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JavaWeb之文件上传

發布時間：2025/5/22 java 36 豆豆

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1.上傳組件

①Apache的Commons FileUpload

②JavaZoom的UploadBean

③JspSmartUpload

2.下載Commons的FileUpload組件

地址:http://commons.apache.org/fileupload/

同時還要下載Commons的IO組件

地址:http://commons.apache.org/io/

3.使用實例

步驟一：創建文件上傳的頁面：fileUpload.jsp

注意表單的 enctype 屬性，這個設置很重要，詳情請見：http://www.cnblogs.com/yinger/archive/2011/09/11/2173689.html

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html><head><title>文件上傳</title></head><body><form action="<%=request.getContextPath() %>/servlet/FileUploadServlet" method="post" enctype="multipart/form-data" >上傳人名:<input type="text" name="name" /><br/> 上傳文件:<input type="file" name="file" /><br/><input type="submit" name="submit" value="提交" /></form></body> </html>

步驟二：創建處理文件上傳的servlet：fileUploadServlet

package com.yinger.servlet;import java.io.File; import java.io.IOException; import java.util.Iterator; import java.util.List;import javax.servlet.ServletConfig; import javax.servlet.ServletContext; 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.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload;public class FileUploadServlet extends HttpServlet {private ServletContext sc;private String savePath;private static final long serialVersionUID = 151650843430214502L;public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {request.setCharacterEncoding("UTF-8");DiskFileItemFactory factory = new DiskFileItemFactory();ServletFileUpload servletFileUpload = new ServletFileUpload(factory);//通過工廠生成一個處理文件上傳的servlet對象try {List items = servletFileUpload.parseRequest(request);//解析requestIterator iterator = items.iterator();while (iterator.hasNext()) {FileItem item = (FileItem) iterator.next();if(item.isFormField()){//表單的參數字段System.out.println("表單的參數名稱："+item.getFieldName()+",表單的參數值："+item.getString("UTF-8"));}else {if(item.getName()!=null && !item.getName().equals("")){//一個上傳的文件System.out.println("文件的名稱："+item.getName());System.out.println("文件的大小："+item.getSize());System.out.println("文件的類型："+item.getContentType());File tempFile = new File(item.getName());//getName得到的文件名稱包含了它在客戶端的路徑File file = new File(sc.getRealPath("/")+savePath,tempFile.getName());item.write(file);//將上傳的文件寫入到file中request.setAttribute("message", "上傳文件成功！");}else{request.setAttribute("message", "沒有選擇上傳文件！");}}}} catch (Exception e) {e.printStackTrace();request.setAttribute("message", "上傳文件失敗！");}request.getRequestDispatcher("/fileUploadResult.jsp").forward(request, response);//轉向，輸出結果}@Overridepublic void init(ServletConfig config) throws ServletException {savePath = config.getInitParameter("savePath");sc = config.getServletContext(); }}

步驟三：修改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" version="2.5"><display-name></display-name><servlet><description>This is the description of my J2EE component</description><display-name>This is the display name of my J2EE component</display-name><servlet-name>FileUploadServlet</servlet-name><servlet-class>com.yinger.servlet.FileUploadServlet</servlet-class><init-param> <param-name>savePath</param-name><param-value>uploads</param-value></init-param></servlet><servlet-mapping><servlet-name>FileUploadServlet</servlet-name><url-pattern>/servlet/FileUploadServlet</url-pattern></servlet-mapping><welcome-file-list><welcome-file>index.jsp</welcome-file></welcome-file-list> </web-app>

同時在項目的根目錄下創建文件夾 uploads （可以就在WebRoot中創建）

步驟四：創建顯示上傳結果的頁面：fileUploadResult.jsp

<%@ page language="java" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html><head><title>文件上傳</title></head><body><p>${requestScope['message'] }<br/></p></body> </html>

效果展示

總結

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