4.1 JdbcTemplate for declarative transactions

4、声明式事务

4.1、JdbcTemplate

4.1.1、简介

Spring 框架对 JDBC 进行封装,使用 JdbcTemplate 方便实现对数据库操作

4.1.2、准备工作

①加入依赖

<dependencies>
        <!-- 基于Maven依赖传递性,导入spring-context依赖即可导入当前所需所有jar包 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.3.1</version>
        </dependency>
        <!-- Spring 持久化层支持jar包 -->
        <!-- Spring 在执行持久化层操作、与持久化层技术进行整合过程中,需要使用orm、jdbc、tx三个
        jar包 -->
        <!-- 导入 orm 包就可以通过 Maven 的依赖传递性把其他两个也导入 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>5.3.1</version>
        </dependency>
        <!-- Spring 测试相关 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>5.3.1</version>
        </dependency>
        <!-- junit测试 -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <!-- MySQL驱动 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.29</version>
        </dependency>
        <!-- 数据源 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.31</version>
        </dependency>
    </dependencies>

②创建jdbc.properties

jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/ssm?serverTimezone=UTC
jdbc.username=root
jdbc.password=root

③配置Spring的配置文件

<!--引入jdbc.properties-->
    <context:property-placeholder location="classpath:jdbc.properties"></context:property-placeholder>

    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="${jdbc.driver}"></property>
        <property name="url" value="${jdbc.url}"></property>
        <property name="username" value="${jdbc.username}"></property>
        <property name="password" value="${jdbc.password}"></property>
    </bean>

    <bean class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"></property>
    </bean>

---

4.1.3、测试

①在测试类装配 JdbcTemplate

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:spring-jdbc.xml")
public class JDBCTemplateTest {
    
@Autowired
private JdbcTemplate jdbcTemplate;
}

@RunWith(SpringJUnit4ClassRunner.class)

Specifies that the current test class is inspringExecuted in the test environment,
At this point, it can be obtained directly by injectionioc容器的bean

@ContextConfiguration(“classpath:spring-jdbc.xml”)

设置spring测试环境的配置文件

②测试增删改功能

增删改都是update：

@Test
    public void jdbcInsert(){
    
        String sql = "insert into t_user values(null,?,?,?,?,?)";
        jdbcTemplate.update(sql,"root","3333",33,"女","[email protected]");
    }

③Query a piece of data as an entity class object

    @Test
    public void testGetUserById(){
    

        String sql = "select * from t_user where id = ?";
        User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<>(User.class), 2);
        System.out.println(user);

    }

④查询多条数据为一个list集合

    @Test
    public void testGetAllUser(){
    
        String sql = "select * from t_user";
        List<User> query = jdbcTemplate.query(sql, new BeanPropertyRowMapper<>(User.class));
        query.forEach(System.out::println);
    }

⑤Query the value of a single row and single column

    @Test
    public void testGetCount(){
    
        String sql = "select count(*) from t_user";
        Integer integer = jdbcTemplate.queryForObject(sql, Integer.class);
        System.out.println(integer);
    }