登录注册和增删改查
（一）功能
1.使用了普通的jdbc和数据库连接池c3p0两种技术
2.使用了dao层（数据访问层），service层（业务逻辑层）和servlet层（请求控制层）
3.实现了增删改查和登录注册技术
（二）页面展示
1.登录页面
2.注册页面
3.登录成功页面
4.登录失败页面
5.修改页面
6.修改成功页面
7.删除成功页面
（三）代码展示
（1）entity
1.User.java
package entity; public class User { private int id; private String username; private String password; public int getId() { return id; } public void setId(int id) { this.id = id; } 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; } @Override public String toString() { return "User{" + "id=" + id + ", username='" + username + '\'' + ", password='" + password + '\'' + '}'; } }
（2）util
1.JDBCUtils.java 普通jdbc
package util; import com.mchange.v2.c3p0.ComboPooledDataSource; import java.io.IOException; import java.io.InputStream; import java.sql.*; import java.util.Properties; public class JDBCUtils { private static final String driverClass; private static final String url; private static final String username; private static final String password; static{ driverClass ="com.mysql.jdbc.Driver"; url ="jdbc:mysql://localhost:3306/zml"; username ="root"; password = "root"; } /** * 注册驱动的方法 * @throws ClassNotFoundException */ public static void loadDriver() throws ClassNotFoundException{ Class.forName(driverClass); } /** * 获得连接的方法: * @throws SQLException */ public static Connection getConnection() throws Exception{ loadDriver(); Connection conn = DriverManager.getConnection(url, username, password); return conn; } /** * 资源释放 */ public static void release(Statement stmt,Connection conn){ if(stmt != null){ try { stmt.close(); } catch (SQLException e) { e.printStackTrace(); } stmt = null; } if(conn != null){ try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } conn = null; } } public static void release(ResultSet rs,Statement stmt,Connection conn){ if(rs!= null){ try { rs.close(); } catch (SQLException e) { e.printStackTrace(); } rs = null; } if(stmt != null){ try { stmt.close(); } catch (SQLException e) { e.printStackTrace(); } stmt = null; } if(conn != null){ try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } conn = null; } } }
2.JDBCUtils2.java 数据连接池c3p0
package util; import com.mchange.v2.c3p0.ComboPooledDataSource; import javax.sql.DataSource; import java.beans.PropertyVetoException; import java.sql.Connection; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; /** * 数据连接池c3p0 */ public class JDBCUtils2 { private static final ComboPooledDataSource dataSource = new ComboPooledDataSource(); static{ try { dataSource.setDriverClass("com.mysql.jdbc.Driver"); dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/zml"); dataSource.setUser("root"); dataSource.setPassword("root"); } catch (PropertyVetoException e) { e.printStackTrace(); } } /** * 获得连接的方法: * @throws SQLException */ public static Connection getConnection() throws Exception{ Connection conn = dataSource.getConnection(); return conn; } /** * 资源释放 */ public static void release(Statement stmt, Connection conn){ if(stmt != null){ try { stmt.close(); } catch (SQLException e) { e.printStackTrace(); } stmt = null; } if(conn != null){ try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } conn = null; } } public static void release(ResultSet rs, Statement stmt, Connection conn){ if(rs!= null){ try { rs.close(); } catch (SQLException e) { e.printStackTrace(); } rs = null; } if(stmt != null){ try { stmt.close(); } catch (SQLException e) { e.printStackTrace(); } stmt = null; } if(conn != null){ try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } conn = null; } } }
（3）dao
1.LoginDao.java
package dao; import util.JDBCUtils; import util.JDBCUtils2; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; public class LoginDao { public boolean getLogin(String username,String password){ Connection conn=null; PreparedStatement pstmt=null; ResultSet rs=null; boolean flag=false; try{ //获得连接 conn = JDBCUtils2.getConnection(); //编写sql String sql="select password from user where username=? and password=?"; //预编译sql pstmt=conn.prepareCall(sql); pstmt.setString(1,username); pstmt.setString(2,password); //设置参数 //执行sql rs=pstmt.executeQuery(); if(rs.next()){ flag=true; }else{ flag=false; } }catch (Exception e){ }finally { JDBCUtils2.release(rs,pstmt,conn); } return flag; } }
2.RegisterDao.java
package dao; import entity.User; import util.JDBCUtils; import util.JDBCUtils2; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.util.ArrayList; import java.util.List; public class RegisterDao { public int getinsert(String username,String password){ Connection conn=null; PreparedStatement pstmt=null; int num=0; try { //获得连接 conn = JDBCUtils2.getConnection(); //编写sql String sql="insert into user values(null,?,?)"; //预编译sql pstmt=conn.prepareCall(sql); pstmt.setString(1,username); pstmt.setString(2,password); //设置参数 //执行sql num=pstmt.executeUpdate(); } catch (Exception e) { e.printStackTrace(); }finally { JDBCUtils2.release(pstmt,conn); } return num; } }
3.UserDao.java
package dao; import com.mchange.v2.c3p0.ComboPooledDataSource; import entity.User; import util.JDBCUtils; import util.JDBCUtils2; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; public class UserDao { public ListgetSelect(){ Connection conn=null; PreparedStatement pstmt=null; ResultSet rs=null; List user=new ArrayList (); User a=null; try { //获得连接 conn = JDBCUtils2.getConnection(); //编写sql String sql="select * from user"; //预编译sql pstmt=conn.prepareCall(sql); //设置参数 //执行sql rs=pstmt.executeQuery(); while(rs.next()){ a=new User(); a.setId(rs.getInt(1)); a.setUsername(rs.getString(2)); a.setPassword(rs.getString(3)); user.add(a); } } catch (Exception e) { e.printStackTrace(); }finally { JDBCUtils.release(rs,pstmt,conn); } return user; } }
4.UpdateDao.java
package dao; import entity.User; import util.JDBCUtils2; import java.sql.Connection; import java.sql.PreparedStatement; public class UpdateDao { public int getUpdate(User user){ Connection conn=null; PreparedStatement pstmt=null; int num=0; try { //获得连接 conn = JDBCUtils2.getConnection(); //编写sql String sql="update user set username=?,password=? where id=?"; //预编译sql pstmt=conn.prepareCall(sql); pstmt.setString(1,user.getUsername()); pstmt.setString(2,user.getPassword()); pstmt.setInt(3,user.getId()); //设置参数 //执行sql num=pstmt.executeUpdate(); } catch (Exception e) { e.printStackTrace(); }finally { JDBCUtils2.release(pstmt,conn); } return num; } }
5.DeleteDao.java
package dao; import util.JDBCUtils2; import java.sql.Connection; import java.sql.PreparedStatement; public class DeleteDao { public int getDelete(int id){ Connection conn=null; PreparedStatement pstmt=null; int num=0; try { //获得连接 conn = JDBCUtils2.getConnection(); //编写sql String sql="delete from user where id=?"; //预编译sql pstmt=conn.prepareCall(sql); pstmt.setInt(1,id); //设置参数 //执行sql num=pstmt.executeUpdate(); } catch (Exception e) { e.printStackTrace(); }finally { JDBCUtils2.release(pstmt,conn); } return num; } }
（4）service
1.UserService.java
package service; import dao.*; import entity.User; import java.util.List; public class UserService { public ListgetServlet(){ return new UserDao().getSelect(); } public boolean getLogin(String username,String password){ return new LoginDao().getLogin(username,password); } public int getinsert(String username,String password){ return new RegisterDao().getinsert(username,password); } public int getUpdate(User user){ return new UpdateDao().getUpdate(user); } public int getDelete(int id){ return new DeleteDao().getDelete(id); } }
（5）servlet
1.LoginServlet.java
package servlet; import service.UserService; 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.IOException; @WebServlet("/LoginServlet") public class LoginServlet extends HttpServlet { @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { req.setCharacterEncoding("UTF-8"); String username=req.getParameter("username"); String password=req.getParameter("password"); UserService log=new UserService(); boolean pwd=log.getLogin(username,password); System.out.println(password+" "+pwd); if(pwd==true){ req.getRequestDispatcher("UserServlet").forward(req,resp); }else{ req.getRequestDispatcher("error.jsp").forward(req,resp); } } @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doPost(req, resp); } }
2.RegisterServlet.java
package servlet; import service.UserService; 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.IOException; @WebServlet("/RegisterServlet") public class RegisterServlet 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 { req.setCharacterEncoding("UTF-8"); String username=req.getParameter("username"); String password=req.getParameter("password"); UserService u=new UserService(); int num=u.getinsert(username,password); if(num>0){ req.getRequestDispatcher("index.jsp").forward(req,resp); }else{ req.getRequestDispatcher("register.jsp").forward(req,resp); } } }
3.UserServlet.java
package servlet; import entity.User; import service.UserService; 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.IOException; import java.util.List; @WebServlet("/UserServlet") public class UserServlet 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 { UserService u=new UserService(); Listuser=u.getServlet(); System.out.println("udrt"+user); for(User uu:user){ System.out.println(uu.getId()+" "+uu.getUsername()+" "+uu.getPassword()); } req.setAttribute("User",user); req.getRequestDispatcher("success.jsp").forward(req,resp); } }
4.UpdateServlet.java
package servlet; import dao.UserDao; import entity.User; import service.UserService; 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.IOException; @WebServlet("/UpdateServlet") public class UpdateServlet extends HttpServlet { @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { req.setCharacterEncoding("UTF-8"); int id=Integer.decode(req.getParameter("id")); String username=req.getParameter("username"); String password=req.getParameter("password"); User user=new User(); user.setId(id); user.setUsername(username); user.setPassword(password); UserService u=new UserService(); int num=u.getUpdate(user); if(num>0){ req.getRequestDispatcher("LoginServlet").forward(req,resp); }else{ req.getRequestDispatcher("update.jsp").forward(req,resp); } } @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doPost(req, resp); } }
5.DeleteServlet.java
package servlet; import service.UserService; 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.IOException; @WebServlet("/DeleteServlet") public class DeleteServlet 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 { int id=Integer.decode(req.getParameter("id")); UserService u=new UserService(); int num=u.getDelete(id); req.getRequestDispatcher("UserServlet").forward(req,resp); } }
（6）webapp
1.index.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Titletitle> head> <body> <h2>登录h2><a href="register.jsp">注册a> <form action="LoginServlet" method="post"> 用户名：<input type="text" name="username"> 密码：<input type="text" name="password"> <input type="submit" value="确定"/> form> body> html>
2.register.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Titletitle> head> <body> <h2>注册h2><a href="index.jsp">a> <form action="RegisterServlet" method="post"> 用户名：<input type="text" name="username"> 密码： <input type="text" name="password"> <input type="submit" > form> body> html>
3.success.jsp
<%@ page import="entity.User" %> <%@ page import="java.util.List" %> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Titletitle> head> <body> <table> <tr> <td>idtd> <td>用户名td> <td>密码td> <td>修改td> <td>删除td> tr> <% List<User> us=(List<User>)request.getAttribute("User"); for(User u:us){%> <tr> <td><%=u.getId()%>td> <td><%=u.getUsername()%>td> <td><%=u.getPassword()%>td> <td><a href="update.jsp?id=<%=u.getId()%>&&username=<%=u.getUsername()%>&&password=<%=u.getPassword()%>">修改a>td> <td><a href="DeleteServlet?id=<%=u.getId()%>">删除a> td> tr> <%}%> table> body> html>
4.error.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Titletitle> head> <body> 账户名或密码错误！ body> html>
5.update.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Titletitle> head> <body> <form action="UpdateServlet" method="post"> <table> <tr> <td>idtd> <td><input type="text" name="id" value="<%=request.getParameter("id")%>">td> tr> <tr> <td>用户名td> <td><input type="text" name="username" value="<%=request.getParameter("username")%>">td> tr> <tr> <td>密码td> <td><input type="text" name="password" value="<%=request.getParameter("password")%>">td> tr> table> <input type="submit"> form> body> html>
（7）pom.xml
<dependency> <groupId>javax.servletgroupId> <artifactId>javax.servlet-apiartifactId> <version>3.1.0version> <scope>providedscope> dependency> <dependency> <groupId>org.springframeworkgroupId> <artifactId>spring-jdbcartifactId> <version>5.1.5.RELEASEversion> dependency> <dependency> <groupId>com.mchangegroupId> <artifactId>c3p0artifactId> <version>0.9.5.2version> dependency> <dependency> <groupId>mysqlgroupId> <artifactId>mysql-connector-javaartifactId> <version>5.1.25version> dependency>