13、Spring之JdbcTemplate

13.1、环境搭建

13.1.1、创建module

13.1.2、选择maven

13.1.3、设置module名称和路径

13.1.4、module初始状态

13.1.5、配置打包方式和依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.rain</groupId>
    <artifactId>spring_jdbcTemplate</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <dependencies>

        <!-- Spring IOC相关 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.3.1</version>
        </dependency>

        <!-- Spring 持久化层相关 -->
        <!-- 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>5.1.49</version>
        </dependency>

        <!-- 数据源 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.31</version>
        </dependency>
    </dependencies>

</project>

13.1.6、创建jdbc.properties文件

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/ssm?characterEncoding=utf-8
jdbc.username=root
jdbc.password=root

13.1.7、创建Spring的配置文件

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

    <!-- 导入外部属性文件 -->
    <context:property-placeholder location="jdbc.properties"></context:property-placeholder>

    <!-- 配置数据源 -->
    <bean id="datasource" class="com.alibaba.druid.pool.DruidDataSource">
        <!--通过${key}的方式访问外部属性文件的value-->
        <property name="driverClassName" value="${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>

    <!-- 配置 JdbcTemplate -->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <!-- 装配数据源 -->
        <property name="dataSource" ref="datasource"></property>
    </bean>

</beans>

13.2、Spring整合Junit4单元测试

13.2.1、创建测试类

package org.rain.spring.test;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

/**
 * @author liaojy
 * @date 2023/8/22 - 7:43
 */

// @RunWith注解：表示使用 SpringJUnit4ClassRunner 运行器来运行测试方法
    // 这样测试类便在Spring的测试环境中执行，此时就可以通过注入的方式直接获取IOC容器中的bean
@RunWith(SpringJUnit4ClassRunner.class)
// @ContextConfiguration注解：用来指定加载ApplicationContext的配置文件或配置类
@ContextConfiguration("classpath:spring-jdbc.xml")
public class JdbcTemplateTest {

    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Test
    public void testInsert(){
        String sql = "insert into t_user values(null,?,?,?,?,?)";
        jdbcTemplate.update(sql,"jdbcTemplate","123",23,"男","123@qq.com");
    }

}

13.2.2、执行测试方法

++++++++++++++++++++++++++++++分割线++++++++++++++++++++++++++++++

JdbcTemplate的增删改都是用update这个方法

++++++++++++++++++++++++++++++分割线++++++++++++++++++++++++++++++

13.3、JdbcTemplate的查询功能

13.3.1、创建实体类User

package org.rain.spring.pojo;

/**
 * @author liaojy
 * @date 2023/8/22 - 8:12
 */
public class User {

    private Integer id;

    private String username;

    private String password;

    private Integer age;

    private String gender;

    private String email;

    public User(Integer id, String username, String password, Integer age, String gender, String email) {
        this.id = id;
        this.username = username;
        this.password = password;
        this.age = age;
        this.gender = gender;
        this.email = email;
    }

    public User() {
    }

    public Integer getId() {
        return id;
    }

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

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public Integer getAge() {
        return age;
    }

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

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", age=" + age +
                ", gender='" + gender + '\'' +
                ", email='" + email + '\'' +
                '}';
    }
}

13.3.2、查询单条数据

    @Test
    public void testGetUserById(){
        String sql = "select * from t_user where id = ?";
        // 第一个参数是设置要执行的sql语句，第二个参数是设置查询结果和实体类的对应关系，后面的参数列表是设置sql语句中占位符的值
        User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), 10);
        System.out.println(user);
    }

13.3.3、查询多条数据

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

13.3.4、查询单行单列

    @Test
    public void testUserCount(){
        String sql = "select count(*) from t_user";
        // 第二个参数是设置查询结果对应的Java类型；如果sql中有占位符，后面可以用参数列表来设置sql语句中占位符的值
        Integer integer = jdbcTemplate.queryForObject(sql, Integer.class);
        System.out.println("用户数量为："+integer);
    }