不说废话，首先，建立要连接的数据库，我的数据库名称是collage，要显示的数据表是students，有六列，要学习并测试的可以自己建立数据库。 id:int
name:varchar
grade:int
batch:int
password:int
gxqm:varchar
JSP页面，有三个，login.jsp,loginhandle.jsp,welcome.jsp。java类有三个，Userbean用于映射数据对象，UserbeanCl用于业务逻辑处理，connDB用于建立数据库连接。直接上代码吧
login.jsp页面
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" ""> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Login in and then enjoy yourself!</title> </head> <body> <center> 请登录 <form name="form1" action="loginhandle.jsp"> <hr color="cc00aa"> 用户名: <input type="text" name="user"> <br> 密 码: <input type="password" name="password"> <br> <input type="submit" value="登录"> <input type="reset" name="重置"> </form> </center> </body> </html>
loginhandle页面：
<%@ page language="java" import="java.sql.*" import="java.util.*,com.ly.model.UserbeanCl" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" ""> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>here</title>
</head> <body> <center> <br> <% String u = request.getParameter("user"); String p = request.getParameter("password"); // 一、普通验证 /* if(u.equals("Liyong")&&p.equals("woaini")){ response.sendRedirect("welcome.jsp?user="+u);//跳转到欢迎界面并传递出用户名user } else{ response.sendRedirect("login.jsp"); } */ // 二、直接到数据库中验证 // DriverManager.registerDriver(new com.mysql.jdbc.Driver()); // Class.forName("com.mysql.jdbc.Driver"); /* try { Class.forName("com.mysql.jdbc.Driver"); } catch (ClassNotFoundException e) { e.printStackTrace(); } Connection ct = DriverManager.getConnection( "jdbc:mysql://localhost:3306/collage", "root", ""); Statement st = ct.createStatement(); ResultSet rs = st.executeQuery("select password from students where name='" + u + "'"); if (rs.next()) { //说明用户名存在 if (rs.getString(1).equals(p)) { //密码正确 response.sendRedirect("welcome.jsp?user=" + u);//跳转到欢迎界面并传递出用户名user } else { response.sendRedirect("login.jsp");
} } rs.close(); st.close(); ct.close(); */ // 三、通过userbeanCl对用户进行验证 UserbeanCl ubc=new UserbeanCl(); if(ubc.checkUser(u,p)) { response.sendRedirect("welcome.jsp?user=" + u); }else { out.println("<script>alert('密码或者用户名错误！');</script>"); Thread.sleep(1000); response.sendRedirect("login.jsp"); // return; }
%> </center> </body> </html>
welcome页面：
<%@ page language="java" import="java.util.*,com.ly.model.*" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" ""> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Welcome your mother!</title> </head> <body> <center> Hello,world! <br> <%=request.getParameter("user")%> <br> <a href="login.jsp">返回重新登录</a> <hr color="silver"> <br> 用户信息列表 <br> <% int pageNow=1; String u=request.getParameter("user"); String s_pageNow=request.getParameter("pageNow"); if(s_pageNow!=null){ pageNow=Integer.parseInt(s_pageNow); } // 调用UserbeanCl的方法，完成分页显示 UserbeanCl ubc=new UserbeanCl(); int pageCount=ubc.pageCount(); ArrayList al=ubc.getUsersByPage(pageNow); %> <table border="1"> <tr> <td>用户Id</td> <td>姓名</td> <td>班级</td> <td>批次</td> <td>密码</td> <td>个性签名</td> </tr> <% for(int i=0;i<al.size();i++){ Userbean usb=(Userbean)al.get(i); // System.out.println("-----------------"+usb.getGxqm()); %> <tr> <td><%=usb.getId() %></td> <td><%=usb.getName() %></td> <td><%=usb.getGrade() %></td> <td><%=usb.getBatch() %></td> <td><%=usb.getPassword() %></td> <td><%=usb.getGxqm() %></td> </tr> <%
} %> </table> <br><hr color="blue"><br> <% //显示上一页 out.println("<a href=welcome.jsp?pageNow="+1+"&user="+u+">首页</a>"); if(pageNow!=1){ out.println("<a href=welcome.jsp?pageNow="+(pageNow-1)+"&user="+u+">上一页</a>"); } // 显示页码 for(int i=pageNow;i<=(pageCount<(pageNow+5)?pageCount:(pageNow+5));i++){ out.println("<a href=welcome.jsp?pageNow="+i+"&user="+u+">["+i+"]</a>"); } if(pageNow!=pageCount){ out.println("<a href=welcome.jsp?pageNow="+(pageNow+1)+"&user="+u+">下一页</a>"); } out.println("<a href=welcome.jsp?pageNow="+pageCount+"&user="+u+">尾页</a>"); %> </center> </body> </html>
Userbean.java实现数据对象的封装
package com.ly.model;
public class Userbean { private int id; private String name; private int grade; private int batch; private int password; private String gxqm; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getGrade() { return grade; } public void setGrade(int grade) { this.grade = grade; } public int getBatch() { return batch; } public void setBatch(int batch) { this.batch = batch; } public int getPassword() { return password; } public void setPassword(int password) { this.password = password; } public String getGxqm() { return gxqm; } public void setGxqm(String gxqm) { this.gxqm = gxqm; } }
connDB.java实现数据库的连接//得到数据库的连接
//得到数据库的连接 package com.ly.model; import java.sql.*; import java.util.*; public class connDB { private Connection ct=null; public Connection getConn(){ try { Class.forName("com.mysql.jdbc.Driver"); ct=DriverManager.getConnection("jdbc:mysql://localhost:3306/collage", "root", ""); } catch (Exception e) { e.printStackTrace(); } return ct; } }UserbeanCl.java实现业务逻辑的处理
//这是一个处理类，主要封装对User表的各种操作，包括增删改查
package com.ly.model;
import java.sql.*; import java.util.ArrayList;
public class UserbeanCl { private Statement st = null; private ResultSet rs = null; private Connection ct = null; private int pageSize = 10; private int rowCount = 0; private int pageCount = 0;
// 验证用户是否存在 public int pageCount() { try { // 得到连接 ct = new connDB().getConn(); st=ct.createStatement(); rs = st.executeQuery("select count(*) from students"); // if(rs.next()){ rowCount=rs.getInt(1); } if(rowCount%pageSize==0){ pageCount=rowCount/pageSize; }else{ pageCount=rowCount/pageSize+1; } } catch (Exception e) { e.printStackTrace(); } finally { shutup(); } return pageCount;
}
public ArrayList getUsersByPage(int PageNow) { pageCount = pageCount(); ct = new connDB().getConn(); int startRow=(PageNow-1)*pageSize; ArrayList al = new ArrayList(); try { st = ct.createStatement(); rs=st.executeQuery("SELECT id,name,grade,batch,password,gxqm FROM `students` LIMIT "+startRow+","+pageSize); while(rs.next()){ Userbean ub=new Userbean(); ub.setId(rs.getInt(1)); ub.setName(rs.getString(2)); ub.setGrade(rs.getInt(3)); ub.setBatch(rs.getInt(4)); ub.setPassword(rs.getInt(5)); ub.setGxqm(rs.getString(6)); // System.out.println(rs.getString(6)); al.add(ub); }
} catch (Exception e) { e.printStackTrace(); } finally { shutup(); }
return al;
}
public boolean checkUser(String u, String p) { boolean b = false; ct = new connDB().getConn(); try { st = ct.createStatement(); ResultSet rs = st .executeQuery("select password from students where name='" + u + "'"); if (rs.next()) { // 说明用户名存在 if (rs.getString(1).equals(p)) { // 密码正确 b = true; } else { return false; } }
} catch (Exception e) { e.printStackTrace(); } finally { shutup(); } return b;
}
public void shutup() {
try { if (rs != null) rs.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } finally { try { if (st != null) st.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } finally { try { if (ct != null) ct.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }
}
}