基于Spring注解 + MyBatis + Servlet 实现数据库交换的小小Demo

第一步 创建web 项目，这一步省略，有不会的可以参考之前发布的文档

第二步 配置pom.xml文件

<dependencies>
    <!-- Spring常用依赖 -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.2.9.RELEASE</version>
    </dependency>

    <!--aop相关-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aspects</artifactId>
      <version>5.2.9.RELEASE</version>
    </dependency>


    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
    </dependency>

    <!--注解-->
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>1.18.12</version>
    </dependency>

	 <!-- Mysq连接 -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.18</version>
    </dependency>
    <!--MyBatis核心依赖-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.4.6</version>
    </dependency>

    <!-- spring-jdbc -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>5.2.9.RELEASE</version>
    </dependency>

    <!-- spring+mybatis集成依赖 -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>1.3.2</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.1.16</version>
    </dependency>


    <!--整合一下 web-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>5.2.9.RELEASE</version>
    </dependency>
 <!-- servlet服务 -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>jsp-api</artifactId>
      <version>2.0</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>

    <!--logback 日志-->
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
      <version>1.7.25</version>
    </dependency>

    <dependency>
      <groupId>ch.qos.logback</groupId>
      <artifactId>logback-core</artifactId>
      <version>1.2.3</version>
    </dependency>

    <dependency>
      <groupId>ch.qos.logback</groupId>
      <artifactId>logback-classic</artifactId>
      <version>1.2.3</version>
    </dependency>
 <!--log4j 日志-->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>1.2.17</version>
    </dependency>

    <dependency>
      <groupId>org.logback-extensions</groupId>
      <artifactId>logback-ext-spring</artifactId>
      <version>0.1.4</version>
    </dependency>
  </dependencies>

<!--下面这一步配置到build标签里-->
<resources>
      <resource>
        <directory>src/main/java</directory>
        <includes>
        <include>**/*.xml</include>
      	</includes>
	</resource>
    
	<resource>
     <directory>src/main/resources</directory>
      <includes>
          <include>**/*.xml</include>
          <include>**/*.properties</include>
          <include>**/*.ini</include>
      </includes>
    </resource>
 </resources>

配置数据库连接信息 db.properties

jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/ssm?characterEncoding=utf8&useSSL=false&serverTimezone=Asia/Shanghai&rewriteBatchedStatements=true
jdbc.username=root
jdbc.password=123456

配置web.xml

<!-- 配置日志 logback -->
<context-param>
    <param-name>logbackConfigLocation</param-name>
    <param-value>classpath:logback.xml</param-value>
  </context-param>
  <listener>
    <listener-class>ch.qos.logback.ext.spring.web.LogbackConfigListener</listener-class>
  </listener>
  <!--这个监听器  帮助加载spring 配置文件，创建spring 容器-->
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:applicationContext.xml</param-value>
  </context-param>

配置logback.xml配置文件

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <appender name="stdout" class="ch.qos.logback.core.ConsoleAppender">
        <Target>System.out</Target>
        <Encoding>UTF-8</Encoding>
        <encoder>
            <pattern>%d{yyyy-MM-dd_HH:mm:ss.SSS} %5p [%t] [%c{1}]:%L - %m%n
            </pattern>
        </encoder>
    </appender>
    <appender name="logfile"
              class="ch.qos.logback.core.rolling.RollingFileAppender">
        <Encoding>UTF-8</Encoding>
        <encoder>
            <pattern>%d %p [%t] [%c]:%L - %m%n</pattern>
        </encoder>
        <filter class="ch.qos.logback.classic.filter.ThresholdFilter">
            <level>DEBUG</level>
        </filter>
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <fileNamePattern>log/%d{yyyy-MM-dd-HH'.log'}</fileNamePattern>
        </rollingPolicy>
    </appender>
    <logger name="org.springframework" level="WARN" />
    <logger name="org.springframework.remoting" level="WARN" />
    <logger name="org.springframework.scheduling.quartz" level="WARN" />
    <logger name="org.springframework.data.jpa" level="DEBUG" />
    <logger name="org.cometd" level="WARN" />
    <logger name="ch.qos.logback" level="WARN" />
    <logger name="com.springapp.mvc" level="DEBUG" />
<!--  指定到mapper包  -->
    <logger name="com.hui.mapper" level="DEBUG"></logger>

    <root level="ERROR">
        <appender-ref ref="stdout" />
        <appender-ref ref="logfile" />
    </root>
</configuration>

配置applicationContext.xml 里面的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:aop="http://www.springframework.org/schema/aop"
       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/aop
        http://www.springframework.org/schema/aop/spring-aop.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">

    <!--基于注解的形式 管理 bean-->
    <!--扫描 com.hui下的全部组件-->
    <context:component-scan base-package="com.hui"></context:component-scan>

    <!--掌握   基于 AspectJ 的 注解 的  AOP实现 配置-->
    <aop:aspectj-autoproxy></aop:aspectj-autoproxy>

    <!--配置文件参数化（参数占位符）-->
    <context:property-placeholder location="classpath:db.properties" />

    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
        <!--Mysql 连接的 基本配置-->
        <property name="driverClassName" value="${jdbc.driver}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>

        <!-- 配置获取连接等待超时的时间 -->
        <property name="maxWait" value="60000"/>

        <!-- 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 -->
        <property name="timeBetweenEvictionRunsMillis" value="60000"/>

        <!-- 配置一个连接在池中最小生存的时间，单位是毫秒 -->
        <property name="minEvictableIdleTimeMillis" value="300000"/>
    </bean>

    <!-- 工厂bean：生成SqlSessionFactory -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!--数据源属性-->
        <property name="dataSource" ref="dataSource"></property>
        <!--mybatis的配置文件-->
        <property name="configLocation" value="classpath:mybatis-config.xml"></property>
    </bean>

    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!--扫描mapper 接口  自动创建mapper层代理对象  交给spring管理-->
        <property name="basePackage" value="com.hui.mapper"></property>

        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
    </bean>

</beans>

配置myBatis核心配置文件mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <typeAliases>
        <!--自动扫描包，将原类名作为别名-->
        <package name="com.hui.pojo" />
    </typeAliases>
    <mappers>
        <!--扫描resources xml  映射文件-->
        <package name="com.hui.mapper"/>
    </mappers>
</configuration>

创建实体类对象User

/**
 * @author 二手Java程序员
 * @since 2023/4/23 19:25
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
    private Integer id;
    private String name;
    private String password;
    private String sex;
    private Date birthday;
    private Date registTime;
}

创建LoginServlet响应前端的数据

/**
 * @author 二手Java程序员
 * @since 2023/4/23 19:29
 */
@WebServlet("/login") // 注解指定服务访问地址
public class LoginServlet extends HttpServlet {
    private UserService userService;

    @Override
    public void init() throws ServletException {
        //但是 这里 我们又想拿到 spring管理的bean 所以 采用下面这种方式
        WebApplicationContext applicationContext = WebApplicationContextUtils.getRequiredWebApplicationContext(getServletContext());

        userService = applicationContext.getBean("userService", UserService.class);
    }
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        System.out.println(username);
        System.out.println(password);
        User user = new User();
        user.setName(username);
        user.setPassword(password);
        System.out.println(user);
        User result = userService.login(user);
        System.out.println(result);
    }
}

创建UserService 接口

/**
 * @author 二手Java程序员
 * @since 2023/4/23 19:27
 */
public interface UserService {
    User login(User user);
}

创建UserMapper接口

/**
 * @author 二手Java程序员
 * @since 2023/4/23 19:30
 */
public interface UserMapper {
    User login(User user);
}

创建UserServiceImpl 接口实现类

/**
 * @author 二手Java程序员
 * @since 2023/4/23 19:28
 */
@Service("userService")
public class UserServiceImpl implements UserService {
    @Autowired
    private UserMapper userMapper;
    @Override
    public User login(User user) {
        System.out.println("UserServiceImpl"+ user);
        return userMapper.login(user);
    }
}

按照这样的方式进行拼接信息

输入后会查询数据库，把查询结果返回控制台

注意：

主要的思路而不是代码的实现，思路重要！思路！思路！思路！