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  • MVC的一个简单实例

    基本思路:

      一个Regist.jsp注册页面,用于收集用户信息,发送请求给控制器Servlet;控制器层Servlet封装模型层对象 jBean,并调用其方法regiser实现用户信息的保存;模型层JavaBean.java 接收控制器层的对象,完成对数据库的操作。

    话不多说,上代码。

    首先有个数据库访问公共类,以后凡是操作数据库的页面都可以调用。不容多说:

    Unilt.java

    /**
     * 
     */
    package javaBeanServlet;
    
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.sql.Statement;
    
    /**
     * @author Administrator
     *
     */
    public class Unilt {
        private static final String URL = "jdbc:mysql://localhost:3306/userdb";
        private static final String USER = "root";
        private static final String PASSWORD = "111111";
        protected static Statement s = null;
        protected static ResultSet rs = null;
        protected static Connection coon = null;
        public static synchronized Connection getConnection() {
            try {
                Class.forName("com.mysql.jdbc.Driver");
            } catch (ClassNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            try {
                coon = DriverManager.getConnection(URL, USER, PASSWORD);
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return coon;
        }
        public static int executeUpdate(String sql) {
            int result = 0;
            try {
                s = getConnection().createStatement();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            try {
                result = s.executeUpdate(sql);
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return result;
        }
        public static ResultSet executeQuery(String sql) {
            try {
                s = getConnection().createStatement();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            try {
                rs = s.executeQuery(sql);
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return rs ;
        }
        public static PreparedStatement executePreparedStatement(String sql) {
            PreparedStatement ps = null;
            try {
                ps = getConnection().prepareStatement(sql);
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return ps;
        }
        public static void rollback() {
            try {
                getConnection().rollback();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        public static void close() {
            if (rs != null) {
                try {
                    rs.close();
                } catch (SQLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            if (s != null) {
                try {
                    s.close();
                } catch (SQLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            if (coon != null) {
                try {
                    coon.close();
                } catch (SQLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }
    View Code

    接下来是一个简单的注册页面:

    Register.jsp

    <%@ page language="java" contentType="text/html; charset=utf-8"
        pageEncoding="utf-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
    <title>Insert title here</title>
    </head>
    <body>
            <form action = "/ch1/Servelt" method = "post">
                <input type ="text" value = "username" name = "username"/>
                <input type ="password" value = "password" name = "password"/>
                <input type = "submit" value = "提交" name = "submit" />
            </form>
    </body>
    </html>
    View Code

    Servlet.java

    package javaBeanServlet;
    import java.io.IOException;
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    /**
     * Servlet implementation class Servelt
     */
    @WebServlet("/Servelt")
    public class Servelt extends HttpServlet {
        private static final long serialVersionUID = 1L;
           
        /**
         * @see HttpServlet#HttpServlet()
         */
        public Servelt() {
            super();
            // TODO Auto-generated constructor stub
        }
    
        /**
         * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
         */
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            // 设置编码格式
            response.setCharacterEncoding("utf-8");
            response.setContentType("text/html;charset = utf-8"); 
            /* 实例化JavaBean 的一个对象 jBean ,并通过request.getParameter()获取Regist表单提交的
               username、password值    
            */
            JavaBean jBean = new JavaBean();
            jBean.setFd_username(request.getParameter("username"));
            jBean.setFd_password(request.getParameter("password"));
            jBean.register(jBean);
        }
    
        /**
         * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
         */
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            // TODO Auto-generated method stub
            doGet(request, response);
        }
    
    }
    View Code

    JavaBean.java

    /**
     * 
     */
    package javaBeanServlet;
    import java.sql.*;
    import javaBeanServlet.*;
    import javaBeanServlet.Unilt;
    /**
     * @author Administrator
     *
     */
    public class JavaBean {
        // 依据数据表结构声明成员变量
        private String fd_username ;
        private String fd_password ;
        // 为属性提供setter和getter方法
        public String getFd_username() {
            return fd_username;
        }
        public void setFd_username(String fd_username) {
            this.fd_username = fd_username;
        }
        public String getFd_password() {
            return fd_password;
        }
        public void setFd_password(String fd_password) {
            this.fd_password = fd_password;
        }
        
        public boolean register(JavaBean javaBean){
            String sql = "insert into users(username ,password) values (?,?)";
            int result = 0;
            PreparedStatement ps = Unilt.executePreparedStatement(sql);
            try {
                ps.setString(1,javaBean.fd_username);
                ps.setString(2,javaBean.fd_password);
                result = ps.executeUpdate();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            // 注册成功,返回true;注册失败,返回false
            if (result > 0) {
                System.out.println("注册成功");
                return true;    
            }
            else {
                System.out.println("注册失败");
                return false;
            }
        }
    }
    View Code

    下面是运行的效果:

        新手上路,请多指教!

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  • 原文地址:https://www.cnblogs.com/qzhc/p/11203213.html
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