文件上传与下载简单实例

package com.v512; import java.io.File; import java.io.IOException; import java.io.PrintWriter; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; 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; import org.apache.commons.mail.EmailAttachment; import org.apache.commons.mail.EmailException; import org.apache.commons.mail.MultiPartEmail; public class SendAttachmentMailServlet extends HttpServlet { private static final long serialVersionUID = -1408700020471642036L; private ServletContext sc; private String savePath; File file; private Map<String,String> parameters = new HashMap<String,String>(); 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"); File file = this.doAttachment(request); MultiPartEmail email = new MultiPartEmail(); email.setCharset("UTF-8"); email.setHostName("smtp.sina.com"); email.setAuthentication("web08","web2008"); try { email.addTo(parameters.get("to")); email.setFrom(parameters.get("from")); email.setSubject(parameters.get("title")); email.setMsg(parameters.get("content")); if(file!=null) { EmailAttachment attachment = new EmailAttachment(); attachment.setPath(file.getPath()); attachment.setDisposition(EmailAttachment.ATTACHMENT); attachment.setName(file.getName()); email.attach(attachment); } email.send(); request.setAttribute("upload.message","上传文件成功!"); } catch (EmailException e) { e.printStackTrace(); request.setAttribute("upload.message","上传文件失败!"); } request.getRequestDispatcher("/uploadResult.jsp").forward(request,response); } public File doAttachment(HttpServletRequest request) throws ServletException,IOException { DiskFileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory); try { List list = upload.parseRequest(request); Iterator it = list.iterator(); while(it.hasNext()) { FileItem item = (FileItem)it.next(); if(item.isFormField()) { parameters.put(item.getFieldName(),item.getString("UTF-8")); }else { if(item.getName()!=null&&!item.getName().equals("")) { File tempFile = new File(item.getName()); System.out.println(sc.getRealPath("/")+savePath); file = new File(sc.getRealPath("/")+savePath,tempFile.getName()); item.write(file); } } } }catch (Exception e) { e.printStackTrace(); } return file; } public void init(ServletConfig config) { savePath = config.getInitParameter("savePath"); sc = config.getServletContext(); } }