Spring框架--Spring JDBC

Posted 2021-08-05 肖帆咪

Spring 是个一站式框架：Spring 自身也提供了控制层的 SpringMVC 和 持久层的 Spring JdbcTemplate。

以前我们的写法

package com.spring0.test;
import com.alibaba.druid.pool.DruidDataSource;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class JdbcUtil {

    public Connection getConnection() throws SQLException {
		// DriverManager.getConnection()
        DruidDataSource source = new DruidDataSource();
        source.setUrl("");
        source.setUsername("");
        source.setPassword("");
        source.setDriverClassName("");
        return source.getConnection();
    }
}

如今的高级写法

1.导入jar包的坐标

<!-- spring-jdbc -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-jdbc</artifactId>
    <version>5.2.2.RELEASE</version>
</dependency>
<!-- 阿里数据源 -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.1.10</version>
</dependency>

2.创建一个config.properties的配置文件

driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybatis_db?characterEncoding=utf8&serverTimezone=Asia/Shanghai
uname=root
password=root

3.创建一个db.xml配置文件用来读取文件

<?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
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd
">
    <!-- 读取属性文件   -->
    <context:property-placeholder location="config.properties"></context:property-placeholder>
    <bean id="dateSource" class="com.alibaba.druid.pool.DruidDataSource">
        <!--spring生成数据库连接管理对象-->
        <property name="driverClassName" value="${driver}"></property>
        <property name="url" value="${url}"></property>
        <property name="username" value="${uname}"></property>
        <property name="password" value="${password}"></property>
        <property name="initialSize" value="10"></property>
        <property name="minIdle" value="5"></property>
        <property name="maxActive" value="20"></property>
    </bean>

    <!--在配置文件中创建 JdbcTemplate-->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dateSource"></property>
    </bean>
</beans>

4.在spring.xml中导入db.xml

<?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
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd
">

    <!--  spring开启注解扫描  -->
    <context:component-scan base-package="com.spring0"></context:component-scan>

    <import resource="db.xml"></import>
</beans>

5.测试

JdbcTemplate 中常用的方法
execute：无返回值，可执行 ddl，增删改语句
update：执行新增、修改、删除语句；
queryForXXX：执行查询相关语句；

package com.spring0.dao;

import com.alibaba.druid.pool.DruidDataSource;
import com.spring0.bean.Dept;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.stereotype.Repository;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import java.util.Map;
@Repository
public class UserDao {

    @Autowired
    JdbcTemplate jdbcTemplate;
    public void save(){
        //DruidDataSource自动获得connection 连接池
        
        //jdbcTemplate默认使用事务提交,执行完立即提交
        jdbcTemplate.update("insert into dept(name)values ('1111')");
        int c= 10/0;
        jdbcTemplate.update("insert into dept(name)values ('2222')");
    }
}

现在我们大部分使用的是MyBatis,不在使用Spring自带的JdbcTemplate,这种方式也只做了解