Spring JDBC环境配置

有Mybatis为什么还需要Spring JDBC？

 

　MyBatis作为ORM框架，封装程度高，适合中小企业进行软件的敏捷开发，让程序员快速的完成数据交互工作，但是MyBatis涉及到一系列xml的配置以及各种操作细节，封装程度高，执行效率低。Spring JDBC只是对原始JDBC的API简单封装，当数据量、用户并发量极高时，如果使用MyBatis，一些微小的性能差距就会导致整体应用变慢，一线大厂更青睐Spring JDBC轻量级的封装框架，在此基础上结合自己的企业特点进行二次封装。Spring JDBC执行效率要高于MyBatis，Spring JDBC是介于ORM框架和原生JDBC的折中选择

 

Spring JDBC环境配置

　1.Maven工厂引入依赖

<dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>5.3.17</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>5.3.17</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.49</version>
    </dependency>
</dependencies>

　2.在applicationContext.xml中配置DataSource数据源和JdbcTemplate对象

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd">
    <!--数据源-->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="url"
                  value="jdbc:mysql://localhost:3306/imooc?useSSL=false&amp;useUnicode=true&amp;
                  characterEncoding=UTF-8&amp;serverTimezone=Asia/Shanghai&amp;allowPublicKeyRetrieval=true"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
    </bean>
    <!--jdbcTemplate提供了数据库CRUD的API-->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"/>
    </bean>
</beans>

　3.新建一个实体类，属性对应数据库字段

package com.spring.jdbc.entity;

import java.util.Date;

public class Employee {
    private Integer eno;
    private String ename;
    private Float salary;
    private String dname;
    private Date hiredate;

    public Integer getEno() {
        return eno;
    }

    public void setEno(Integer eno) {
        this.eno = eno;
    }

    public String getEname() {
        return ename;
    }

    public void setEname(String ename) {
        this.ename = ename;
    }

    public Float getSalary() {
        return salary;
    }

    public void setSalary(Float salary) {
        this.salary = salary;
    }

    public String getDname() {
        return dname;
    }

    public void setDname(String dname) {
        this.dname = dname;
    }

    public Date getHiredate() {
        return hiredate;
    }

    public void setHiredate(Date hiredate) {
        this.hiredate = hiredate;
    }

    @Override
    public String toString() {
        return "Employee{" +
                "eno=" + eno +
                ", ename='" + ename + '\'' +
                ", salary=" + salary +
                ", dname='" + dname + '\'' +
                ", hiredate=" + hiredate +
                '}';
    }
}

　4.新建dao类，持有JdbcTemplate对象

package com.spring.jdbc.dao;

import com.spring.jdbc.entity.Employee;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

public class EmployeeDao {
    private JdbcTemplate jdbcTemplate;

    public Employee findById(Integer eno){
        String sql = "select * from employee where eno = ?";
        Employee employee = jdbcTemplate.queryForObject(sql,new Object[]{eno},new BeanPropertyRowMapper<Employee>(Employee.class));
        return employee;
    }
    public JdbcTemplate getJdbcTemplate() {
        return jdbcTemplate;
    }

    public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
        this.jdbcTemplate = jdbcTemplate;
    }
}

　5.在ioc容器中配置EmployeeDao，为Dao注入JdbcTemplate对象，实现CRUD

<bean id="employeeDao" class="com.spring.jdbc.dao.EmployeeDao">
    <!--为Dao注入Template对象-->
    <property name="jdbcTemplate" ref="jdbcTemplate"/>
</bean>

　6.测试

package com.spring.jdbc;

import com.spring.jdbc.dao.EmployeeDao;
import com.spring.jdbc.entity.Employee;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class SpringApplication {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");
        EmployeeDao employeeDao = context.getBean("employeeDao", EmployeeDao.class);
        Employee employee = employeeDao.findById(3308);
        System.out.println(employee);
    }
}