Java文件上传与下载

来源：互联网发布：加工中心编程实例编辑：程序博客网时间：2024/05/02 17:34

需要：commons-io.jar 和 commons-fileupload.jar

upload.jsp

<%@ page language="java" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>  <script type="text/javascript">  //全局变量  var time = 0;  function addLine(addButton){  //创建内部div对象  var divElement = document.createElement("div");  //创建input对象[file类型]  var inputElement1 = document.createElement("input");  inputElement1.type="file";  inputElement1.name="upfile";  //创建input对象[button类型]  var inputElement2 = document.createElement("input");  inputElement2.type="button";  inputElement2.value="删除";  //对删除按钮添加事件监听  inputElement2.onclick=function(){  //取得该按钮所在行的直接父元素  var divElement = this.parentNode.parentNode;  //通过父元素删除直接子元素  divElement.removeChild(this.parentNode);  time--;  if(time < 5){  //按钮生效  addButton.disabled=false;  //addButton.style.visibility="visible";  }  }  //依次将file类型和button类型的input对象加入到内部div对象中  divElement.appendChild(inputElement1);  divElement.appendChild(inputElement2);  //再次内部div对象加入到外部div对象  var outDivElement = document.getElementById("outDiv");  outDivElement.appendChild(divElement);  time++;  if(time == 5){  //将按钮失效  addButton.disabled=true;  //addButton.style.visibility="hidden";  }  }  </script>  </head>  <body>  <form   action="${pageContext.request.contextPath}/UploadServlet"   method="POST"  enctype="multipart/form-data">  <table border="1" align="center">  <caption>文件上传</caption>  <tr>  <th>上传用户</th>  <td><input type="text" name="username"/></td>  </tr>  <tr>  <th></th>  <td>  <div id="outDiv">  <%--  <div><input type="file" name="upfile"/><input type="button" value="删除"/>    </div>  --%>  </div>  </td>  </tr>  <tr>  <th></th>  <td>  <input   type="button"   value="添加上传文件"  onclick="addLine(this)"  />  </td>  </tr>  <tr>  <td colspan="2" align="center">  <input type="submit" value="上传"/>  <a href="${pageContext.request.contextPath}/ListFileServlet">  显示下载文件  </a>  </td>  </tr>  </table>  </form>  </body></html>

UploadServlet.java

package cn.itcast.web.servlet.upload;import java.io.File;import java.io.IOException;import java.io.InputStream;import java.util.List;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 cn.itcast.web.servlet.util.UploadUtil;public class UploadServlet3 extends HttpServlet {public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {//创建上传文件工厂DiskFileItemFactory factory = new DiskFileItemFactory();//设置内存中缓存区的大小，默认10Kfactory.setSizeThreshold(100*1024);//设置上传文件临时存放的目录String tempPath = this.getServletContext().getRealPath(UploadUtil.tempPath);factory.setRepository(new File(tempPath));//创建上传文件对象[核心]ServletFileUpload upload = new ServletFileUpload(factory);//设置上传文件的中文编码方式upload.setHeaderEncoding("UTF-8");//客户端上传文件是否使用MIME协议，boolean flag = upload.isMultipartContent(request);if(!flag){//不是以MIME协议上传文件throw new ServletException();}else{/*是以MIME协议上传的文件，解析request中的所有上传内容 *每个内容封装成一个对象FileItem， *FileItem代表普通字段和上传字段二类 */try {List<FileItem> fileItemList  = upload.parseRequest(request);for(FileItem fileItem : fileItemList){if(fileItem.isFormField()){//必定是普通字段String fieldName = fileItem.getFieldName();String fieldValue = fileItem.getString("UTF-8");System.out.println(fieldName+":"+fieldValue);}else {//必定是上传字段String realFileName = fileItem.getName();//取得真实文件名realFileName = UploadUtil.getRealFileName(realFileName);//通过真实文件名换算出唯一个文件名String uuidFileName = UploadUtil.makeUuidFileName(realFileName);//通过位运算换算出upload目录下的子目录String uploadPath = this.getServletContext().getRealPath(UploadUtil.uploadPath);String uuidFilePath = UploadUtil.makeUuidFilePath(uploadPath,uuidFileName);//取得文件输入流InputStream is = fileItem.getInputStream();//取得文件输出流UploadUtil.doSave(is,uuidFileName,uuidFilePath);//将上传文件产生的临时文件删除fileItem.delete();request.setAttribute("message","上传文件成功");request.getRequestDispatcher("/WEB-INF/message.jsp").forward(request,response);}}} catch (Exception e) {e.printStackTrace();request.setAttribute("message","上传文件失败");request.getRequestDispatcher("/WEB-INF/message.jsp").forward(request,response);}}}}

list.jsp

<%@ page language="java" pageEncoding="UTF-8"%><%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <body>  <table border="1" align="center">  <caption>下载文件列表</caption>  <tr>  <th>文件名</th>  <th>操作</th>  </tr>  <c:forEach var="entry" items="${requestScope.map}">  <tr>  <td>${entry.value}</td>  <td>  <c:url var="myURL" value="/DownloadServlet">  <c:param name="uuidFileName" value="${entry.key}"/>  </c:url>  <a  href="${myURL}"   style="text-decoration:none">  下载  </a>  </td>  </tr>  </c:forEach>  </table>  </body></html>

DownloadServlet.java

package cn.itcast.web.servlet.download;import java.io.FileInputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import java.net.URLEncoder;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import cn.itcast.web.servlet.util.UploadUtil;//下载文件到本地public class DownloadServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {String uuidFileName = request.getParameter("uuidFileName");byte[] buf = uuidFileName.getBytes("ISO8859-1");uuidFileName = new String(buf,"UTF-8");int index = uuidFileName.lastIndexOf("_");String realFileName = uuidFileName.substring(index+1);response.setHeader("content-disposition","attachment;filename="+URLEncoder.encode(realFileName,"UTF-8"));String uploadPath = this.getServletContext().getRealPath(UploadUtil.uploadPath);String uuidFilePath = UploadUtil.makeUuidFilePath(uploadPath,uuidFileName);InputStream is = new FileInputStream(uuidFilePath+"/"+uuidFileName);//模式：/WEB-INF/upload/12/4/43213_cc.jpgOutputStream os = response.getOutputStream(); buf = new byte[1024];int len = 0;while((len=is.read(buf))>0){os.write(buf,0,len);}is.close();os.close();}}

0 0