JDBC数据库访问与JavaBean

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一、增加新学号功能实现

  1. 用户点击“添加新学号”链接，页面跳转到addNum.jsp页面，在该页面中输入学号和名字信息，点击确认按钮，跳转到doAddNum.jsp页面；

  1. doAddNum.jsp页面获取所输入的学号信息，使用JDBC将信息添加到数据表java2022；

  1. 添加完成跳转到showAllStudents.jsp页面。

//showAllStudents.jsp

<%@ page import="java.sql.*" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>显示所有学生信息</title>
</head>
<body>
<a href="addNum.jsp">添加学号</a>
<%
    //1.加载驱动程序
    Class.forName("com.mysql.jdbc.Driver");
    //2.建立与数据库的连接
    String url = "jdbc:mysql://localhost:3306/java2022";
    Connection conn = DriverManager.getConnection(url, "root", "root");
    //3.创建命令对象
    Statement st=conn.createStatement();
    //4.执行SQL语句
    String sql = "SELECT * FROM java2022";
    ResultSet rs=st.executeQuery(sql);
    //5.获取并输出查询结果
    out.println("<table border='1'>");
    out.println("<tr><td>学号num</td><td>姓名name</td>><td>编辑</td></tr>");
    while (rs.next())
        out.println("<tr>");
        out.println("<td>"+rs.getString("num")+"</td>");
        out.println("<td>"+rs.getString("name")+"</td>");
        out.println("<td>");
        out.println("<a href='updateNum.jsp?num="+rs.getString("num")+"'>修改</a>");
        out.println("<a href='deleteNum.jsp?num="+rs.getString("num")+"'>删除</a>");
        out.println("</td>");
        out.println("</tr>");
    
    out.println("</table>");
    //6.释放资源
    rs.close();    st.close();    conn.close();
%>
</body>
</html>

//addNum.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>添加新学号</title>
</head>
<body>
    <form action="doAddNum.jsp">
        学号：<input type="text" name="num">
        姓名：<input type="text" name="name">
        <input type="submit" value="提交">
    </form>
</body>
</html>

//doAddNum.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <%
        String num = request.getParameter("num");
        String name = request.getParameter("name");
        Class.forName("com.mysql.cj.jdbc.Driver");
        String url = "jdbc:mysql://localhost:3306/javaee";
        Connection conn = DriverManager.getConnection(url, "root", "123456");
        String sql = "insert into java2022(num,name) values(?,?)";
        PreparedStatement pst = conn.prepareStatement(sql);
        pst.setString(1, num);
        pst.setString(2, name);
        pst.executeUpdate();
        response.sendRedirect("showAllStudents.jsp");
        ps.close();
conn.close();

    %>
</body>
</html>

二、根据学号num修改学生名字name实现

1.用户点击“编辑”链接，跳转到updateName.jsp文件，在该页面中显示并可修改指定num的名字信息，点击提交按钮，跳转到doUpdateName.jsp文件；

2.doUpdateName.jsp文件获取updateName.jsp文件中所输入的名字，根据学号修改学生名字；

3.修改完成跳转到showAllStudents.jsp页面。

//updateName.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>修改</title>
</head>
<body>
    <%
        String num = request.getParameter("num");
    %>
    <form action="doUpdateName.jsp">
        学号：<input type="text" name="num" value="<%=num%>" readonly>
        姓名：<input type="text" name="name">
        <input type="submit" value="修改">
    </form>
</body>
</html>

//doUpdateName.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <%
        String num = request.getParameter("num");
        String name = request.getParameter("name");
        Class.forName("com.mysql.cj.jdbc.Driver");
        String url = "jdbc:mysql://localhost:3306/javaee";
        Connection conn = DriverManager.getConnection(url, "root", "123456");
        String sql = "update java2022 set name=? where num=?";
        PreparedStatement ps = conn.prepareStatement(sql);
        ps.setString(1, name);
        ps.setString(2, num);
        ps.executeUpdate();
        response.sendRedirect("showAllStudents.jsp");
        ps.close();
        conn.close();
    %>
</body>
</html>

三、根据学号num删除学生信息功能实现

1.用户点击“删除”链接，页面跳转到deleteNum.jsp文件，在该页面中获取学号num，根据学号num删除学生信息；

2.删除完成跳转到showAllStudents.jsp页面。

//deleteNum.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>删除学生信息</title>
</head>
<body>
    <%
        String num = request.getParameter("num");
        Class.forName("com.mysql.cj.jdbc.Driver");
        String url = "jdbc:mysql://localhost:3306/javaee";
        Connection conn = DriverManager.getConnection(url, "root", "123456");
        String sql = "delete from java2022 where num=?";
        PreparedStatement pst = conn.prepareStatement(sql);
        pst.setString(1, num);
        pst.executeUpdate();
        response.sendRedirect("showAllStudents.jsp");
    ps.close();
conn.close();
    
    %>
</body>
</html>

四、JavaBean的创建，能够使用“代码法”和“标签法”两种方式建立JavaBean实例对象、设置属性和获取属性：

1) 在src下的pojo包中创建JavaBean，文件名为Student.java，具体内容如下：

  • 成员变量：

num //学号，String类型，私有权限

name //姓名，String类型，私有权限

  • 成员方法：

每一个属性对应的getter和setter方法，均为公有权限

2) 新建立一个javabean.jsp页面，用“代码法”和“标签法”创建JavaBean实例，设置、获取属性。

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<jsp:useBean id="stu1" class="com.example.lab03.beans.Student">
    <jsp:setProperty name="stu1" property="num" value="0123"/>
    <jsp:setProperty name="stu1" property="name" value="张三"/>
    <jsp:getProperty name="stu1" property="num"/>
    <jsp:getProperty name="stu1" property="name"/>
</jsp:useBean>
<%
    Student stu2 = new Student();
    stu2.setNum("0456");
    stu2.setName("李四");
    out.print("<br>" + stu2.getNum() + stu2.getName());
%>
</body>
</html>

myBatis 基于javaBean配置

 

MyBatis的持久化解决方案是将用户从原始的JDBC访问中解放出来,用户只需要定义需要操作的SQL语句,

无须关注底层的JDBC操作,就可以以面向对象的方式来进行持久化层操作.底层数据库连接的获取,数据访问的实现,事务控制等都无须用户关心,

从而将应用层从底层的JDBC/JTA API抽取出来.通过配置文件管理JDBC连接,让MyBatis解决持久化的实现.在MyBatis中的常见对象有SqlSessionFactory和SqlSession.

 

 

依赖

 

技术图片 
 <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.0.1</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
            <version>5.1.27</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.10</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
            </resource>
        </resources>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
View Code

 

技术图片

use类

技术图片 
public class User 
    private Long id;
    private String username;
    private String address;

    @Override
    public String toString() 
        return "User" +
                "id=" + id +
                ", username=‘" + username + ‘\\‘‘ +
                ", address=‘" + address + ‘\\‘‘ +
                ‘‘;
    

    public Long getId() 
        return id;
    

    public void setId(Long id) 
        this.id = id;
    

    public String getUsername() 
        return username;
    

    public void setUsername(String username) 
        this.username = username;
    

    public String getAddress() 
        return address;
    

    public void setAddress(String address) 
        this.address = address;
View Code

DataSourceConfig 数据源配置类
技术图片 
import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;


@Configuration
public class DataSourceConfig 
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.one")
    DataSource dsOne() 
        return DruidDataSourceBuilder.create().build();
    

    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.two")
    DataSource dsTwo() 
        return DruidDataSourceBuilder.create().build();
View Code

 

MyBatisConfigOne
技术图片 
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;


@Configuration
@MapperScan(basePackages = "org.javaboy.mybatis.mapper1", sqlSessionFactoryRef = "sqlSessionFactory1", sqlSessionTemplateRef = "sqlSessionTemplate1")
public class MyBatisConfigOne 
    @Autowired
    @Qualifier("dsOne")
    DataSource dsOne;
    @Bean
    SqlSessionFactory sqlSessionFactory1() 
        SqlSessionFactory sessionFactory = null;
        try 
            SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
            bean.setDataSource(dsOne);
            sessionFactory = bean.getObject();
         catch (Exception e) 
            e.printStackTrace();
        
        return sessionFactory;
    
    @Bean
    SqlSessionTemplate sqlSessionTemplate1() 
        return new SqlSessionTemplate(sqlSessionFactory1());
View Code
MyBatisConfigTwo
技术图片 
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;


@Configuration
@MapperScan(basePackages = "org.javaboy.mybatis.mapper2", sqlSessionFactoryRef = "sqlSessionFactory2", sqlSessionTemplateRef = "sqlSessionTemplate2")
public class MyBatisConfigTwo 
    @Autowired
    @Qualifier("dsTwo")
    DataSource dsOne;
    @Bean
    SqlSessionFactory sqlSessionFactory2() 
        SqlSessionFactory sessionFactory = null;
        try 
            SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
            bean.setDataSource(dsOne);
            sessionFactory = bean.getObject();
         catch (Exception e) 
            e.printStackTrace();
        
        return sessionFactory;
    
    @Bean
    SqlSessionTemplate sqlSessionTemplate2() 
        return new SqlSessionTemplate(sqlSessionFactory2());
View Code
UserMapper1
技术图片 
import org.javaboy.mybatis.bean.User;

import java.util.List;


//@Mapper
public interface UserMapper1 
//    @Select("select * from t_user")
    List<User> getAllUser();
View Code
UserMapper1.xml
技术图片 
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="org.javaboy.mybatis.mapper1.UserMapper1">
    <select id="getAllUser" resultType="org.javaboy.mybatis.bean.User">
        select * from t_user;
    </select>
</mapper>
View Code

UserMapper2
技术图片 
import org.javaboy.mybatis.bean.User;

import java.util.List;


//@Mapper
public interface UserMapper2
//    @Select("select * from t_user")
    List<User> getAllUser();
View Code
UserMapper2.xml
技术图片 
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="org.javaboy.mybatis.mapper2.UserMapper2">
    <select id="getAllUser" resultType="org.javaboy.mybatis.bean.User">
        select * from t_user;
    </select>
</mapper>
View Code

application.properties 配置文件

技术图片 
spring.datasource.one.url=jdbc:mysql:///test01
spring.datasource.one.username=root
spring.datasource.one.password=root
spring.datasource.one.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.one.driver-class-name=com.mysql.jdbc.Driver

spring.datasource.two.url=jdbc:mysql:///test02
spring.datasource.two.username=root
spring.datasource.two.password=root
spring.datasource.two.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.two.driver-class-name=com.mysql.jdbc.Driver
View Code

 



 
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