java上传文件
需要两个jar包
commons-fileupload-1.2.2.jar与commons-io-2.4.jar
表单格式必须为
<form action="fileupload.jsp" method="post" enctype="multipart/form-data">
一个接受文件的例子
<%@page import="java.io.File"%> <%@page import="org.apache.commons.fileupload.FileItem"%> <%@page import="org.apache.commons.fileupload.servlet.ServletFileUpload"%> <%@page import="org.apache.commons.fileupload.disk.DiskFileItemFactory"%> <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <base href="<%=basePath%>"> <title>My JSP 'fileupload.jsp' starting page</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"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> <% request.setCharacterEncoding("utf-8"); String uploadpath="d:/upload"; //File folder=new File("upload"); DiskFileItemFactory factory= new DiskFileItemFactory(); factory.setSizeThreshold(30*1024); factory.setRepository(factory.getRepository()); ServletFileUpload upload=new ServletFileUpload(factory); int maxsize=5*1024*1024; List list=upload.parseRequest(request); Iterator iterator=list.iterator(); while(iterator.hasNext()){ FileItem item=(FileItem)iterator.next(); if(!item.isFormField()){ String filePath=item.getName(); if(filePath!=null){ File filename=new File(item.getName()); } if(item.getSize()>maxsize){ out.print("文件太大 ，不得超过5M"); break; } File saveFile=new File(uploadpath,filePath); item.write(saveFile); out.print("文件上传成功 "); } response.sendRedirect("success.jsp"); } %> </body> </html>
禁止上传指定类型文件：
<%@page import="org.apache.commons.io.filefilter.SuffixFileFilter"%> <%@page import="java.io.File"%> <%@page import="org.apache.commons.fileupload.FileItem"%> <%@page import="org.apache.commons.fileupload.servlet.ServletFileUpload"%> <%@page import="org.apache.commons.fileupload.disk.DiskFileItemFactory"%> <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <base href="<%=basePath%>"> <title>My JSP 'fileupload.jsp' starting page</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"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> <% request.setCharacterEncoding("utf-8"); String uploadpath="d:/upload"; //File folder=new File("upload"); DiskFileItemFactory factory= new DiskFileItemFactory(); factory.setSizeThreshold(30*1024); factory.setRepository(factory.getRepository()); ServletFileUpload upload=new ServletFileUpload(factory); int maxsize=5*1024*1024; List list=upload.parseRequest(request); String[] limit = new String[]{".exe", "dat"}; SuffixFileFilter filter = new SuffixFileFilter(limit); Iterator iterator=list.iterator(); while(iterator.hasNext()){ FileItem item=(FileItem)iterator.next(); if(!item.isFormField()){ String filePath=item.getName(); if(filePath!=null){ File filename=new File(item.getName()); } if(item.getSize()>maxsize){ out.print("文件太大 ，不得超过5M"); break; } File saveFile=new File(uploadpath,filePath); boolean flag = filter.accept(saveFile); if(flag){ out.print("error"); break; }else{ item.write(saveFile); out.print("文件上传成功 "); }; } response.sendRedirect("success.jsp"); } %> </body> </html>
对于form表单的属性enctype，通常使用默认值application/x-www-form-urlencoded,这样可以通过request对象的getParameter()方法获取表单元素值，但是在文件域中将表单的enctype属性设置成了multipart/form-data,这样通过getParameter()方法就无法获取了。
下面介绍一个实例
上传页面
<% Date now = new Date(); String time = String.format("%tF", now); %> <form action="fileupload.jsp" method="post" enctype="multipart/form-data"> 选择文档<input type="file" name="file1" size="20"> 上传者<input type="text" name="name" size="20"> 文档名称<input type="text" name="filenames" size="20"> 上传时间<input type="text" name="upTime" value="<%=time %>"> <input type="submit" value="提交"/> </form>
处理页面
<% String name=null, filenames=null, upTime=null,meg=null; request.setCharacterEncoding("utf-8"); String uploadpath = "d:/upload"; DiskFileItemFactory factory = new DiskFileItemFactory(); factory.setSizeThreshold(30*1024); factory.setRepository(factory.getRepository()); ServletFileUpload upload = new ServletFileUpload(factory); int maxsize = 5*1024*1024; List list = upload.parseRequest(request); Iterator iterator = list.iterator(); while(iterator.hasNext()){ FileItem item = (FileItem) iterator.next(); if(!item.isFormField()){ String filePath = item.getName(); if(filePath!=null){ File filename = new File(item.getName()); } if(item.getSize()>maxsize){ meg="too big"; break; } File saveFile = new File(uploadpath, filePath); item.write(saveFile); meg="success"; }else{ String formName = item.getFieldName(); String formcon = item.getString("utf-8"); if(formName.equals("name")){ name = formcon; } else if(formName.equals("filenames")){ filenames = formcon; } else if(formName.equals("upTime")){ upTime = formcon; } } } request.setAttribute("meg", meg); request.setAttribute("name", name); request.setAttribute("filenames", filenames); request.setAttribute("uptime", upTime); request.getRequestDispatcher("success.jsp").forward(request, response); %>
成功页面
<body>
${requestScope.meg }
${requestScope.name }
${requestScope.filenames }
${requestScope.uptime }
</body>
