Java Servlet简单实例,文件上传下载demo
Java Servlet简单实例,文件上传下载demo
项目结构
src com servletdemo DownloadServlet.java ShowServlet.java UploadServlet.java WebContent jsp servlet download.html fileupload.jsp input.jsp WEB-INF lib commons-fileupload-1.3.1.jar commons-io-2.4.jar
1.简单实例
ShowServlet.java
package com.servletdemo; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * Servlet implementation class ShowServlet */ @WebServlet("/ShowServlet") public class ShowServlet extends HttpServlet { private static final long serialVersionUID = 1L; PrintWriter pw=null; /** * @see HttpServlet#HttpServlet() */ public ShowServlet() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub this.doPost(request, response); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub request.setCharacterEncoding("gb2312"); response.setContentType("text/html;charset=gb2312"); pw=response.getWriter(); String name=request.getParameter("username"); String password=request.getParameter("password"); pw.println("user name:" + name); pw.println("<br>"); pw.println("user password:" + password); } }
input.jsp
1 <%@ page language="java" contentType="text/html; charset=ISO-8859-1" 2 pageEncoding="ISO-8859-1"%> 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 4 <html> 5 <head> 6 <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 7 <title>servlet demo</title> 8 </head> 9 <body> 10 <form action="<%=request.getContextPath()%>/ShowServlet"> 11 <table> 12 <tr> 13 <td>name</td> 14 <td><input type="text" name="username"></td> 15 </tr> 16 <tr> 17 <td>password</td> 18 <td><input type="text" name="password"></td> 19 </tr> 20 <tr> 21 <td><input type="submit" value="login"></td> 22 <td><input type="reset" value="cancel"></td> 23 </tr> 24 </table> 25 </form> 26 </body> 27 </html>
2.文件上传实例
UploadServlet.java
package com.servletdemo; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.PrintWriter; import java.text.DateFormat; import java.util.Date; import java.util.List; import java.util.UUID; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; 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.ProgressListener; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; /** * Servlet implementation class UploadServlet */ @WebServlet("/servlet/UploadServlet") public class UploadServlet extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public UploadServlet() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub //设置编码 request.setCharacterEncoding("UTF-8"); response.setContentType("text/html;charset=UTF-8"); PrintWriter pw = response.getWriter(); try { //设置系统环境 DiskFileItemFactory factory = new DiskFileItemFactory(); //文件存储的路径 String storePath = getServletContext().getRealPath("/WEB-INF/files"); //判断传输方式 form enctype=multipart/form-data boolean isMultipart = ServletFileUpload.isMultipartContent(request); if(!isMultipart) { pw.write("传输方式有错误！"); return; } ServletFileUpload upload = new ServletFileUpload(factory); upload.setFileSizeMax(4*1024*1024);//设置单个文件大小不能超过4M upload.setSizeMax(4*1024*1024);//设置总文件上传大小不能超过6M //监听上传进度 upload.setProgressListener(new ProgressListener() { //pBytesRead：当前以读取到的字节数 //pContentLength：文件的长度 //pItems:第几项 public void update(long pBytesRead, long pContentLength, int pItems) { System.out.println("已读去文件字节 :"+pBytesRead+" 文件总长度："+pContentLength+" 第"+pItems+"项"); } }); //解析 List<FileItem> items = upload.parseRequest(request); for(FileItem item: items) { if(item.isFormField())//普通字段，表单提交过来的 { String name = item.getFieldName(); String value = item.getString("UTF-8"); System.out.println(name+"=="+value); }else { // String mimeType = item.getContentType(); 获取上传文件类型 // if(mimeType.startsWith("image")){ InputStream in =item.getInputStream(); String fileName = item.getName(); if(fileName==null || "".equals(fileName.trim())) { continue; } fileName = fileName.substring(fileName.lastIndexOf("\\")+1); fileName = UUID.randomUUID()+"_"+fileName; //按日期来建文件夹 String newStorePath = makeStorePath(storePath); String storeFile = newStorePath+"\\"+fileName; OutputStream out = new FileOutputStream(storeFile); byte[] b = new byte[1024]; int len = -1; while((len = in.read(b))!=-1) { out.write(b,0,len); } in.close(); out.close(); item.delete();//删除临时文件 } } // } }catch(org.apache.commons.fileupload.FileUploadBase.FileSizeLimitExceededException e){ //单个文件超出异常 pw.write("单个文件不能超过4M"); }catch(org.apache.commons.fileupload.FileUploadBase.SizeLimitExceededException e){ //总文件超出异常 pw.write("总文件不能超过6M"); }catch (FileUploadException e) { e.printStackTrace(); } } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } private String makeStorePath(String storePath) { Date date = new Date(); DateFormat df = DateFormat.getDateInstance(DateFormat.MEDIUM); String s = df.format(date); String path = storePath+"\\"+s; File file = new File(path); if(!file.exists()) { file.mkdirs();//创建多级目录，mkdir只创建一级目录 } return path; } private String makeStorePath2(String storePath, String fileName) { int hashCode = fileName.hashCode(); int dir1 = hashCode & 0xf;// 0000~1111：整数0~15共16个 int dir2 = (hashCode & 0xf0) >> 4;// 0000~1111：整数0~15共16个 String path = storePath + "\\" + dir1 + "\\" + dir2; // WEB-INF/files/1/12 File file = new File(path); if (!file.exists()) file.mkdirs(); return path; } }
fileupload.jsp
1 <%@ page language="java" contentType="text/html; charset=ISO-8859-1" 2 pageEncoding="ISO-8859-1"%> 3 4 <% 5 String path = request.getContextPath(); 6 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; 7 %> 8 9 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 10 <html> 11 <head> 12 <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 13 <title>Upload File Demo</title> 14 </head> 15 <body> 16 <form action="${pageContext.request.contextPath}/servlet/UploadServlet" method="post" enctype="multipart/form-data"> 17 user name<input type="text" name="username"/> <br/> 18 <input type="file" name="f1"/><br/> 19 <input type="file" name="f2"/><br/> 20 <input type="submit" value="save"/> 21 </form> 22 </body> 23 </html>
3.文件下载实例
DownloadServlet.java
package com.servletdemo; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStream; import java.io.PrintWriter; import java.net.URLEncoder; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.ServletResponse; /** * Servlet implementation class DownloadServlet */ @WebServlet("/DownloadServlet") public class DownloadServlet extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public DownloadServlet() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub download1(response); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } public void download1(HttpServletResponse response) throws IOException{ //获取所要下载文件的路径 String path = this.getServletContext().getRealPath("/files/web配置.xml"); String realPath = path.substring(path.lastIndexOf("\\")+1); //告诉浏览器是以下载的方法获取到资源 //告诉浏览器以此种编码来解析URLEncoder.encode(realPath, "utf-8")) response.setHeader("content-disposition","attachment; filename="+URLEncoder.encode(realPath, "utf-8")); //获取到所下载的资源 FileInputStream fis = new FileInputStream(path); int len = 0; byte [] buf = new byte[1024]; while((len=fis.read(buf))!=-1){ response.getOutputStream().write(buf,0,len); } } }
download.html
1 <!DOCTYPE html> 2 <html> 3 <head> 4 <meta charset="ISO-8859-1"> 5 <title>Download Demo</title> 6 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> 7 <meta http-equiv="description" content="this is my page"> 8 <meta http-equiv="content-type" content="text/html; charset=UTF-8"> 9 </head> 10 <body> 11 <a href = "/JavabeanDemo/DownloadServlet">download</a> 12 </body> 13 </html>
