encoding = filterconfig.getInitParameter("encoding"); String value = filterconfig.getInitParameter("ignore"); if (value == null) { this.ignore = true; } else if (value.equalsIgnoreCase("true")) { this.ignore = true; } else if (value.equalsIgnoreCase("yes")) { this.ignore = true; } else { this.ignore = false; } } public String selectEncoding(ServletRequest request) { return this.encoding; } } 和 package com.xulu; import java.io.IOException; import javax.servlet.*; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class setCharacterEncoding implements Filter{ protected String encoding=null; protected FilterConfig filterconfig=null; protected boolean ignore=true; public void destroy() { this.encoding=null; this.filterconfig=null; } public void doFilter(ServletRequest requests, ServletResponse responses, FilterChain chain) throws IOException, ServletException { // TODO Auto-generated method stub HttpServletRequest request=(HttpServletRequest)requests; HttpServletResponse response=(HttpServletResponse)responses; if(ignore||request.getCharacterEncoding()==null){ String encoding=selectEncoding(request); if(encoding!=null){ request.setCharacterEncoding(encoding); request.getSession().getAttribute("Login_Student"); request.getSession().getAttribute("Login_Teacher"); request.getSession().getAttribute("Login_Admin"); } } chain.doFilter(request, response); } public void init(FilterConfig filterconfig) throws ServletException { // TODO Auto-generated method stub this.filterconfig = filterconfig; this.encoding = filterconfig.getInitParameter("encoding"); String value = filterconfig.getInitParameter("ignore"); if (value == null) { this.ignore = true; } else if (value.equalsIgnoreCase("true")) { this.ignore = true; } else if (value.equalsIgnoreCase("yes")) { this.ignore = true; } else { this.ignore = false; } } public String selectEncoding(ServletRequest request){ return this.encoding; } }
5.在浏览器中就可以实现页面的上传了，访问http://localhost:8080/**/FileUpload.html就可以了。其中**为自己命名的web文件夹，如DoUpload，上面的文件都在该目录里，且DoUpload文件夹放在Tomcat的webapp文件夹下。
补充：在上述所有步骤之前需引入三个.jar文件，分别为commons-fileupload-1.2.1.jar，commons-io-1.4.jar和servlet-api.jar网上可以下载到
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