任务
1.通过连接数据库完成用户登录模块。
2.登录成功后查询出一张数据库表中的内容；登录不成功返回登录页面。
3.页面面端要有空值和非法字符验证。
4.登录成功后对一张表中数据进行增加、删除、修改和查询操作。
代码
数据库相关代码
创建数据库
名字为jdbcHomework，字符编码为utf8
数据库创建表
学生表
DROP TABLE IF EXISTS `student`;CREATE TABLE `student` (`Sid` char(11) CHARACTER SET utf8 NOT NULL,`Sname` char(50) CHARACTER SET utf8 DEFAULT NULL,`Ssex` char(2) CHARACTER SET utf8 DEFAULT NULL,`Sclass` char(50) CHARACTER SET utf8 DEFAULT NULL,`Syuanxi` char(50) CHARACTER SET utf8 DEFAULT NULL,PRIMARY KEY (`Sid`)) ENGINE=InnoDB DEFAULT CHARSET=latin1 COMMENT='jdbc作业';用户表
DROP TABLE IF EXISTS `user`;CREATE TABLE `user` (`Userid` char(11) NOT NULL,`Username` char(50) DEFAULT NULL,`Userpwd` varchar(12) DEFAULT NULL,PRIMARY KEY (`Userid`)) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='jdbc作业';数据库的表中插入数据
学生表
INSERT INTO `student` VALUES ('20221104122', '李静静', '女', '计科（专升本）1班', '计算机');INSERT INTO `student` VALUES ('20221104204', '柯柯', '女', '计科（专升本）2班', '计算机');INSERT INTO `student` VALUES ('20221104250', 'zyp', '男', '自动化1班', '自动化');用户表
INSERT INTO `user` VALUES ('20221104122', '洛可可', '666666');INSERT INTO `user` VALUES ('root', '洛可可', 'root');myeclipse中代码
src的jdbcHomework包中的代码
功能：连接数据库
1.LinkMysql.java为连接mysql的代码，包括驱动、密码、url，用于登录界面、登录检查、增删改查的后台处理
2.ConnectionFactory.java为为连接mysql的代码，包括驱动、密码、url，用于登录成功后界面linkMysql.jsp连接数据库
3.本次学习时上面类使用方法是通过javaBean的id获取链接，从而连接到数据库；下面类使用方法是通过在开头导入该类，代码中新建类并用 “新建的类名.getConnection();” 方法获取链接，从而连接到数据库
1．LinkMysql
package jdbcHomework;import java.sql.*;public class LinkMysql { //驱动程序private String driverName = "com.mysql.jdbc.Driver";//设置数据库连接URLprivate String url = "jdbc:mysql://localhost:3306/jdbcHomework" />;private String user = "root";//数据库登录用户名private String password = "root";//数据库登录密码 public String getDriverName() {return driverName;}public void setDriverName(String driverName) {this.driverName = driverName;}public String getUrl() {return url;}public void setUrl(String url) {this.url = url;}public String getUser() {return user;}public void setUser(String user) {this.user = user;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;} public Connection getConnection() {try {Class.forName(driverName);return DriverManager.getConnection(url, user, password);} catch (Exception e) {//e.printStackTrace();System.out.println("驱动异常");return null;}}}2.ConnectionFactory
package jdbcHomework;import java.sql.Connection;import java.sql.DriverManager;import java.sql.SQLException;public class ConnectionFactory {private String driverClassName = "com.mysql.jdbc.Driver"; private String url = "jdbc:mysql://localhost:3306/jdbcHomework?useUnicode=true&characterEncoding=utf-8"; private String userName = "root"; private String password = "root"; /* private static ConnectionFactory connectionFactory=null; private ConnectionFactory() { try {Class.forName(driverClassName);} catch (ClassNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} }public ConnectionFactory(){} */public Connection getConnection() throws SQLException { try {Class.forName(driverClassName);} catch (ClassNotFoundException e) {// TODO Auto-generated catch block//e.printStackTrace();System.out.println("驱动异常");} return DriverManager.getConnection(url, userName, password); }/*public static ConnectionFactory getInstance() {if (null==connectionFactory) { connectionFactory=new ConnectionFactory(); } return connectionFactory;}*/}WebRoot/jdbcHomework下的代码
1.登录主界面代码
login.jsp
<%@ page language="java" import="java.util.*,java.sql.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>My JSP 'login.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"><meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--> <script type="text/javascript">function checkForm(){if (form1.id.value == null || form1.userid.value==""){alert("请输入学号");return false ;}if (form1.name.value == null || form1.username.value==""){alert("请输入姓名");return false ;}if (form1.pwd.value == null || form1.pwd.value==""){alert("请输入密码");return false;}return true;}</script></head><body bgcolor="pink"><div class="top" align="center"> <h1>欢迎来到洛可可学生管理系统！！</h1></div><div class="center" align="center"> <table border="1" bgcolor="rgb(248, 169, 182)"><form name="form1" action="logincheck.jsp" method="post" onsubmit="return checkForm();"><tr><td>学号：</td><td><input type="text" name="id" ></td></tr><tr><td>姓名：</td><td><input type="text" name="name" ></td></tr><tr><td>密码：</td><td width="50"><input type="password" name="pwd"></td></tr><tr ><td colspan="2" align="center"><input type="submit" value="登录"/><input type="reset"/></td></tr></form></table> </div><div class="bottom" align="center"></div> </body></html>2.登录检查代码
logincheck.jsp
<%@ page language="java" import="java.util.*,java.sql.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>My JSP 'logincheck.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"><meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><body><jsp:useBean id="link" class="jdbcHomework.LinkMysql"></jsp:useBean><%/*获取到login.jsp页面登录时学生的学号、姓名、密码*/request.setCharacterEncoding("utf-8");String studentId = request.getParameter("id");String studentName = request.getParameter("name");String pwd = request.getParameter("pwd");System.out.println("学号："+studentId+"，姓名："+studentName+"，密码："+pwd);//控制台输出获取到的登录时学生的学号、姓名、密码/*连接数据库并执行相关操作*/ Connection con=null; PreparedStatement ps=null; ResultSet rs=null;con = link.getConnection();String sql="select * from user where Userid=? and Username=? and Userpwd=?"; ps=con.prepareStatement(sql); ps.setString(1,studentId); ps.setString(2, studentName); ps.setString(3,pwd);rs=ps.executeQuery();if(rs.next()){System.out.println("登录成功！"); response.sendRedirect("linkMysql-2.jsp");} else{System.out.println("登录失败！"); response.sendRedirect("login.jsp"); out.print(" alert('登陆失败,请重新登录！！');window.location='login.jsp';");}rs.close();ps.close();con.close(); %> </body></html>3.登录成功页面代码
linkMysql-2.jsp
<%@ page language="java" import="java.util.*, java.sql.*,jdbcHomework.ConnectionFactory" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>My JSP 'linkMysql.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"><meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><%-- 在浏览器上显示所有学生信息 --%><body bgcolor="pink"><div class="top" align="center" ><h1>欢迎加入到洛可可学生管理系统</h1></div> <div class="center" align="center"><table border="1" bgcolor="rgb(248, 169, 182)"align="center"><tr><th width="87" align="center">学号</th><th width="87" align="center">姓名</th><th width="87" align="center">性别</th><th width="87" align="center">班级</th><th width="87" align="center">院系</th> <th width="87" align="center">操作</th></tr><% Connection con= null;Statement stmt=null;ResultSet rs=null;//Class.forName("com.mysql.jdbc.Driver");/*3306为端口号，student为数据库名，url后面加的?useUnicode=true&characterEncoding=gbk是为了处理向数据库中添加数据时出现乱码的问题。*///String url="jdbc:mysql://localhost:3306/jdbcHomework?useUnicode=true&characterEncoding=utf-8";//con=DriverManager.getConnection(url,"root","root");ConnectionFactory cf = new ConnectionFactory();con = cf.getConnection();;int intPageSize; //一页显示的记录数int intRowCount; //记录总数int intPageCount;//总页数int intPage; // 待显示页码String strPage;int i;intPageSize=10; //设置一页显示的记录数strPage = request.getParameter("page");if(strPage==null){//表明page的参数值为空，此时显示第一页数据intPage = 1;}else{//将字符串转换成整型intPage = java.lang.Integer.parseInt(strPage);if(intPage<1)intPage=1;}stmt=con.createStatement();String sql="select * from student";rs=stmt.executeQuery(sql);while(rs.next()){%><tr> <td><%=rs.getString("Sid")%></td> <td><%=rs.getString("Sname")%></td> <td><%=rs.getString("Ssex")%></td> <td><%=rs.getString("Sclass")%></td> <td><%=rs.getString("Syuanxi")%></td><td><a href="deleteStu.jsp?Sid=<%=rs.getString("Sid")%>">删除</a><a href="updateStu.jsp?Sid=<%=rs.getString("Sid")%>">修改</a></td></tr> <%}rs.close();stmt.close();con.close();%> </table></div><br><div class="bottom" align="center"><a href="add.jsp">添加学生信息</a><a href="login.jsp">登录界面</a></div></body></html>4.删除学生信息主界面代码
deleteStu.jsp
<%@ page language="java" import="java.util.*,java.sql.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>My JSP 'deleteStu.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"><meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><body><jsp:useBean id="link" class="jdbcHomework.LinkMysql"></jsp:useBean><% request.setCharacterEncoding("utf-8"); String sid = request.getParameter("Sid"); System.out.println(sid); Connection con=null; PreparedStatement ps=null; //ResultSet rs=null; con = link.getConnection();String sql="delete from student where Sid=? "; ps=con.prepareStatement(sql); ps.setString(1,sid); int i=ps.executeUpdate();if(i>0){System.out.println("删除成功！"); response.sendRedirect("linkMysql.jsp"); //out.print(" alert('删除成功！');window.location='linkMysql.jsp';"); } else{System.out.println("删除的学生不存在！"); response.sendRedirect("linkMysql.jsp"); //out.print(" alert('删除失败！');window.location='login.jsp';");}ps.close();con.close();%></body></html>5.修改学生信息主界面代码
deleteStu.jsp
<%@ page language="java" import="java.util.*, java.sql.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>My JSP 'updateStu.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"><meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><body bgcolor="pink"><div class="top" align="center"><h1>欢迎来到洛可可学生系统修改（更新）页面</h1></div><hr> <div class="center" align="center"> <jsp:useBean id="link" class="jdbcHomework.LinkMysql"></jsp:useBean><%String sid = request.getParameter("Sid");System.out.println(sid);Connection con=null; PreparedStatement ps=null;con=link.getConnection(); String sql="select * from student where Sid=? "; ps=con.prepareStatement(sql); ps.setString(1,sid); ResultSet rs=ps.executeQuery(); if(rs.next()){ %> <form action="doupdate.jsp" method="post" > <table border="1" bgcolor="rgb(248, 169, 182)" > <tr><th>学号：</th> <td><%=rs.getString(1) %></td> </tr> <tr> <th>姓名：</th> <td><input type="text" name="sname" value=""></td> </tr> <tr> <th>性别：</th> <td><input type="text" name="ssex" value=""></td> </tr> <tr> <th>班级：</th> <td><input type="text" name="banji" value=""></td> </tr> <tr> <th>院系：</th> <td><input type="text" name="yuanxi" value=""></td> </tr></table> <br> <input type="submit" value="修改完成"> </form><% //out.print(" alert('登陆成功！');window.location='linkMysql.jsp';"); } else{System.out.println("学生不存在！"); response.sendRedirect("linkMysql.jsp"); //out.print(" alert('登录失败！');");//out.print(" alert('登陆失败！');window.location='login.jsp';");}rs.close();ps.close();con.close();%> </div> <hr><br><div class="bottom" align="center"> <a href="linkMysql-2.jsp">返回上一界面</a><a href="login.jsp">登录界面</a> </div></body></html>6.修改学生信息后台处理代码
doupdate.jsp
<%@ page language="java" import="java.util.*,java.sql.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>My JSP 'doupdate.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"><meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><body><jsp:useBean id="link" class="jdbcHomework.LinkMysql"></jsp:useBean><%request.setCharacterEncoding("utf-8");String uid = request.getParameter("sid");String uname = request.getParameter("sname");String sex = request.getParameter("ssex");String banji = request.getParameter("banji");String yuanxi = request.getParameter("yuanxi");System.out.println(uid+uname+sex+banji+yuanxi);Connection con=null;PreparedStatement ps=null; con=link.getConnection(); String sql="update student set Sname=?,Ssex=?,Sclass=?,Syuanxi=? where Sid=?"; ps=con.prepareStatement(sql); ps.setString(1,uname); ps.setString(2, sex); ps.setString(3,banji);ps.setString(4,yuanxi); ps.setString(5,uid);int i=ps.executeUpdate(); if(i>0){System.out.println("修改成功！"); response.sendRedirect("linkMysql.jsp"); //out.print(" alert('学生信息修改成功！');window.location='linkMysql.jsp';"); } else{System.out.println("修改失败！"); response.sendRedirect("linkMysql.jsp"); //out.print(" alert('学生信息修改失败！');window.location='login.jsp';");} ps.close();con.close(); %></body></html>6.添加学生信息主界面代码
add.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>My JSP 'add.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"><meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--><script type="text/javascript">function checkForm(){if (form1.id.value == null || form1.userid.value==""){alert("请输入学号");return false ;}if (form1.name.value == null || form1.username.value==""){alert("请输入姓名");return false ;}if (form1.sex.value == null || form1.sex.value==""){alert("请输入性别");return false;}if (form1.banji.value == null || form1.banji.value==""){alert("请输入班级");return false;}if (form1.yuanxi.value == null || form1.yuanxi.value==""){alert("请输入院系");return false;}return true;}</script></head><body bgcolor="pink"><div class="top" align="center"><h1>欢迎来到洛可可学生系统添加页面</h1></div><div class="center" align="center"><table><form name="form1" action="doadd.jsp" method="post" onsubmit="return checkForm();"><tr><td>学号：</td><td><input type="text" name="id" ></td></tr><tr><td>姓名：</td><td><input type="text" name="name" ></td></tr><tr><td>性别：</td><td width="50"><input type="text" name="sex"></td></tr><tr><td>班级：</td><td width="50"><input type="text" name="banji"></td></tr><tr><td>院系：</td><td width="50"><input type="text" name="yuanxi"></td></tr><tr ><td colspan="2" align="center"><input type="submit" value="添加"/><input type="reset"/></td> </tr> </form> </table> </div><br> <div align="center"> <a href="linkMysql-2.jsp">返回上一界面</a> <a href="login.jsp">切换账号</a> </div></body></html>6.添加学生信息后台处理代码
doadd.jsp
<%@ page language="java" import="java.util.*,java.sql.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>My JSP 'doadd.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"><meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><body><jsp:useBean id="link" class="jdbcHomework.LinkMysql"></jsp:useBean><% request.setCharacterEncoding("utf-8");String uid = request.getParameter("id");String uname = request.getParameter("name");String sex = request.getParameter("sex");String banji = request.getParameter("banji");String yuanxi = request.getParameter("yuanxi");Connection con=null; PreparedStatement ps=null; con = link.getConnection();String sql="insert into student(Sid,Sname,Ssex,Sclass,Syuanxi) values(?,?,?,?,?)"; ps=con.prepareStatement(sql); ps.setString(1,uid); ps.setString(2, uname); ps.setString(3,sex);ps.setString(4,banji); ps.setString(5,yuanxi);int i=ps.executeUpdate();if(i>0){System.out.println("添加成功！"); response.sendRedirect("linkMysql.jsp"); //out.print(" alert('添加成功！');window.location='linkMysql.jsp';"); } else{System.out.println("添加失败！"); response.sendRedirect("linkMysql.jsp");//out.print(" alert('添加失败！');window.location='login.jsp';");} ps.close();con.close(); %></body></html>问题
1.login.jsq页面的表单接收地址为jdbcHomework/logincheck.jsp 时，只有初始时主界面登录才会进去，通过别的界面打开的登录界面输入正确信息会报404地址错误
2.login.jsq页面的表单接收地址为logincheck.jsp 效果：只有通过别的界面打开的登录界面输入正确信息才会进入登录成功界面,初始时的登录界面输入正确信息点击登录时会报404错误
解决方法
解决方法：写两个登录界面，
初始时主界面登录的表单接受地址写为jdbcHomework/logincheck.jsp
别的界面跳转时的登录界面地址写为logincheck.jsp
地址写绝对地址：/项目名/相对于webroot的相对地址
效果
运行初始界面
输入错误用户信息登录返回登录页面
输入正确用户信息登录进入系统
输入正确学号、姓名、密码后控制台输出登录成功，页面跳转至登录成功页面（显示数据库学生信息表）
删除学生信息功能
在主界面信息每行后面都有一个删除选项，点击即可删除该行信息
删除前
删除后
修改学生信息功能
在主界面信息每行后面都有一个修改选项，点击即可跳转至修改该行信息页面，可以修改该行信息（学号不可更改）
修改信息页面
点击各个信息（姓名、性别、班级、院系）修改，修改完成后点击修改完成跳转至登录成功界面
点击返回上一界面，即跳转到登录成功界面
点击登录界面，即跳转到登录界面
添加学生信息功能
在主界面信息表后面都有一个添加学生信息选项，点击即可跳转至学生信息添加页面，之后输入信息点击添加即可完成添加学生信息功能
学生信息添加页面
输入信息点击添加即可完成添加学生信息功能
控制台显示添加成功
点击重置可重新输入
点击返回上一界面，跳转至登录成功页面
点击切换账号，跳转至登录界面
