动手写一个java版简单云相册,实现的功能是：
用户可以一次上传一个至多个文件。
用户可以下载其他人上传的图片。
用户可以查看其他所有人的图片。
用户只能删除通过自己IP上传的图片。

用到的技术：
文件上传下载、设计模式、Dom4j、xPath等。

先看下2个页面：

源代码：

web.xml:

<?xml version="1.0" encoding="UTF-8"?><web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://mons.fileupload.servlet.ServletFileUpload;import cn.hncu.domain.PhotoModel;import cn.hncu.photoDao.Dao.PhotoDao;import cn.hncu.photoDao.factory.PhotoDaoFactory;import cn.hncu.utils.Dom4jFactory;import cn.hncu.utils.MyUtils;public class UploadServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=utf-8"); response.getWriter().print("<h1>很抱歉，本页面不支持GET方式访问！！！</h1>"); response.getWriter().print("<a href='javascript:history.go(-1)'>返回上一页</a> "); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=utf-8"); final PrintWriter out = response.getWriter(); //防黑-非multipart表单提交 //使用上传工具的方式 boolean boo = ServletFileUpload.isMultipartContent(request); if(!boo){ out.print("<h1>不支持普通表单的提交方式！</h1>"); return; } File file = new File("d:/photoCache"); if(!file.exists()){ file.mkdir(); } DiskFileItemFactory fiFactory = new DiskFileItemFactory(1024*10,file); ServletFileUpload upload = new ServletFileUpload(fiFactory); upload.setHeaderEncoding("utf-8");//设置文件名编码 String path = getServletContext().getRealPath("/photos"); FileItem fi = null; try { List<FileItem> list = upload.parseRequest(request); PhotoModel photo = new PhotoModel();//数据封装---需要7个属性 photo.setRealName(""); int cont=0; for(FileItem f:list){ if(cont!=0 && cont%2==0 && !photo.getRealName().equals("")){ photo = new PhotoModel();//重新数据封装 } fi=f; if(fi.isFormField()){//普通表单组件 //得到文件说明 String desc = fi.getString("utf-8"); photo.setDesc(desc);//#1 }else{ //防黑3-如果在file组件中不选择文件 if(fi.getSize()==0){ photo.setRealName(""); cont++; continue; } String fileName = fi.getName(); fileName = fileName.substring( fileName.lastIndexOf("\\")+1);//真实文件名 photo.setRealName(fileName);//#2 String ext = fileName.substring(fileName.lastIndexOf("."));//扩展名 photo.setExt(ext);//#3 photo.setDateTime(MyUtils.getCurrentDateTime());//#4 photo.setIp( request.getRemoteAddr() );//#5 String uuid = MyUtils.getUUID(); photo.setUuid(uuid);//#6 photo.setDir( MyUtils.getDir(uuid) );//#7 //打散目录 File dFile = new File(path+photo.getDir()); if(!dFile.exists()){ dFile.mkdirs(); } fi.write(new File(path+photo.getDir()+"/"+photo.getUuid()+photo.getExt())); } cont++; if(cont%2==0 && !photo.getRealName().equals("")){ PhotoDao dao = PhotoDaoFactory.getPhotoDao(); boo = dao.save(photo); //存入磁盘-法二：FileUtils.copyInputStreamToFile(in, new File(fileName2));//※2※ 把图片文件存储到服务器硬盘 photo = new PhotoModel();//重新数据封装 } } } catch (FileUploadException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); }finally{ if(fi!=null){ fi.delete(); } if(Dom4jFactory.save()){ out.print("<h1>上传成功！</h1>"); out.print("<a href='javascript:history.go(-1)'>返回上一页</a> "); }else{ out.print("<h1>上传失败！</h1>"); out.print("<a href='javascript:history.go(-1)'>返回上一页</a> "); } } }}

显示所有文件-cloudPhotoServlet.java

package cn.hncu.servlets;import java.io.IOException;import java.io.PrintWriter;import java.util.List;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import cn.hncu.domain.PhotoModel;import cn.hncu.photoDao.Dao.PhotoDao;import cn.hncu.photoDao.factory.PhotoDaoFactory;public class cloudPhotoServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String pwd = (String) request.getParameter("pwd"); if ("chx".equals(pwd)) { doPost(request, response); } else { response.setContentType("text/html;charset=utf-8"); response.getWriter().print("<h1>很抱歉，你没有权限访问！！！</h1>"); } } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=utf-8"); PrintWriter out = response.getWriter(); out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">"); out.println("<HTML>"); out.println(" <HEAD><TITLE>CHX云相册</TITLE></HEAD>"); out.println(" <BODY>"); out.println("<table border='1px;double;#ff0000'>"); out.println("<tr>"); out.println("<td>文件名</td>"); out.println("<td>上传时间"); out.println("<td>文件</td>"); out.println("<td>文件说明</td>"); out.println("<td>操作</td> "); out.println("</tr>"); String tdWH = "style='width:200px; height:200px;'"; // 显示所有图片 PhotoDao dao = PhotoDaoFactory.getPhotoDao(); List<PhotoModel> photos = dao.getAll(); for (PhotoModel photo : photos) { String fileName = photo.getRealName(); String time = photo.getDateTime(); // 输出图片 String path = request.getContextPath() + "/photos/" + photo.getDir() + "/" + photo.getUuid() + photo.getExt(); // System.out.println(path); // /myPhoto/photos//7/c/a1237a48a6aa451cb22fa78b15bafcea.jpg String img = "<a href='" + path + "'><img src='" + path + "'/></a>"; String desc = photo.getDesc(); String delStr = "<a href='/myPhoto/servlet/DelServlet?uuid=" + photo.getUuid() + "'>删除</a>"; String downStr = "<a href='/myPhoto/servlet/DownServlet?uuid=" + photo.getUuid() + "'>下载</a>"; out.println("<tr>"); out.println("<td " + tdWH + "> " + fileName + " </td>"); out.println("<td " + tdWH + ">" + time + "</td>"); out.println("<td " + tdWH + ">" + img + "</td>"); out.println("<td " + tdWH + ">" + desc + "</td>"); out.println("<td " + tdWH + ">" + delStr + "&nbsp;" + downStr + "</td>"); out.println("</tr>"); } out.println("<tr>"); out.println("</tr>"); out.println("</table>"); out.println(" </BODY>"); out.println("</HTML>"); out.flush(); out.close(); }}

删除文件-DelServlet.java

package cn.hncu.servlets;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import cn.hncu.domain.PhotoModel;import cn.hncu.photoDao.Dao.PhotoDao;import cn.hncu.photoDao.factory.PhotoDaoFactory;public class DelServlet extends HttpServlet { //注入 private PhotoDao dao = PhotoDaoFactory.getPhotoDao(); public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String uuid = request.getParameter("uuid"); String ip = request.getRemoteAddr(); response.setContentType("text/html;charset=utf-8"); PrintWriter out = response.getWriter(); PhotoModel photo = dao.getSingleByUuid(uuid); if(photo!=null){ if(!photo.getIp().equals(ip)){ out.print("<h1>你没有权限删除这个文件！！！</h1>"); out.print("<a href='javascript:history.go(-1)'>返回上一页</a> "); return ; } //1.删除数据库中的信息 boolean boo = dao.deleteXml(uuid); if(boo){ String fileName = "photos/"+photo.getDir()+"/"+photo.getUuid()+photo.getExt(); String pathFileName = getServletContext().getRealPath(fileName); if(dao.deleteFile(pathFileName)){ //重定向到相册页面 response.sendRedirect("/myPhoto/cloudPhoto?pwd=chx"); }else{ out.print("<h1>无法从服务器中删除，文件正在被占用！！！</h1>"); out.print("<a href='javascript:history.go(-1)'>返回上一页</a> "); } }else{ out.print("<h1>该文件已经不存在！！！</h1>"); out.print("<a href='javascript:history.go(-1)'>返回上一页</a> "); } } }}

下载文件-DownServlet.java

package cn.hncu.servlets;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.hncu.domain.PhotoModel;import cn.hncu.photoDao.Dao.PhotoDao;import cn.hncu.photoDao.factory.PhotoDaoFactory;public class DownServlet extends HttpServlet { private PhotoDao dao = PhotoDaoFactory.getPhotoDao(); public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String uuid = request.getParameter("uuid"); System.out.println(uuid); PhotoModel photo = dao.getSingleByUuid(uuid); System.out.println(photo); if(photo!=null){ //设置响应头--内容接收程序--浏览器看到这个响应头，就会把它认为的下载程序打开 //(如果识别迅雷那么就会自动打开迅雷，如果没有则会打开一个“文件另存为”的对话框) response.setContentType("application/force-download"); String realName = photo.getRealName(); String agent = request.getHeader("User-Agent"); System.out.println(agent); if(agent.indexOf("Mozilla")!=-1){//火狐浏览器 response.setHeader("Content-Disposition", "attachment;filename="+ new String(realName.getBytes("GB2312"),"ISO-8859-1")); }else{ //解决中文乱码问题（只要用下面一句对文件名进行编码就行了） realName = URLEncoder.encode(realName, "utf-8");//使用指定的编码机制将字符串转换为 application/x-www-form-urlencoded 格式。 response.setHeader("Content-Disposition", "attachment;filename=\""+realName+"\""); //注意：“cttachment;”不能少，否则浏览器会直接在新窗口中打开 } String fileName = "photos/" + photo.getDir()+"/"+photo.getUuid()+photo.getExt(); String pathFileName = getServletContext().getRealPath(fileName); InputStream in = new FileInputStream(pathFileName); OutputStream out = response.getOutputStream(); byte buf[] = new byte[2048]; int len=0; while( (len=in.read(buf))!=-1 ){ out.write(buf, 0, len); } out.close(); in.close(); }else{ response.setContentType("text/html;charset=utf-8"); response.getWriter().println("<h1>该文件已经被删除了</h1>"); } }}

演示结果

这个我就不演示啦，图片在前面也有，所有的源码我都给了。有兴趣的可以自己取改进一下咯。
其实这个还能上传其他任意类型文件哦，因为我们没有防护后缀名的，而且我们是用字符流传输，全都不会失真(可以当云盘来处理了~~)！！

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。