今天完成的事情：

• 使用JdbcTemplate连接数据库分离Interface和Imple

• 添加 Spring 依赖

• 在你的 pom.xml 文件中添加以下依赖

• <?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.example</groupId>
      <artifactId>Test3</artifactId>
      <version>1.0-SNAPSHOT</version>
      <build>
          <plugins>
              <plugin>
                  <groupId>org.apache.maven.plugins</groupId>
                  <artifactId>maven-compiler-plugin</artifactId>
                  <configuration>
                      <source>6</source>
                      <target>6</target>
                  </configuration>
              </plugin>
          </plugins>
      </build>
  
      <dependencies>
          <!-- Spring JDBC -->
          <dependency>
              <groupId>org.springframework</groupId>
              <artifactId>spring-jdbc</artifactId>
              <version>5.3.20</version>
          </dependency>
          <!-- MySQL Connector -->
          <dependency>
              <groupId>mysql</groupId>
              <artifactId>mysql-connector-java</artifactId>
              <version>8.0.26</version>
          </dependency>
          <!-- Spring Context for configuration -->
          <dependency>
              <groupId>org.springframework</groupId>
              <artifactId>spring-context</artifactId>
              <version>5.3.20</version>
          </dependency>
          <!-- https://mvnrepository.com/artifact/org.junit.jupiter/junit-jupiter-api -->
          <dependency>
              <groupId>org.junit.jupiter</groupId>
              <artifactId>junit-jupiter-api</artifactId>
              <version>5.12.0</version>
              <scope>test</scope>
          </dependency>
  
      </dependencies>
  
  </project>

  创建 DAO 接口

  创建一个名为 UserDao.java 的接口文件：

• package org.example;
  
  import java.util.List;
  
  public interface UserDao {
      void addUser(String name, int QQ);
      void updateUser(int id, String name, int QQ);
      void deleteUser(int id);
      List<String> queryAllUsers();

 实现 DAO 接口

创建一个名为 UserDaoImpl.java 的类文件，使用 JdbcTemplate 实现 UserDao 接口：

package org.example;

import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;

import javax.sql.DataSource;
import java.util.List;

@Repository
public class UserDaoImpl implements UserDao {

    private JdbcTemplate jdbcTemplate;

    @Autowired
    public void setDataSource(DataSource dataSource) {
        this.jdbcTemplate = new JdbcTemplate(dataSource);
    }

    @Override
    public void addUser(String name, int QQ) {
        String sql = "INSERT INTO ye (name, QQ) VALUES (?, ?)";
        jdbcTemplate.update(sql, name, QQ);
        System.out.println("用户已添加: " + name + ", QQ: " + QQ);
    }

    @Override
    public void updateUser(int id, String name, int QQ) {
        String sql = "UPDATE ye SET name = ?, QQ = ? WHERE id = ?";
        jdbcTemplate.update(sql, name, QQ, id);
        System.out.println("用户已更新: ID: " + id + ", Username: " + name + ", QQ: " + QQ);
    }

    @Override
    public void deleteUser(int id) {
        String sql = "DELETE FROM ye WHERE id = ?";
        jdbcTemplate.update(sql, id);
        System.out.println("用户已删除: ID: " + id);
    }

    @Override
    public List<String> queryAllUsers() {
        String sql = "SELECT * FROM ye";
        return jdbcTemplate.query(sql, new UserRowMapper());
    }

    private static class UserRowMapper implements RowMapper<String> {
        @Override
        public String mapRow(java.sql.ResultSet rs, int rowNum) throws java.sql.SQLException {
            int id = rs.getInt("id");
            String username = rs.getString("name");
            int QQ = rs.getInt("QQ");
            return "ID: " + id + ", Username: " + username + ", QQ: " + QQ;
        }
    }
}

配置数据源

创建一个 Spring 配置文件 applicationContext.xml 来配置数据源和 Bean

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

    <!-- 启用注解扫描 -->
    <context:component-scan base-package="org.example"/>

    <!-- 数据源配置 -->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/run?useSSL=false&amp;serverTimezone=UTC"/>
        <property name="username" value="root"/>
        <property name="password" value="199410"/>
    </bean>

    <!-- JdbcTemplate 配置 -->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"/>
    </bean>
</beans>

主程序

最后，修改 main 方法以从 Spring 上下文中获取 UserDao 实例：

package org.example;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import java.util.List;

public class MainApp {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserDao userDao = context.getBean(UserDao.class);

        // 调用addUser方法添加新用户
        userDao.addUser("newUsername", 12); // 自动分配ID

        // 更新用户信息
        userDao.updateUser(3, "updatedUsername", 98765);

        // 删除用户
        userDao.deleteUser(11);

        // 查询所有用户
        List<String> allUsers = userDao.queryAllUsers();
        for (String user : allUsers) {
            System.out.println(user);
        }
    }
}

明天计划的事：

学习Mybatis连接数据库

遇到的问题：

对代码的具体含义不了解

收获：

成功使用 jdbcTemplate连接数据库，并进行增减查改的操作以及junit测试，学习一些面向对象的基础知识。