JavaWeb练手小Demo

最新推荐文章于 2024-07-04 18:06:06 发布

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#intellij-idea #java #intellij idea

C3p0数据源的操作：

通过ComboPooledDATa Source构造方法创建数据源对象

package com.study.dao;

import com.mchange.v2.c3p0.ComboPooledDataSource;

import javax.sql.DataSource;
import java.beans.PropertyVetoException;
import java.sql.SQLException;

public class Example03 {
    public static DataSource dataSource=null;
    //初始化c3p0 数据源
    static {
        ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();

        try {
            comboPooledDataSource.setDriverClass("com.mysql.jdbc.Driver");
            comboPooledDataSource.setJdbcUrl("jdbc:mysql://localhost:3306/jdbc");
            comboPooledDataSource.setUser("root");
            comboPooledDataSource.setPassword("root");
            //设置连接池的参数
            comboPooledDataSource.setInitialPoolSize(5);
            comboPooledDataSource.setMaxPoolSize(15);
            dataSource=comboPooledDataSource;
        } catch (PropertyVetoException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws SQLException {
        System.out.println(dataSource.getConnection());
    }
}

通过读取配置文件创建数据源对象

<?xml version="1.0" encoding="UTF-8" ?>
<c3p0-config>
    <default-config>
        <property name="driverClass">
            com.mysql.jdbc.Driver
        </property>
        <property name="jdbcUrl">
            jdbc:mysql://localhost:3306/jdbc
        </property>
        <property name="user">root</property>
        <property name="password">root</property>
        <property name="checkoutTimeout">3000</property>
        <property name="initialPoolSize">10</property>
        <property name="maxIdleTime">30</property>
        <property name="maxPoolSize">100</property>
        <property name="minPoolSize">10</property>
        <property name="maxStatements">200</property>
    </default-config>
    <named-config name="teng">
        <property name="driverClass">
            com.mysql.jdbc.Driver
        </property>
        <property name="jdbcUrl">
            jdbc:mysql://localhost:3306/jdbc
        </property>
        <property name="user">root</property>
        <property name="password">root</property>
        <property name="initialPoolSize">5</property>
        <property name="maxPoolSize">15</property>
    </named-config>
</c3p0-config>

package com.study.dao;

import com.mchange.v2.c3p0.ComboPooledDataSource;

import javax.sql.DataSource;
import java.sql.SQLException;

public class Example04 {
    public static DataSource dataSource=null;
    static {
        //使用c3p0-config.xml配置文件中 的name-config 节点中name 属性的值
        ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource("teng");
        dataSource=comboPooledDataSource;
    }

    public static void main(String[] args) throws SQLException {
        System.out.println(dataSource.getConnection());
    }
}

MVC三层架构设计模式

实体类：

@Data
@NoArgsConstructor
@AllArgsConstructor
public class UserBean {
    private String name;
    private String password;
    private String email;
}

RegisterFormBean类：

package com.study.pojo;
import java.util.HashMap;
import java.util.Map;
public class RegisterFormBean {
    private String name;
    private String password;
    private String password2;
    private String email;
    private Map<String,String> errors=new HashMap<String, String>();

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }

    public String getPassword2() {
        return password2;
    }

    public void setPassword2(String password2) {
        this.password2 = password2;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }
    public boolean validate(){
        boolean flag=true;
        if (name==null||name.trim().equals("")){
            errors.put("name","请输入姓名.");
            flag=false;
        }

        if (password==null||password.trim().equals("")){
            errors.put("password","请输入密码.");
            flag=false;
        }else if (password.length()>12 || password.length()<6){
            errors.put("password","请输入6-12个字符");
            flag=false;
        }
        if (password!=null&&!password.equals(password2)){
            errors.put("password2","两次输入的密码不一致.");
            flag=false;
        }
        if (email==null||email.trim().equals("")){
            errors.put("email","请输入邮箱.");
            flag=false;
        }else if (!email.matches("([a-zA-Z]|[0-9])(\\w|\\-)+@[a-zA-Z0-9]+\\.([a-zA-Z]{2,4})$")){
            errors.put("email","邮箱格有误.");
            flag=false;
        }
        return flag;
    }
    //向 Map 集合 errors 中添加 错误信息
    public void setErrorMsg(String err,String errMsg){
        if ((err!=null)&&(errMsg!=null)){
            errors.put(err,errMsg);
        }
    }
    //获取errors集合
    public Map<String,String> getErrors(){
        return errors;
    }
}

创建工具类：

package com.study.Utils;
import com.study.pojo.UserBean;
import java.util.HashMap;
public class DBUtils {
    private static DBUtils instance=new DBUtils();
    private HashMap<String, UserBean> users=new HashMap<String, UserBean>();
    private DBUtils(){
        UserBean userBean = new UserBean();
        userBean.setName("Jack");
        userBean.setPassword("121212");
        userBean.setEmail("Ser0994@163.com");
        users.put("jack",userBean);
        UserBean userBean1 = new UserBean();
        userBean1.setName("Rose");
        userBean1.setPassword("22222");
        userBean1.setEmail("Ser0994@163.com");
        users.put("Rose",userBean1);}
    public static DBUtils getInstance(){return instance;}
    //获取数据库 (users)中的数据
    public UserBean getUser(String userName){
        return (UserBean) users.get(userName);
    }
    //向数据库(users)插入数据
    public boolean insertUser(UserBean userBean){
        if (userBean==null){return false;}
        String userName=userBean.getName();
        if (users.get(userName)!=null){return false;}
        users.put(userName,userBean);
        return true;
    }
}

Servlet类

package com.study.Servlet;
import com.study.Utils.DBUtils;
import com.study.pojo.RegisterFormBean;
import com.study.pojo.UserBean;
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("/ControllerServlet")
public class ControllerServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setHeader("Content-type","text/html;charset=utf-8");
        resp.setCharacterEncoding("utf-8");
        resp.setContentType("text/html;charset=utf-8");
        //获取用户注册时表单提交的参数信息
        String name = new String(req.getParameter("name").getBytes("ISO-8859-1"),"utf-8");
        System.out.println(name);
        String password = req.getParameter("password");
        String password2 = req.getParameter("password2");
        String email = req.getParameter("email");
        //将获取的参数封装到注册表单相关的registerFormbean类中
        RegisterFormBean registerFormBean = new RegisterFormBean();
        registerFormBean.setName(name);
        registerFormBean.setPassword(password);
        registerFormBean.setPassword2(password2);
        registerFormBean.setEmail(email);
        //验证参数填写是否符合要求，如果不符合，转发到 register.jsp重新填写
        if (!registerFormBean.validate()){
            req.setAttribute("formBean",registerFormBean);
            req.getRequestDispatcher(req.getContextPath()+"/jsp/register.jsp").forward(req,resp);
            return;
        }
        //参数复合要求,将参数封装到 User Bean
        UserBean userBean = new UserBean();
        userBean.setName(name);
        userBean.setPassword(password2);
        userBean.setEmail(email);
        //调用DBUtil 的insertUser(）方法 执行添加操作,并返回一个boolean 类型的标注
        boolean b = DBUtils.getInstance().insertUser(userBean);
        if (!b){
            req.setAttribute("DbMes",registerFormBean);
            req.setAttribute("formBean",registerFormBean);
            req.getRequestDispatcher(req.getContextPath()+"/jsp/register.jsp").forward(req,resp);
            return;
        }
        resp.getWriter().println("恭喜您注册成功,3秒钟后自动跳转");
        //将成功注册的用户信息添加到session中
        req.getSession().setAttribute("userBean",userBean);
        //注册成功后，3秒钟跳转到登录成功页面 loginsuccess.jsp中
        resp.setHeader("refresh","3,url=/jsp/loginSuccess.jsp");
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       doGet(req,resp);
    }
}

jsp页面：

<%--
  Created by IntelliJ IDEA.
  User: Teng
  Date: 2021/12/13
  Time: 15:02
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=utf-8" language="java" %>
<html>
<head>
    <title>用户注册</title>
    <link rel="shortcut icon" href="../static/1.png" />
    <style>
        h3{margin-left: 100px;}
        #outer{width: 750px;}
        span{color: #ff0000;}
        div{height: 20px;margin-bottom: 10px;}
        .ch{width: 80px;text-align: right;float: left;}
        .ip{width: 500px;float: left;}
        .ip>input{margin-right: 20px;}
        #bt{margin-left: 50px;}
        #bt>input{margin-right: 30px;}
    </style>
</head>
<body>
<form action="/ControllerServlet" method="post">
    <h3>用户注册</h3>
    <div id="outer">
        <div>
            <div class="ch">姓名:</div>
            <div class="ip">
                <input type="text" name="name" value="${formBean.name}">
                <span>${formBean.errors.name}${DBMes}</span></div></div><div>
            <div class="ch">密码:</div>
            <div class="ip">
                <input type="password" name="password">
                <span>${formBean.errors.password}</span></div></div>
        <div>
            <div class="ch">确认密码:</div>
            <div class="ip">
                <input type="password" name="password2">
                <span>${formBean.errors.password2}</span>
            </div>
        </div>
        <div>
            <div class="ch">邮箱:</div>
            <div class="ip">
                <input type="email" name="email" value="${formBean.email}">
                <span>${formBean.errors.email}</span>
            </div>
        </div>
        <div id="bt">
            <input type="reset" value="重置">
            <input type="submit" value="注册">
        </div>
    </div>
</form>
</body>
</html>

<%--
  Created by IntelliJ IDEA.
  User: Teng
  Date: 2021/12/13
  Time: 15:13
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=utf-8" language="java" %>
<html>
<head>
    <title>登录成功</title>
    <link rel="shortcut icon" href="../static/1.png" />
    <style>
        #main{
            width: 500px;
            height: auto;
        }
        #main div{
            width: 400px;
            height: auto;
        }
        ul{
            padding-top: 1px;
            padding-left: 1px;
            list-style: none;
        }
    </style>
</head>
<body>
<%
   if (session.getAttribute("userBean")==null){
%>
<jsp:forward page="register.jsp" />
<%
   return;
    }
%>
<div id="main">
    <div id="welcome">恭喜你，登陆成功</div>
    <hr/>
    <div>您的信息</div>
    <div>
        <ul>
            <li>您的姓名:${userBean.name}</li>
            <li>您的邮箱:${userBean.email}</li>
        </ul>
    </div>
</div>
</body>
</html>

el表达式和jstl：


<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<form action="">
    num1 : <input type="text" name="num1" /> <br/>
    num2 : <input type="text" name="num" /> <br/>
    num3 : <input type="text" name="num" /> <br/>
    <input type="submit" value="提交" /> &nbsp;&nbsp;
    <input type="submit" value="重置">
    <hr/>
    num1 :${param.num1} <br/>
    num2 :${paramValues.num[0]} <br/>
    num3 :${paramValues.num[1]} <br/>

</form>
</body>
</html>

JDBC

搭建数据库环境:

create database jdbc;
user jdbc;
create table user(
id int primary key auto_increment,
name varchar(40),
password varchar(40),
email varchar(60),
birthday date 

)

编写JDBC程序：

package com.study.dao;

import java.io.InputStream;
import java.sql.*;
import java.util.Properties;

public class Example01 {
    public static void main(String[] args) {
        Statement statement = null;
        ResultSet resultSet = null;
        Connection connection = null;
        try {
            //注册驱动
            Class.forName("com.mysql.jdbc.Driver");
            String url = "jdbc:mysql://localhost:3306/jdbc?useSSL=true&useUnicode=true&characterEncoding=utf-8";
            String username = "root";
            String password = "root";
            connection = DriverManager.getConnection(url, username, password);
            //通过Connection 获取statement对象
            statement = connection.createStatement();
            //实现statement对象执行sql语句
            String sql = "select * from users";
            resultSet = statement.executeQuery(sql);
            //操作ResultSet 结果集
            System.out.println("id | name  |password | email | birthday");
            while (resultSet.next()) {
                int id = resultSet.getInt("id");
                String name = resultSet.getString("name");
                String psw = resultSet.getString("password");
                String email = resultSet.getString("email");
                Date birthday = resultSet.getDate("birthday");
                System.out.println(id + " | " + name + " | " + psw + " | " + email + " | " + birthday);
            }

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (resultSet != null) {
                try {
                    resultSet.close();
                    resultSet = null;//如果释放失败，就GC回收
                } catch (SQLException throwables) {
                    throwables.printStackTrace();
                }
            }
            if (connection != null) {
                try {
                    connection.close();
                    connection = null;//如果释放失败，就GC回收
                } catch (SQLException throwables) {
                    throwables.printStackTrace();
                }
            }
        }
    }
}

插入：

package com.study.dao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;

public class Example02 {
    public static void main(String[] args) {
        Connection connection=null;
        PreparedStatement preparedStatement=null;

        try {
            Class.forName("com.mysql.jdbc.Driver");
            String url = "jdbc:mysql://localhost:3306/jdbc?useSSL=true&useUnicode=true&characterEncoding=utf-8";
            String username = "root";
            String password = "root";
            connection=DriverManager.getConnection(url,username,password);

            String sql="INSERT INTO users(NAME,PASSWORD,email,birthday) VALUES(?,?,?,?);";
            //预加载sql语句,防止sql注入
            preparedStatement=connection.prepareStatement(sql);
            preparedStatement.setString(1,"ooyys");
            preparedStatement.setString(2,"1122");
            preparedStatement.setString(3,"ESer0994@163.com");
            preparedStatement.setString(4,"2021-11-23");
            preparedStatement.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            if (preparedStatement != null) {
                try {
                    preparedStatement.close();
                    preparedStatement = null;//如果释放失败，就GC回收
                } catch (SQLException throwables) {
                    throwables.printStackTrace();
                }
            }
            if (connection != null) {
                try {
                    connection.close();
                    connection = null;//如果释放失败，就GC回收
                } catch (SQLException throwables) {
                    throwables.printStackTrace();
                }
            }
        }

    }
}

查询值：

package com.study.dao;

import javax.swing.plaf.nimbus.State;
import java.sql.*;

public class Example03 {
    public static void main(String[] args) {
        Connection connection=null;
        Statement statement=null;
        ResultSet resultSet=null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            String url = "jdbc:mysql://localhost:3306/jdbc?useSSL=true&useUnicode=true&characterEncoding=utf-8";
            String username = "root";
            String password = "root";
            //获取 Connection 对象
            connection= DriverManager.getConnection(url,username,password);
           //编写sql语句
            String sql="select * from users";
            //创建statement 对象并设置常量
            statement=connection.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
          //执行sql语句
             resultSet = statement.executeQuery(sql);
            System.out.println("第二条数据的name值为:");
            resultSet.absolute(2);//将指针定位到2
            System.out.println(resultSet.getString("name"));
            System.out.println("第一条数据的name值为:");
            resultSet.beforeFirst();//将指针定位到第一行之前
            resultSet.next();//将指针向红滚动
            System.out.println(resultSet.getString("name"));
            System.out.println("第四条数据的name值为:");
            resultSet.afterLast();//将指针定位到结果集中最后一条数据之后
            resultSet.previous();//将指针先前滚
            System.out.println(resultSet.getString("name"));

        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            if (statement != null) {
                try {
                    statement.close();
                    statement = null;//如果释放失败，就GC回收
                } catch (SQLException throwables) {
                    throwables.printStackTrace();
                }
            }
            if (connection != null) {
                try {
                    connection.close();
                    connection = null;//如果释放失败，就GC回收
                } catch (SQLException throwables) {
                    throwables.printStackTrace();
                }
            }
            if (resultSet != null) {
                try {
                    resultSet.close();
                    resultSet = null;//如果释放失败，就GC回收
                } catch (SQLException throwables) {
                    throwables.printStackTrace();
                }
            }
        }
    }
}