java中文件上传与下载
1。上传文件流程
先通过用户提交文件，保存文件到服务器端，然后在写入数据库中，每次到下载页面时从数据库中读出文件，生成文件在服务器目录中，以下。。。
文件上传后保存文件到服务器中jsp，
upFile.jsp
<%@ page contentType="text/html; charset=utf-8" language="java" %><%@page import="java.util.List;"%><html><head><title>上传文件</title><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><base target="_self"><link href="Css/style.css" rel="stylesheet"><script type="text/javascript"> function check(){ var file = document.getElementById("file1").value; if(file == ""){ alert('请选择要上传的文件'); return false; }else{ window.returnValue=file; return true; } }</script></head><body><%String files=request.getParameter("files");%><form name="form2" enctype="multipart/form-data" method="post" action="../MissionManage/commonfile.jsp?files=<%=files %>" onsubmit="return check();"><center><table align="center" width="350" height="150" border="0" cellpadding="0" cellspacing="0"><!-- background="images/upFile_bg.gif --> <tr> <td valign="top"><table width="100%" height="145" border="0" cellpadding="0" cellspacing="0"> <tr> <td height="49" colspan="2"> </td> </tr> <tr> <td width="9%" height="53"> </td> <td width="91%"><b>请选择上传的文件：</b><br> <input id="file1" name="file1" type="file" size="35" onkeydown="return false;"> <br> 注：文件大小请控制在10M以内。</td> </tr> <tr> <td colspan="2" align="center"><input name="Submit" type="submit" value="确认"> <input name="Submit2" type="button" onClick="window.close()" value="关闭"></td> </tr> </table></td> </tr></table></center></form></body></html><%@ page language="java" import="java.io.*" pageEncoding="UTF-8"%><%@page import="java.util.*,org.apache.commons.fileupload.FileItem" %><%@page import="java.text.SimpleDateFormat,java.util.Date" %><%@page import="com.PoliceSystem.tools.FileOperate" %><jsp:useBean id="factory" scope="page" /><jsp:useBean id="upload" scope="page" /><%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>上传文件</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"><base target="_self"><!--<link rel="stylesheet" type="text/css" href="styles.css">--><script type="text/javascript" language="javascript"> </script></head><body> <% request.setCharacterEncoding("UTF-8"); String path1 = (String)request.getRealPath("/upload1"); String files=request.getParameter("files"); String[] fileList=files.split(";"); File file = new File(path1); if(!file.exists()){ file.mkdirs(); } factory.setRepository(file); factory.setSizeThreshold(1024*1024); upload.setFileItemFactory(factory); try{ List<FileItem> list= upload.parseRequest(request); for(FileItem item:list){ if(item.isFormField()){ //String value=item.getString("UTF-8"); //session.setAttribute("fileName", value); }else{ String value=item.getName(); int start=value.lastIndexOf("\"); String fileName=value.substring(start+1); if(fileName.length() == 0 || fileName == ""){ out.println("<script>alert('上传失败');window.close();</script>"); }else{ if(item.getSize()>10000000){ out.println("<script>alert('对不起，您上传的文件超过10M,无法完成上传！');window.close();</script>"); }else{ SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss"); Date date =new Date(); String[] f = item.getName().split("\\\"); //System.out.println(f[f.length-1]); String oldFileName = f[f.length-1]; for(int i=0;i<fileList.length;i++){ if(fileList[i].indexOf(oldFileName)!=-1){ out.println("<script>alert('对不起，您上传的文件与现有上传的文件重名，请更换文件名重新上传！');window.returnValue='';window.close();</script>"); } } String fType = FileOperate.getFileType(item.getName());//文件类型 fileName = sdf.format(date)+"."+fType;//新文件名 //System.out.println(item.getName()+"---"+fileName); item.write(new java.io.File(path1,fileName)); //////--1--///// String mailFileNames = new String(); String old = (String)session.getAttribute("fuJianFileNames"); if(old!=null){ mailFileNames = old; } mailFileNames+=oldFileName+"|"+fileName+";"; //System.out.println("mailFileNames="+mailFileNames); session.removeAttribute("fuJianFileNames"); session.setAttribute("fuJianFileNames", mailFileNames); //////--2--///// //String pathName = path1+"\"+fileName; //System.out.println("pathName="+pathName); out.println("<script>window.close();</script>"); } } } } }catch (Exception e) { e.printStackTrace(); out.println("<script>window.close();</script>"); } %></body></html>public boolean insert_annex(String[] str){ boolean b=true; String sql =""; con = db.getConn(); try{ sql="insert into annex (querykey,sfilename,committime,Filetype,filepath,pno,Annex) values (?,?,?,?,?,?,?)"; ps = con.prepareStatement(sql); for(int i=0;i<str.length-1;i++){ ps.setString(i+1, str[i]); } File file = new File(str[6]);//附件 InputStream iso = new FileInputStream(file); ps.setBinaryStream(7, iso, iso.available()); ps.execute(); iso.close(); System.out.println("删除临时文件：" + file.delete());// 删除tmp文件 }catch(Exception e){ b=false; e.printStackTrace(); }finally{ this.close(); } return b;}public boolean addTempFile_annex(String querykey,HttpServletRequest request){ boolean b=true; con = db.getConn(); InputStream in = null; OutputStream out= null; String path1 = (String)request.getRealPath("/upload1");//文件下载临时目录 try{ String sql="select filePath,annex from annex where querykey='"+querykey+"'"; //String sql_1="select annex from annex where querykey='"+querykey+"'"; ps = con.prepareStatement(sql); rs=ps.executeQuery(); while(rs.next()){ File f = new File(path1+rs.getString("filepath")); in=rs.getBinaryStream("annex"); out = new FileOutputStream(f); int len = 10 * 100 * 100; //定义字符数组长度 byte[] P_Buf=new byte[len]; int j; while((j=in.read(P_Buf))!=-1){ out.write(P_Buf, 0, j); } } in.close(); out.flush(); //强制清出缓冲区 out.close(); }catch(Exception e){ b=false; e.printStackTrace(); }finally{ this.close(); } return b;}package com.PoliceSystem.action.mail;import java.io.File;import java.io.FileInputStream;import java.io.InputStream;import java.io.OutputStream;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.struts2.ServletActionContext;import com.opensymphony.xwork2.ActionSupport;public class downLoadFile extends ActionSupport{private static final long serialVersionUID = -2207648627734251737L;public String execute() throws Exception{ HttpServletRequest request = ServletActionContext.getRequest(); HttpServletResponse response = ServletActionContext.getResponse(); String fileminitype = request.getParameter("fileType"); String filename1 = new String(request.getParameter("fileName1").getBytes("ISO8859-1"),"UTF-8"); String filename2 = new String(request.getParameter("fileName2").getBytes("ISO8859-1"),"UTF-8"); String filepath = request.getRealPath("/upload1"); File f = new File(filepath+"\"+filename2); Long filelength = f.length(); int cacheTime = 10; response.setContentType(fileminitype); response.setHeader("Location",filename1); response.setHeader("Cache-Control", "max-age=" + cacheTime); response.setContentType("application/octet-stream"); byte[] b = filename1.getBytes("GBK"); filename1 = new String(b,"8859_1"); response.setHeader("Content-Disposition", "attachment;filename=" + filename1); response.setContentLength(filelength.intValue()); OutputStream outputStream = response.getOutputStream(); InputStream inputStream = new FileInputStream(f); byte[] buffer = new byte[1024]; int i = -1; while ((i = inputStream.read(buffer)) != -1) { outputStream.write(buffer, 0, i); } outputStream.flush(); outputStream.close(); inputStream.close(); return null ; }}