Spring框架对JDBC进行封装，使用JdbcTemplate方便对数据库操作。

1.搭建模块

2.引入依赖

    <dependencies>

<!--        spring jdba Spring持久化层支持jar包-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>6.0.2</version>
        </dependency>
<!--        Mysql驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.33</version>
        </dependency>
<!--        数据源-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.2.15</version>
        </dependency>
    </dependencies>

3.创建配置文件

jdbc.properties

jdbc.user=root
jdbc.password=Mitaowulong
jdbc.url=jdbc:mysql://localhost:3306/yogurt
jdbc.driver=com.mysql.cj.jdbc.Driver

bean.xml

<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">
    
<!--    引入外部属性文件，创建数据源对象-->
    <context:property-placeholder location="classpath:jdbc.properties"></context:property-placeholder>
    
    <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>
<!--    创建jdbcTemplate对象，注入数据-->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="druidDataSource"></property>
    </bean>
    
</beans>

4. 创建数据库

create table t_emp(
id int not null auto_increment,
name varchar(20) default null comment "姓名",
age int(11) default null comment "年龄",
sex varchar(2) default null comment "性别",
primary key(id))engine=innodb default charset=utf8mb4

5.创建测试类

package com.yogurt.spring6.jdbc;


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;

/**
 * ClassName: JdbcTemplateTest
 * Package: IntelliJ IDEA
 * Description:
 *
 * @Author 半生瓜
 * @Create 2023/11/8 22:17
 * @Version 1.0
 */
@SpringJUnitConfig(locations = "classpath:bean.xml")
public class JdbcTemplateTest {

    @Autowired
    private JdbcTemplate jdbcTemplate;
    
    @Test
    public void testUpdate(){

    }
}

6.使用JdbaTemplate实现对数据的CRUD

添加、修改、删除

//添加 修改 删除

   @Test
    public void testUpdate(){
       /*
       //1.添加操作
       //第一步 编写sql语句
       String sql = "insert into t_emp values(null,?,?,?)";
       //调用jdbcTemplate的方法，传入相关参数
//        Object[] params = {"李一", 20, "未知"};
//        int rows = jdbcTemplate.update(sql,params);
       int rows = jdbcTemplate.update(sql,"李三", 18, "女");
       System.out.println(rows);
       */

       /*
       //修改操作
       String sql = "update t_emp set name = ? where id = ?";
       int rows = jdbcTemplate.update(sql, "周一", 2);
       System.out.println(rows);
        */

       //删除操作
       String sql = "delete from t_emp where id = ?";
       int rows = jdbcTemplate.update(sql, 2);
       System.out.println(rows);
   }

 查询

1.建实体类

public class Emp {
    private Integer id;
    private String name;
    private Integer age;
    private String sex;

    @Override
    public String toString() {
        return "Emp{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", sex='" + sex + '\'' +
                '}';
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }
}

2.测试

@SpringJUnitConfig(locations = "classpath:bean.xml")
public class JdbcTemplateTest {

    @Autowired
    private JdbcTemplate jdbcTemplate;

    //查询：返回对象
    @Test
    public void testSelectObject(){
        //写法一（自己封装）
//        String sql = "select * from t_emp where id = ?";
//        Emp empResult = jdbcTemplate.queryForObject(sql,
//                (rs,rowNum)->{
//            Emp emp = new Emp();
//            emp.setId(rs.getInt("id"));
//            emp.setName(rs.getString("name"));
//            emp.setAge(rs.getInt("age"));
//            emp.setSex(rs.getString("sex"));
//                return emp;
//        },1);
//        System.out.println(empResult);

        //写法二（用接口）
        String sql = "select * from t_emp where id = ?";
        Emp emp = jdbcTemplate.queryForObject(sql,new BeanPropertyRowMapper<>(Emp.class),1);
        System.out.println(emp);

    }

    //查询：返回list集合
    @Test
    public void testSelectList(){
        String sql = "select * from t_emp";
        List<Emp> list = jdbcTemplate.query(sql, new BeanPropertyRowMapper<>(Emp.class));
        System.out.println(list);
    }

    //查询：返回表中记录数
    @Test
    public void testSelectValue(){
        String sql = "select count(*) from t_emp";
        Integer count = jdbcTemplate.queryForObject(sql, Integer.class);
        System.out.println(count);
    }