Java Web项目案例之

2023-08-10 05:48| 来源: 网络整理| 查看: 265

登录和注册（精华版）（一）实现功能

1.使用cookie记录登录成功的用户名，用户选择记住用户名，则用户再次登录时用户名自动显示

2.实现文件上传功能（上传文件的表单上传于普通的表单上传不同，必须是post，必须有value，enctype必须是multipart/form-data） 3.图片上传后的名称不能重复，使用随机生成的字符串（UUID）

4.实现图片显示功能（使用相对路径），通过session存放的地址信息，显示在页面中

5.使用session存放用户信息，在整个会话中都可以调用session中的信息

（二）页面显示

（三）代码实现

web.xml（配置）

DOCTYPEweb-appPUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd" > Archetype Created Web Application ts servlet.InitServlet 1 ts /y

pom.xml（配置）

commons-fileupload commons-fileupload 1.3.1 javax.servlet javax.servlet-api 3.1.0 provided

User.java

package entity; public class User { private String username; private String password; private String sex; private String hobby; private String path; public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } public String getHobby() { return hobby; } public void setHobby(String hobby) { this.hobby = hobby; } public String getPath() { return path; } public void setPath(String path) { this.path = path; } }

InitServlet.java

package servlet; import entity.User; import javax.servlet.ServletContext; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import java.util.ArrayList; import java.util.List; @WebServlet("/InitServlet") public class InitServlet extends HttpServlet { @Override public void init() throws ServletException { //创建一个List集合用于存放用户信息 List list=new ArrayList(); //将List集合中的信息保存到ServletContext中 this.getServletContext().setAttribute("list",list); } }

LoginServlet.java

package servlet; import entity.User; 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; import util.UploadUtil; import javax.servlet.ServletContext; 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 java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; @WebServlet("/LoginServlet") public class LoginServlet extends HttpServlet { @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { //数据的接收 //文件上传基本操作 try { //定义一个Map集合存放接收到的数据 Map map=new HashMap(); //1.创建一个磁盘文件项工厂对象 DiskFileItemFactory diskFileItemFactory=new DiskFileItemFactory(); //2.创建一个核心解析类 ServletFileUpload servletFileUpload=new ServletFileUpload(diskFileItemFactory); //3.解析request请求 List list=servletFileUpload.parseRequest(req); //定义一个List集合，用于保存复选框中的值 List hobbyList=new ArrayList(); //4.遍历集合，获得每个FileItem，判断是表单项还是文件上传项 String url=null; for(FileItem fileItem:list){ //判断是否是普通表单项 if(fileItem.isFormField()){ //接收表单项参数的值 String name=fileItem.getFieldName(); String value=fileItem.getString("UTF-8"); if("hobby".equals(name)){ //接收复选框的值 String hobbyvalue=fileItem.getString("UTF-8"); //将值存入hobbyList集合中 hobbyList.add(hobbyvalue); hobbyvalue=hobbyList.toString().substring(1,hobbyList.toString().length()-1); map.put(name,hobbyvalue); }else{ map.put(name,value); } }else{ //文件上传项 //文件上传功能 //获得文件上传的名称 String fileName=fileItem.getName(); //通过工具获得唯一文件名 String uuidFileName= UploadUtil.getUUIDFileName(fileName); //获得文件上传数据输入流 InputStream is=fileItem.getInputStream(); //获得文件上传相对路径 String path=this.getServletContext().getRealPath("/upload"); //将输入流对接到输出流 url=path+"//"+uuidFileName; OutputStream os=new FileOutputStream(url); int len=0; byte[] b=new byte[1024]; while((len=is.read(b))!=-1){ os.write(b,0,len); } is.close(); os.close(); } } User user=new User(); user.setUsername(map.get("username")); user.setPassword(map.get("password")); user.setSex(map.get("sex")); user.setHobby(map.get("hobby")); user.setPath(url); List userlist=(List)this.getServletContext().getAttribute("list"); userlist.add(user); System.out.println(user.getUsername()+","+user.getPassword()+","+user.getSex()+","+user.getHobby()+","+user.getPath()); resp.sendRedirect("login.jsp"); } catch (FileUploadException e) { e.printStackTrace(); } } @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doPost(req, resp); } }

LogonServlet.java

package servlet; import entity.User; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.*; import java.io.IOException; import java.util.List; @WebServlet("/LogonServlet") public class LogonServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doPost(req, resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String user=req.getParameter("user"); String password=req.getParameter("password"); String baocun=req.getParameter("baocun"); List list=(List)this.getServletContext().getAttribute("list"); for(User us:list){ if(us.getUsername().equals(user)&&us.getPassword().equals(password)){ //判断是否记住用户名 if("true".equals(baocun)){ //是，则将用户名存入cookie中 Cookie cookie=new Cookie("user",user); //在response中存入cookie resp.addCookie(cookie); } //在session中存入用户信息 HttpSession session=req.getSession(); session.setAttribute("user",us); req.getRequestDispatcher("/success.jsp").forward(req,resp); } else{ req.getRequestDispatcher("error.jsp").forward(req,resp); } } } }

UploadUtil.java

package util; import java.util.UUID; public class UploadUtil { //生成唯一的文件名 public static String getUUIDFileName(String fileName){ int idx=fileName.lastIndexOf("."); String extention=fileName.substring(idx); //生成随机字符串，避免文件名重复 String uuidFileName= UUID.randomUUID().toString().replace("-","")+extention; return uuidFileName; } }

index.jsp

Title 注册登录用户名：密码：性别：男女爱好：上传头像：

Title 登录注册用户名：密码：记住用户

success.jsp

Title 登录成功！

error.jsp

Title 登录失败！

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