java基于servlet編寫上傳下載功能 類似文件服務(wù)器
本人閑來(lái)無(wú)事,寫了個(gè)servlet,實(shí)現(xiàn)上傳下載功能。啟動(dòng)服務(wù)后,可以在一個(gè)局域網(wǎng)內(nèi)當(dāng)一個(gè)小小的文件服務(wù)器。
一、準(zhǔn)備工作
下載兩個(gè)jar包:
commons-fileupload-1.3.1.jar
commons-io-2.2.jar
二、創(chuàng)建一個(gè)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>
從以上配置可以看出,我的servlet類是UploadService,匹配的url是/*,意思是匹配所有訪問(wèn)url。
四、寫servlet類
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(); // 上傳文件的基本路徑 String basePath = servletContext.getRealPath(UPLOAD_DIR); // 上下文路徑 String contextPath = servletContext.getContextPath(); System.out.println("contextPath:" + contextPath); // 截取上下文之后的路徑 String action = uri.substring(contextPath.length()); System.out.println("action:" + action); // 依據(jù)action不同進(jìn)行不同的處理 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); // 創(chuàng)建監(jiān)聽 ProgressListener progressListener = new ProgressListener() { public void update(long pBytesRead, long pContentLength, int pItems) { System.out.println("當(dāng)前文件大小:" + pContentLength + "\t已經(jīng)處理:" + 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(); } } // 處理完后重定向到文件列表頁(yè)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) { // 處理完后重定向到文件列表頁(yè)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>您所訪問(wèn)的頁(yè)面不存在!<a href='" + href1 + "'>點(diǎn)擊</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 + "'>點(diǎn)擊</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='上傳'/><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?。∥募淮嬖诨蛭募呀?jīng)被刪除!<a href='" + href1 + "'>點(diǎn)擊</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 + "'>上傳</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>序號(hào)</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("'>下載</a> <a href='"); sb.append(href2); sb.append("' onclick='return confirm(\"您確定要?jiǎng)h除嗎?\");'>刪除</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; } }
其實(shí)UploadService類可以直接實(shí)現(xiàn)service方法,而不用實(shí)現(xiàn)doGet、doPost方法。
以上servlet我也不想多解釋什么,自己看代碼吧。
五、效果圖
1.項(xiàng)目結(jié)構(gòu)圖
2.404頁(yè)面
/*會(huì)匹配所有包括空字符,所以圖片中的路徑會(huì)匹配,在UploadService中的if判斷中出現(xiàn)在else中,因?yàn)榇藭r(shí)的action是空字符。
3.文件列表頁(yè)面
4.上傳表單頁(yè)面
5.下載
6.刪除
7.文件找不到,如果你點(diǎn)刪除時(shí),文件在服務(wù)器上已經(jīng)不存在,那么會(huì)進(jìn)入此頁(yè)面
8.打包的源碼工程和war包
其中z-upload是eclipse源碼工程,z-upload.war是打好的war包
全工程就兩個(gè)jar包,一個(gè)web.xml和一個(gè)servlet類,可以自己從文章中拷貝過(guò)去測(cè)試一下,如果是懶人,可以下載。
以上就是本文的全部?jī)?nèi)容,希望對(duì)大家的學(xué)習(xí)有所幫助,也希望大家多多支持腳本之家。
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