13、Spring之JdbcTemplate

13.1、環境搭建

13.1.1、創建module

13.1.2、選擇maven

13.1.3、設置module名稱和路徑

13.1.4、module初始狀態

13.1.5、配置打包方式和依賴

<?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相關 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.3.1</version>
        </dependency>

        <!-- Spring 持久化層相關 -->
        <!-- Spring 在執行持久化層操作、與持久化層技術進行整合過程中，需要使用orm、jdbc、tx三個jar包 -->
        <!-- 導入 orm 包就可以通過 Maven 的依賴傳遞性把其他兩個也導入 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>5.3.1</version>
        </dependency>

        <!-- Spring 測試相關 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>5.3.1</version>
        </dependency>

        <!-- junit測試 -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>

        <!-- MySQL驅動 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.49</version>
        </dependency>

        <!-- 數據源 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.31</version>
        </dependency>
    </dependencies>

</project>

13.1.6、創建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、創建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">

    <!-- 導入外部屬性文件 -->
    <context:property-placeholder location="jdbc.properties"></context:property-placeholder>

    <!-- 配置數據源 -->
    <bean id="datasource" class="com.alibaba.druid.pool.DruidDataSource">
        <!--通過${key}的方式訪問外部屬性文件的value-->
        <property name="driverClassName" value="${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">
        <!-- 裝配數據源 -->
        <property name="dataSource" ref="datasource"></property>
    </bean>

</beans>

13.2、Spring整合Junit4單元測試

13.2.1、創建測試類

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註解：表示使用 SpringJUnit4ClassRunner 運行器來運行測試方法
    // 這樣測試類便在Spring的測試環境中執行，此時就可以通過註入的方式直接獲取IOC容器中的bean
@RunWith(SpringJUnit4ClassRunner.class)
// @ContextConfiguration註解：用來指定載入ApplicationContext的配置文件或配置類
@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","[email protected]");
    }

}

13.2.2、執行測試方法

++++++++++++++++++++++++++++++分割線++++++++++++++++++++++++++++++

JdbcTemplate的增刪改都是用update這個方法

++++++++++++++++++++++++++++++分割線++++++++++++++++++++++++++++++

13.3、JdbcTemplate的查詢功能

13.3.1、創建實體類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、查詢單條數據

    @Test
    public void testGetUserById(){
        String sql = "select * from t_user where id = ?";
        // 第一個參數是設置要執行的sql語句，第二個參數是設置查詢結果和實體類的對應關係，後面的參數列表是設置sql語句中占位符的值
        User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), 10);
        System.out.println(user);
    }

13.3.3、查詢多條數據

    @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、查詢單行單列

    @Test
    public void testUserCount(){
        String sql = "select count(*) from t_user";
        // 第二個參數是設置查詢結果對應的Java類型；如果sql中有占位符，後面可以用參數列表來設置sql語句中占位符的值
        Integer integer = jdbcTemplate.queryForObject(sql, Integer.class);
        System.out.println("用戶數量為："+integer);
    }