用fileupload组件实现的大文件上传简单实例

2020-07-27 21:26:48

字体：大中小

来源：转载

供稿：网友

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] + "&nbsp;&nbsp;&nbsp;"); 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。

<?xml version="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-INF/classes/com/xulu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 stubHttpServletRequest 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 stubthis.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

以上就是小编为大家带来的用fileupload组件实现的大文件上传简单实例的全部内容了，希望对大家有所帮助，多多支持武林网~

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