1. 先配置数据库

CREATE DATABASE `ssmbuild`;
USE `ssmbuild`; 


CREATE TABLE `books` (
`bookID` INT(10) NOT NULL primary key,
`bookName` VARCHAR(100) NOT NULL,
`bookCounts` INT(11) NOT NULL ,
`detail` VARCHAR(200) NOT NULL 
);

INSERT  INTO `books`(`bookID`,`bookName`,`bookCounts`,`detail`)VALUES
(1,'Java',1,'从入门到放弃'),
(2,'MySQL',10,'从删库到跑路'),
(3,'Linux',5,'从进门到进牢');

2.java基本jar包导入

1、新建一Maven项目！

2、导入相关的pom依赖！

<!--依赖： junit 数据库驱动 连接池 servlet jsp mybatis mybatis-spring spring-->
    <dependencies>
        <!--Junit-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <!--数据库驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.27</version>
        </dependency>
        <!-- 数据库连接池 c3p0 -->
        <dependency>
            <groupId>com.mchange</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.5.2</version>
        </dependency>

        <!--Servlet - JSP -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.1</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <!--Mybatis-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.2</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.6</version>
        </dependency>

        <!--Spring-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.2.1.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>RELEASE</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>
    <!--静态资源导出问题-->
    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
        </resources>
    </build>

3.建立基本的骨架

        （1）pojo         实体类层

        （2）dao          数据层

        （3）service    业务层

        （4）controller 控制层

三大配置

1.mybatis-config的配置

        -- typeAliases 起别名 在设置返回参数类型可以用当前类的类名

        --mapper 映射我们实现dao接口的xml文件

<?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>
 
</configuration>

2.spring的配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd">

</beans>

3.web.xml的配置

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee       
         http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
   
</web-app>

=================================================

mybatis层

1.数据库配置文件database.properties

driver=com.mysql.cj.jdbc.Driver
url =jdbc:mysql://localhost:3306/ssmbuild?useSSL=true&useUnicode=true&characterEncoding=utf8
username=koko
password=mxkmxk12567

#数据库配置文件

2.IDEA关联数据库  mysql

3.编写mybatis的核心配置文件

<?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>
    <!--别名，dao层方法的返回值可以为实体类的类名了-->
    <typeAliases>
        <package name="com.ma.pojo"/>
    </typeAliases>
    <!--mappers 映射dao接口的实现xml-->
    <mappers>
        <mapper resource="com/ma/dao/BookMapper.xml"/>
    </mappers>
</configuration>

4.编写与数据库字段一一对应的实体类

懒人使用lombok插件！ （快速实现属性、方法的编写）

package com.ma.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.web.bind.annotation.PathVariable;

// 使用@Data注解可以快速实现类的属性和方法 （但没有有参函数）
@Data
// 使用@AllArgsConstructor 可以实现有参函数 （但无参函数被干掉了）
@AllArgsConstructor
// 使用@NoArgsConstructor 显示写入无参函数
@NoArgsConstructor
public class Books {
    private int bookID;
    private String bookName;
    private int bookCounts;
    private String detail;
}

5、编写Dao层的 Mapper接口！

package com.ma.dao;

import com.ma.pojo.Books;

import java.util.List;

public interface BookMapper {
    // 增加一本书
    int addBook(Books books);
    // 删除一本书
    int deleteBook(int id);
    // 更新一本书
    int updateBook(Books books);
    // 查询一本书
    Books queryBookById(int id);
    // 查询所有书
    List<Books> queryBooks();
}

6、编写接口对应的 Mapper.xml 文件。需要导入MyBatis的包；

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.ma.dao.BookMapper">
    <!--插入一条数据-->
    <insert id="addBook" parameterType="Books">
        insert into ssmbuild.books (bookID, bookName, bookCounts, detail) values(#{bookID},#{bookName},#{bookCounts},#{detail});
    </insert>
    <delete id="deleteBook" parameterType="int">
        delete from ssmbuild.books where bookID = #{bookID}
    </delete>
    <update id="updateBook" parameterType="Books">
        update ssmbuild.books set bookCounts = #{bookCounts} where bookID = #{bookID}
    </update>
    <select id="queryBookById" resultType="Books" parameterType="int">
        select * from ssmbuild.books where bookID=#{bookID}
    </select>
    <select id="queryBooks" resultType="Books">
        select * from ssmbuild.books
    </select>
</mapper>

7、编写Service层的接口和实现类    （service主要调用dao层，所以service接口和dao层一样，主要通过在service 实现类中，通过set注入dao层，调用dao层的方法）

接口：

package com.ma.service;

import com.ma.pojo.Books;

import java.util.List;

public interface BookService {
    // 增加一本书
    int addBook(Books books);
    // 删除一本书
    int deleteBook(int id);
    // 更新一本书
    int updateBook(Books books);
    // 查询一本书
    Books queryBookById(int id);
    // 查询所有书
    List<Books> queryBooks();
}

实现类：

package com.ma.service;

import com.ma.dao.BookMapper;
import com.ma.pojo.Books;

import java.util.List;

public class BookServiceImpl implements BookService{
    // 通过service去调用dao层
    private BookMapper bookMapper;
    // set注入


    public void setBookMapper(BookMapper bookMapper) {
        this.bookMapper = bookMapper;
    }

    @Override
    public int addBook(Books books) {
        return bookMapper.addBook(books);
    }

    @Override
    public int deleteBook(int id) {
        return bookMapper.deleteBook(id);
    }

    @Override
    public int updateBook(Books books) {
        return bookMapper.updateBook(books);
    }

    @Override
    public Books queryBookById(int id) {
        return bookMapper.queryBookById(id);
    }

    @Override
    public List<Books> queryBooks() {
        return bookMapper.queryBooks();
    }
}

=================================================

spring-dao层

我们通过spring去接管我们的mybatis层

我们在spring-dao层中做连接池，做sqlSessionFactory的工厂，把Dao接口注入到spring容器中

<?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">

    <!--关联数据库配置文件-->
    <context:property-placeholder location="classpath:database.properties"/>

    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="${driver}"/>
        <property name="jdbcUrl" value="${url}"/>
        <property name="user" value="${username}"/>
        <property name="password" value="${password}"/>


        <!-- c3p0连接池的私有属性 -->
        <property name="maxPoolSize" value="30"/>
        <property name="minPoolSize" value="10"/>
        <!-- 关闭连接后不自动commit -->
        <property name="autoCommitOnClose" value="false"/>
        <!-- 获取连接超时时间 -->
        <property name="checkoutTimeout" value="10000"/>
        <!-- 当获取连接失败重试次数 -->
        <property name="acquireRetryAttempts" value="2"/>
    </bean>
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!--注入数据库连接池-->
        <property name="dataSource" ref="dataSource"/>
        <!--配置mybatis的全局配置文件-->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
    </bean>

    <!-- 4.配置扫描Dao接口包，动态实现Dao接口注入到spring容器中 -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!--注入sqlSessionFactory-->
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
        <!-- 给出需要扫描Dao接口包 -->
        <property name="basePackage" value="com.ma.dao"/>
    </bean>
</beans>

Spring-service层

<?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">

    <!--1.扫描service下的包-->
    <context:component-scan base-package="com.ma.service"/>

    <!--2.将我们的所有业务类注入到spring，可通过配置，或者注解实现-->
    <bean id="BookServiceImpl" class="com.ma.service.BookServiceImpl">
        <property name="bookMapper" ref="bookMapper"/>
    </bean>

    <!--3.声明式事务提交-->
    <bean id="TransactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <!--配置数据源-->
        <property name="dataSource" ref="dataSource"/>
    </bean>
</beans>

SpringMVC层

----DispatcherServlet总体接管

        web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee         
         http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <servlet>
        <servlet-name>DispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
 <!--一定要注意:我们这里加载的是总的配置文件，之前被这里坑了！-->  
            <param-value>classpath:applicationContext.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>DispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <!--encodingFilter-->
    <filter>
        <filter-name>encodingFilter</filter-name>
        <filter-class>
            org.springframework.web.filter.CharacterEncodingFilter
        </filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>utf-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>encodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <!--Session过期时间-->
    <session-config>
        <session-timeout>15</session-timeout>
    </session-config>
</web-app>

 spring-web.xml

<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"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       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 
       http://www.springframework.org/schema/mvc 
       https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--映射器 适配器-->
    <mvc:annotation-driven/>
    <!--静态资源过滤 例如css js-->
    <mvc:default-servlet-handler/>


    <!--视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!-- 4.扫描web相关的bean -->
    <context:component-scan base-package="com.ma.controller" />
</beans>

最后Controller层编写类

package com.ma.controller;

import com.ma.pojo.Books;
import com.ma.service.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import java.util.List;

@Controller
@RequestMapping("/books")
public class BookController {
    // controller调service层
    // 怎么调? 通过注解注入
    @Autowired
    @Qualifier("BookServiceImpl")
    private BookService bookService;

    // 查询全部书籍，并且返回一个书籍展示页面
    @RequestMapping("/allbook")
    private String list(Model model){
        List<Books> books = bookService.queryBooks();
        model.addAttribute("list",books);
        return "allbook";
    }
}

总结一下

1.spring-dao层主要操作数据库。    -怎么操作数据库？  ---- 通过mybatis

2.spring-service层调用dao层。       -怎么调用dao层？   ---- dao接口注入到spring service通过spring配置dao接口

3.spring-mvc 主要操作service层。

service怎么调用dao层：

spring-dao层最后的扫描dao层接口注入到spring容器中，是因为service层必须要调dao层，怎么调用dao层？就是通过set注入调用。在spring-service 把实现类注入到容器中，

 通过配置，因为我们已经把dao层注入到spring容器当中了，我们可以通过ref引用获取dao层的接口赋值给service层set注入的dao，从而实现了service调用dao层

controller层怎么控制service层？

通过注解注入service与其原理和调用dao层一致