在传统方法中，我们一般建立 Connection 链接，然后通过 **Statement stm = conn.createStatement()**来获取 Statement 对象，最后用 Statement 对象操作数据库。
在 spring 中，则是通过 com.alibaba 的 druid配置数据源工具，来配置要连接的数据库，然后将配置好的数据源作为属性传入 JDBCTemplate 对象当中，最后用 JDBCTemplate 对象操作数据库。
一、pom 文件所需依赖
\<dependency\>
\<!--jar包依赖--\>
\<groupId\>org.springframework\</groupId\>
\<artifactId\>spring-jdbc\</artifactId\>
\<version\>6.0.2\</version\>
\</dependency\>
\<dependency\>
\<!--MySQL驱动--\>
\<groupId\>mysql\</groupId\>
\<artifactId\>mysql-connector-java\</artifactId\>
\<version\>8.0.30\</version\>
\</dependency\>
\<dependency\>
\<!--数据源工具--\>
\<groupId\>com.alibaba\</groupId\>
\<artifactId\>druid\</artifactId\>
\<version\>1.0.31\</version\>
\</dependency\>二、spring-config.xml 文件配置
XML
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<!--扫描组件-->
<context:component-scan base-package="com.mysql.conn"></context:component-scan>
<!--引入外部文件-->
<context:property-placeholder location="classpath:jdbc.properties"></context:property-placeholder>
<!--使用druid工具配置数据源-->
<bean id="druidDataSource" class="com.alibaba.druid.pool.DruidDataSource">
<property name="url" value="${jdbc.url}"></property>
<property name="driverClassName" value="${jdbc.driver}"></property>
<property name="username" value="${jdbc.user}"></property>
<property name="password" value="${jdbc.password}"></property>
</bean>
<!--将数据源作为属性传入JDBCTemplate对象-->
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="druidDataSource"></property>
</bean>
</beans>三、java 代码
java
package com.mysql.conn;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
//使用spring整合junit5进行测试
@SpringJUnitConfig(locations = "classpath:bean-jdbc.xml")
public class TestUpdate {
@Autowired
public JdbcTemplate jdbcTemplate;
@Test
public void testUpdate() {
String sql ="insert into user values(?,?,?)";
int rows = jdbcTemplate.update(sql,11,"lucy","30");
System.out.println(rows);
}
}四、常用 sql 语句
（一）增加
java
String sql ="insert into user values(?,?,?)";
Object[] x={11,"lucy","30"};
int rows = jdbcTemplate.update(sql,x);
System.out.println(rows);（二）删除
java
String sql ="delete from user where id = ? ";
int rows = jdbcTemplate.update(sql,10);
System.out.println(rows);（三）更改
java
String sql ="update user set account=?,password=? where id=?";
int rows = jdbcTemplate.update(sql,"James",123,8);
System.out.println(rows);（四）查询
1、查询单个对象
① 创建对象类
java
package com.mysql.conn;
public class User {
private int id;
private String account;
private String password;
//生成set方法，这一步很关键
public void setId(int id) {
this.id = id;
}
public void setAccount(String account) {
this.account = account;
}
public void setPassword(String password) {
this.password = password;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", account='" + account + '\'' +
", password='" + password + '\'' +
'}';
}
}② 测试类
java
package com.mysql.conn;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
@SpringJUnitConfig(locations = "classpath:bean-jdbc.xml")
public class TestUpdate {
@Autowired
public JdbcTemplate jdbcTemplate;
@Test
public void testUpdate() {
String sql ="select * from user where id = ?";
//第一种写法
User user1 = jdbcTemplate.queryForObject(sql,new BeanPropertyRowMapper<>(User.class),1);
System.out.println(user1);
//第二种写法
User user2 = jdbcTemplate.queryForObject(sql,
(rs, rowNum) -> {
User user = new User();
user.setId(rs.getInt("id"));
user.setAccount(rs.getString("account"));
user.setPassword(rs.getString("password"));
return user;
}, 2);
System.out.println(user2);
}
}2、查询 list 集合
① 目标类不变
② 测试类
java
package com.mysql.conn;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
import java.util.List;
@SpringJUnitConfig(locations = "classpath:bean-jdbc.xml")
public class TestUpdate {
@Autowired
public JdbcTemplate jdbcTemplate;
@Test
public void testUpdate() {
String sql ="select * from user";
List<User> list = jdbcTemplate.query(sql, new BeanPropertyRowMapper<>(User.class));
System.out.println(list);
}
}3、查询单个值
测试类（查询多少行）
java
package com.mysql.conn;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
@SpringJUnitConfig(locations = "classpath:bean-jdbc.xml")
public class TestUpdate {
@Autowired
public JdbcTemplate jdbcTemplate;
@Test
public void testUpdate() {
String sql ="select count(account) from user";
Integer i = jdbcTemplate.queryForObject(sql, Integer.class);
System.out.println(i);
}
}