二丶上传的的servlet
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package com.test.action; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.List; 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.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; @WebServlet ( "/upload" ) public class FileUpLoadAction extends HttpServlet { private static final long serialVersionUID = 1L; protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 设置编码 request.setCharacterEncoding( "utf-8" ); //对提交的数据进行处理,保存上传文件 boolean success = processUpload(request); if (success){ //获取表单text控件的值 String account = request.getAttribute( "account" ).toString(); System.out.println(account); //获取文件上传的原始名称 String fileName = request.getAttribute( "upfile" ).toString(); System.out.println(fileName); //获取文件上传后,服务器上保存的名字 String fileNameServer = request.getAttribute( "upfileServer" ).toString(); System.out.println(fileNameServer); request.setAttribute( "upfile" , fileNameServer); request.setAttribute( "message" , "上传成功" ); } request.getRequestDispatcher( "/upload.jsp" ).forward(request, response); } private boolean processUpload(HttpServletRequest request) { boolean success = true ; String message = null ; // 获取文件需要上传到的路径 String path = request.getServletContext().getRealPath( "/upload" ); System.out.println(path); // 如果此文件夹不存在,则构造此文件夹 File f = new File(path); if (!f.exists()) { f.mkdir(); } // 构造出文件工厂,用于存放JSP页面中传递过来的文件 DiskFileItemFactory factory = new DiskFileItemFactory(); // 设置上传文件的保存路径 factory.setRepository(f); // 设置缓存大小,如果文件大于缓存大小时,则先把文件放到缓存中 factory.setSizeThreshold( 1 * 1024 * 1024 ); ServletFileUpload upload = new ServletFileUpload(factory); // 设置可以上传文件大小的上界20MB upload.setSizeMax( 20 * 1024 * 1024 ); try { // 可以上传多个文件 List<FileItem> list = (List<FileItem>) upload.parseRequest(request); for (FileItem item : list) { // 获取表单的属性名字 String name = item.getFieldName(); if (item.isFormField()) { String value = item.getString(); //解决乱码问题 value = new String(value.getBytes( "iso-8859-1" ), "utf-8" ); request.setAttribute(name, value); } else { // 获得文件类型 String contentType = item.getContentType(); // 获得文件大小 long fileSize = item.getSize(); // 获取路径名 String value = item.getName(); // 索引到最后一个反斜杠 int start = value.lastIndexOf( "\\" ); // 截取 上传文件的 字符串名字,加1是 去掉反斜杠, String filename = value.substring(start + 1 ); if (filename != null && !filename.trim().equals( "" )) { // 如果上传的文件不是图片,那么不上传 String allImgExt = ".jpg|.jpeg|.gif|.bmp|.png|" ; String extName = filename.substring(filename.indexOf( "." ), filename.length()); if (allImgExt.indexOf(extName + "|" ) == - 1 ) { message = "该文件类型不允许上传。请上传 " + allImgExt + " 类型的文件,当前文件类型为" + extName; success = false ; break ; } request.setAttribute(name, filename); // 随机数产生名称 String newName = System.currentTimeMillis() + extName; request.setAttribute(name + "Server" , newName); // 将文件保存到服务器中 InputStream in = item.getInputStream(); // 原文件名 // OutputStream out = new FileOutputStream(new File(path, filename)); // 随机数文件名 OutputStream out = new FileOutputStream( new File(path, newName)); int length = 0 ; byte [] buf = new byte [ 1024 ]; while ((length = in.read(buf)) != - 1 ) { out.write(buf, 0 , length); } in.close(); out.close(); } } } } catch (FileUploadException e) { message = "文件的内容过大,请上传小于20MB的文件" ; success = false ; e.printStackTrace(); } catch (IOException e) { success = false ; e.printStackTrace(); } request.setAttribute( "message" , message); return success; } } |
三丶下载的servlet
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package com.test.action; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.OutputStream; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; @WebServlet ( "/download" ) public class FileDownloadAction extends HttpServlet { private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String id = request.getParameter( "id" ); // 根据主键读取文件的真实名字 + 服务器上的名字 processDownload( "1444442288605.png" , "腾讯.png" , request, response); } private boolean processDownload(String fileName, String saveName, HttpServletRequest request, HttpServletResponse response) { boolean success = true ; // 获取文件下载所在的路径 String path = request.getServletContext().getRealPath( "/upload" ); File fileLoad = new File(path, fileName); // 下载文件 long fileLength = fileLoad.length(); // 文件大小 byte [] buffer = new byte [ 1024 ]; // 缓冲字节数组 try { response.reset(); response.setHeader( "Content-disposition" , "attachment;filename=\"" + new String(saveName.getBytes( "gb2312" ), "ISO-8859-1" ) + "\"" ); response.setContentType( "application/octet-stream" ); response.setHeader( "Content_Length" , String.valueOf(fileLength)); OutputStream os = response.getOutputStream(); FileInputStream in = new FileInputStream(fileLoad); int hasRead = 0 ; while ((hasRead = in.read(buffer)) != - 1 ) { os.write(buffer, 0 , hasRead); } os.flush(); os.close(); in.close(); } catch (IOException e) { success = false ; e.printStackTrace(); } return success; } } |
以上所述是小编给大家介绍的JavaWeb中上传和下载文件实例代码,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对服务器之家网站的支持!
原文链接:http://blog.csdn.net/haitao0823/article/details/73549110