說到文件上傳我們要做到：
1.引入兩個包：commons-fileupload-1.2.1.jar和commons-io-1.3.2.jar
2.將form改為上傳文件模式：enctype="multipart/form-data"
3.開始編寫相關代碼
這里會用到幾個關鍵的類：磁盤文件工廠DiskFileItemFactory ； 創(chuàng)建servlet文件上傳類：ServletFileUpload
還有幾個重要的方法：DiskFileItemFactory類用于將以臨時文件形式保存在磁盤上的存放目錄的方法setRepository；
ServletFileUpload類得到表單中所有的數(shù)據(jù)，得到form表單中所有的元素方法：parseRequest
下面看具體代碼：
說明以這種方式上傳文件是保存在服務器端的！
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import java.io.File;import java.io.IOException;import java.io.PrintWriter;import java.util.ArrayList;import java.util.List;import java.util.UUID; 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.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;import org.apache.commons.io.FileUtils; public class UploadServlet extends HttpServlet { /** * Constructor of the object. */ public UploadServlet() { super(); } /** * Destruction of the servlet. <br> */ public void destroy() { super.destroy(); // Just puts "destroy" string in log // Put your code here } /** * The doGet method of the servlet. <br> * * This method is called when a form has its tag value method equals to get. * * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */ public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } /** * The doPost method of the servlet. <br> * * This method is called when a form has its tag value method equals to post. * * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */ public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); DiskFileItemFactory sf= new DiskFileItemFactory();//實例化磁盤被文件列表工廠 String path = request.getRealPath("/upload");//得到上傳文件的存放目錄 sf.setRepository(new File(path));//設置文件存放目錄 sf.setSizeThreshold(1024*1024);//設置文件上傳小于1M放在內(nèi)存中 String rename = "";//文件新生成的文件名 String fileName = "";//文件原名稱 String name = "";//普通field字段 //從工廠得到servletupload文件上傳類 ServletFileUpload sfu = new ServletFileUpload(sf); try { List<FileItem> lst = sfu.parseRequest(request);//得到request中所有的元素 for (FileItem fileItem : lst) { if(fileItem.isFormField()){ if("name".equals(fileItem.getFieldName())){ name = fileItem.getString("UTF-8"); } }else{ //獲得文件名稱 fileName = fileItem.getName(); fileName = fileName.substring(fileName.lastIndexOf("\\")+1); String houzhui = fileName.substring(fileName.lastIndexOf(".")); rename = UUID.randomUUID()+houzhui; fileItem.write(new File(path, rename)); } } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } System.out.println("普通字段"+name); System.out.println("文件名稱"+fileName); System.out.println("修改后生成的文件名稱"+rename); response.sendRedirect("ok.jsp"); out.flush(); out.close(); } /** * Initialization of the servlet. <br> * * @throws ServletException if an error occurs */ public void init() throws ServletException { // Put your code here } } |
index.jsp頁面：
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<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html> <head> <title>文件測試界面</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> </head> <body> <div align="center"> <form action="UploadServlet" enctype="multipart/form-data" method="post"> 名稱：<input name="name" /> <br> 圖片：<input name="img" type="file"/><br> <input type="submit" value="提交" /> <input type="reset" value="重置" /> </form> </div> </body></html> |
ok.jsp頁面：
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<body> <h1 align="center">上傳文件成功!</h1> </body> |
實現(xiàn)效果就不截圖了，有需要自己那過去用！
以上這篇java文件上傳Demo(必看篇)就是小編分享給大家的全部內(nèi)容了，希望能給大家一個參考，也希望大家多多支持服務器之家。
