本人闲来无事,写了个servlet,实现上传下载功能。启动服务后,可以在一个局域网内当一个小小的文件服务器。
一、准备工作
下载两个jar包:
commons-fileupload-1.3.1.jar
commons-io-2.2.jar
二、创建一个web工程
我的工程名叫:z-upload
三、配置web.xml
<?xml version=\"1.0\" encoding=\"UTF-8\"?> <web-app xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns=\"http://java.sun.com/xml/ns/javaee\" xsi:schemaLocation=\"http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd\" id=\"WebApp_ID\" version=\"3.0\"> <display-name>z-upload</display-name> <servlet> <servlet-name>UploadService</servlet-name> <servlet-class>com.syz.servlet.UploadService</servlet-class> </servlet> <servlet-mapping> <servlet-name>UploadService</servlet-name> <url-pattern>/*</url-pattern> </servlet-mapping> </web-app>
从以上配置可以看出,我的servlet类是UploadService,匹配的url是/*,意思是匹配所有访问url。
四、写servlet类
package com.syz.servlet; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.PrintWriter; import java.text.SimpleDateFormat; import java.util.Date; import java.util.Iterator; import java.util.List; 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.FileUploadException; import org.apache.commons.fileupload.ProgressListener; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; public class UploadService extends HttpServlet { public static final String LIST = \"/list\"; public static final String FORM = \"/form\"; public static final String HANDLE = \"/handle\"; public static final String DOWNLOAD = \"/download\"; public static final String DELETE = \"/delete\"; public static final String UPLOAD_DIR = \"/upload\"; private static final long serialVersionUID = 2170797039752860765L; public void execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { System.out.println(\"execute...\"); System.out.println(\"------------begin---------------\"); req.setCharacterEncoding(\"UTF-8\"); String host = req.getRemoteHost(); System.out.println(\"host:\" + host); String uri = req.getRequestURI(); System.out.println(\"uri:\" + uri); ServletContext servletContext = this.getServletConfig() .getServletContext(); // 上传文件的基本路径 String basePath = servletContext.getRealPath(UPLOAD_DIR); // 上下文路径 String contextPath = servletContext.getContextPath(); System.out.println(\"contextPath:\" + contextPath); // 截取上下文之后的路径 String action = uri.substring(contextPath.length()); System.out.println(\"action:\" + action); // 依据action不同进行不同的处理 if (action.equals(FORM)) { form(contextPath, resp); } else if (action.equals(HANDLE)) { boolean isMultipart = ServletFileUpload.isMultipartContent(req); System.out.println(\"isMultipart:\" + isMultipart); if (!isMultipart) { return; } DiskFileItemFactory factory = new DiskFileItemFactory(); File repository = (File) servletContext .getAttribute(ServletContext.TEMPDIR); System.out.println(\"repository:\" + repository.getAbsolutePath()); System.out.println(\"basePath:\" + basePath); factory.setSizeThreshold(1024 * 100); factory.setRepository(repository); ServletFileUpload upload = new ServletFileUpload(factory); // 创建监听 ProgressListener progressListener = new ProgressListener() { public void update(long pBytesRead, long pContentLength, int pItems) { System.out.println(\"当前文件大小:\" + pContentLength + \"\\t已经处理:\" + pBytesRead); } }; upload.setProgressListener(progressListener); List<FileItem> items = null; try { items = upload.parseRequest(req); System.out.println(\"items size:\" + items.size()); Iterator<FileItem> ite = items.iterator(); while(ite.hasNext()){ FileItem item = ite.next(); if(item.isFormField()){ // handle FormField }else{ // handle file String fieldName = item.getFieldName(); String fileName = item.getName(); fileName = fileName.substring( fileName.lastIndexOf(File.separator) + 1); String contentType = item.getContentType(); boolean isInMemory = item.isInMemory(); long sizeInBytes = item.getSize(); System.out.println(fieldName + \"\\t\" + fileName + \"\\t\" + contentType + \"\\t\" + isInMemory + \"\\t\" + sizeInBytes); File file = new File( basePath + \"/\" + fileName + \"_\" + getSuffix()); // item.write(file); InputStream in = item.getInputStream(); OutputStream out = new FileOutputStream(file); byte[] b = new byte[1024]; int n = 0; while ((n = in.read(b)) != -1) { out.write(b, 0, n); } out.flush(); in.close(); out.close(); } } // 处理完后重定向到文件列表页面 String href1 = contextPath + LIST; resp.sendRedirect(href1); } catch (FileUploadException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } } else if (action.equals(LIST)) { list(contextPath, basePath, resp); } else if (action.equals(DOWNLOAD)) { String id = req.getParameter(\"id\"); System.out.println(\"id:\" + id); if (id == null) { return; } File file = new File(basePath); File[] list = file.listFiles(); int len = list.length; boolean flag = false; for (int i = 0; i < len; i++) { File f = list[i]; String fn = f.getName(); if (f.isFile() && fn.lastIndexOf(\"_\") > -1) { String fid = fn.substring(fn.lastIndexOf(\"_\")); if (id.equals(fid)) { download(f, resp); flag = true; break; } } } if (!flag) { notfound(contextPath, resp); } } else if (action.equals(DELETE)) { String id = req.getParameter(\"id\"); System.out.println(\"id:\" + id); if (id == null) { return; } File file = new File(basePath); File[] list = file.listFiles(); int len = list.length; boolean flag = false; for (int i = 0; i < len; i++) { File f = list[i]; String fn = f.getName(); if (f.isFile() && fn.lastIndexOf(\"_\") > -1) { String fid = fn.substring(fn.lastIndexOf(\"_\")); if (id.equals(fid)) { f.delete(); flag = true; break; } } } if (flag) { // 处理完后重定向到文件列表页面 String href1 = contextPath + LIST; resp.sendRedirect(href1); } else { notfound(contextPath, resp); } } else { show404(contextPath, resp); } System.out.println(\"------------end---------------\"); } private void show404(String contextPath, HttpServletResponse resp) throws IOException { resp.setContentType(\"text/html;charset=utf-8\"); PrintWriter out = resp.getWriter(); String href1 = contextPath + LIST; out.write(\"<html>\"); out.write(\"<head><title>404</title></thead>\"); out.write(\"<body>\"); out.write(\"<b>您所访问的页面不存在!<a href=\'\" + href1 + \"\'>点击</a>返回文件列表</b>\"); out.write(\"</body>\"); out.write(\"</html>\"); out.close(); } private void form(String contextPath, HttpServletResponse resp) throws IOException { resp.setContentType(\"text/html;charset=utf-8\"); PrintWriter out = resp.getWriter(); String href1 = contextPath + LIST; out.write(\"<html>\"); out.write(\"<head><title>form</title></thead>\"); out.write(\"<body>\"); out.write(\"<b><a href=\'\" + href1 + \"\'>点击</a>返回文件列表</b>\"); out.write( \"<form action=\'handle\' method=\'post\' enctype=\'multipart/form-data\' style=\'margin-top:20px;\'>\"); out.write(\"<input name=\'file\' type=\'file\'/><br>\"); out.write(\"<input type=\'submit\' value=\'上传\'/><br>\"); out.write(\"</form>\"); out.write(\"</body>\"); out.write(\"</html>\"); out.close(); } private void notfound(String contextPath, HttpServletResponse resp) throws IOException { resp.setContentType(\"text/html;charset=utf-8\"); PrintWriter out = resp.getWriter(); String href1 = contextPath + LIST; out.write(\"<html><body><b>操作失败!文件不存在或文件已经被删除!<a href=\'\" + href1 + \"\'>点击</a>返回文件列表</b></body></html>\"); out.close(); } private void download(File f, HttpServletResponse resp) throws IOException { String fn = f.getName(); String fileName = fn.substring(0, fn.lastIndexOf(\"_\")); System.out.println(\"fileName:\" + fileName); resp.reset(); resp.setContentType(\"application/octet-stream\"); String encodingFilename = new String(fileName.getBytes(\"GBK\"), \"ISO8859-1\"); System.out.println(\"encodingFilename:\" + encodingFilename); resp.setHeader(\"content-disposition\", \"attachment;filename=\" + encodingFilename); InputStream in = new FileInputStream(f); OutputStream out = resp.getOutputStream(); byte[] b = new byte[1024]; int n = 0; while ((n = in.read(b)) != -1) { out.write(b, 0, n); } out.flush(); in.close(); out.close(); } private void list(String contextPath, String basePath, HttpServletResponse resp) throws IOException { String href_u = contextPath + FORM; resp.setContentType(\"text/html;charset=utf-8\"); PrintWriter out = resp.getWriter(); out.write(\"<html>\"); out.write(\"<head><title>list</title></thead>\"); out.write(\"<body>\"); out.write(\"<b>我要<a href=\'\" + href_u + \"\'>上传</a></b><br>\"); out.write( \"<table border=\'1\' style=\'border-collapse:collapse;width:100%;margin-top:20px;\'>\"); out.write(\"<thead>\"); out.write(\"<tr>\"); out.write(\"<th>序号</th><th>文件名</th><th>操作</th>\"); out.write(\"</tr>\"); out.write(\"</thead>\"); out.write(\"<tbody>\"); File file = new File(basePath); File[] list = file.listFiles(); System.out .println(\"basePath:\" + basePath + \"\\tlist.size:\" + list.length); int len = list.length; int no = 1; for (int i = 0; i < len; i++) { File f = list[i]; System.out.println(i + \"\\t\" + f.getName()); String fn = f.getName(); if (f.isFile() && fn.lastIndexOf(\"_\") > -1) { String filename = fn.substring(0, fn.lastIndexOf(\"_\")); String id = fn.substring(fn.lastIndexOf(\"_\")); String href1 = contextPath + DOWNLOAD + \"?id=\" + id; String href2 = contextPath + DELETE + \"?id=\" + id; StringBuilder sb = new StringBuilder(); sb.append(\"<tr>\"); sb.append(\"<td>\"); sb.append(no++); sb.append(\"</td>\"); sb.append(\"<td>\"); sb.append(filename); sb.append(\"</td>\"); sb.append(\"<td>\"); sb.append(\"<a href=\'\"); sb.append(href1); sb.append(\"\'>下载</a> <a href=\'\"); sb.append(href2); sb.append(\"\' onclick=\'return confirm(\\\"您确定要删除吗?\\\");\'>删除</a>\"); sb.append(\"</td>\"); sb.append(\"</tr>\"); out.write(sb.toString()); } } out.write(\"</tbody>\"); out.write(\"</table>\"); out.write(\"</body>\"); out.write(\"</html>\"); out.close(); } public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { System.out.println(\"doGet...\"); execute(req, resp); } public void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { System.out.println(\"doPost...\"); execute(req, resp); } private String getSuffix() { Date date = new Date(); SimpleDateFormat sdf = new SimpleDateFormat(\"yyyyMMddHHmmssSSS\"); String suffix = sdf.format(date); return suffix; } }
其实UploadService类可以直接实现service方法,而不用实现doGet、doPost方法。
以上servlet我也不想多解释什么,自己看代码吧。
五、效果图
1.项目结构图
2.404页面
/*会匹配所有包括空字符,所以图片中的路径会匹配,在UploadService中的if判断中出现在else中,因为此时的action是空字符。
3.文件列表页面
4.上传表单页面
5.下载
6.删除
7.文件找不到,如果你点删除时,文件在服务器上已经不存在,那么会进入此页面
8.打包的源码工程和war包
其中z-upload是eclipse源码工程,z-upload.war是打好的war包
全工程就两个jar包,一个web.xml和一个servlet类,可以自己从文章中拷贝过去测试一下,如果是懒人,可以下载
http://download.csdn.net/detail/yunsyz/9569680,特别提醒,下载要1分哦。
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持phpstudy。
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