# ssm整合：mybatis層
###### tags: `ssm整合`

## SQL
### 1.先創建資料庫

CREATE DATABASE `ssmbuild`;

USE `ssmbuild`;

DROP TABLE IF EXISTS `books`;

CREATE TABLE `books` (
`bookID` INT(10) NOT NULL AUTO_INCREMENT COMMENT '书id',
`bookName` VARCHAR(100) NOT NULL COMMENT '书名',
`bookCounts` INT(11) NOT NULL COMMENT '数量',
`detail` VARCHAR(200) NOT NULL COMMENT '描述',
KEY `bookID` (`bookID`)
) ENGINE=INNODB DEFAULT CHARSET=utf8

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');


## 搭建環境
### 1.新建一Maven项目！ssmbuild ， 添加web的支持
### 2.导入相关的pom依赖

<!--依賴：junit、數據庫驅動、連接池、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>5.1.47</version>
        </dependency>
        <!-- 数据库连接池 -->
        <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>2.2</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>2.0.2</version>
        </dependency>

        <!--Spring-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.1.9.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.1.9.RELEASE</version>
        </dependency>
    </dependencies>

### 3.Maven资源过滤设置

<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>

### 4.連接數據庫
連接數據庫的位置
輸入數據庫的帳密
選擇要連接的數據庫
成功連結後的狀態

## 建立基本結構
1.基本的資料夾

2.mybatis配置環境用文件

<?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>

3.spring的環境配置文件

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

</beans>

4.mybatis-config.xml要與數據庫連接，要先寫database.properties來關聯數據庫
database.properties的內容，有關要連接數據庫的資料(例如帳密等等)

jdbc.driver=com.mysql.jdbc.Driver
# 如果使用的是MySQL8.0+，增加一個時區的配置
jdbc.url=jdbc:mysql://localhost:3306/ssmbuild?serverTimezone=Asia/Shanghai&useSSL=true&useUnicode=true&characterEncoding=utf8
jdbc.username=root
jdbc.password=123456

5.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>
<!--配置數據源，交給Spring去做-->
    <typeAliases>
        <package name="com.kuang.pojo"/>
    </typeAliases>

    
</configuration>

## pojo層
1.建立實體類

public class Books {
    private int bookID;
    private String bookName;
    private int bookCounts;
    private String details;
}

2.導入Lombok，讓實體類可以使用帶有造構造器的註解

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.24</version>
        </dependency>

3.使用註解

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Books {
    private int bookID;
    private String bookName;
    private int bookCounts;
    private String details;
}

上面註解的效果

## dao層
1.寫接口

public interface BookMapper {

    //增加一本書
    int addBook(Books books);
    //刪除一本書
    int deleteBookByID(@Param("bookId") int id);
    //更新一本書
    int updateBook(Books books);
    //查詢一本書
    Books queryBookById(@Param("bookId")int id);
    //查詢全部的書
    List<Books> queryAllBook();
}

2.BookMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.kuang.dao.BookMapper">

    <insert id="addBook" parameterType="Books">
        insert into ssmbuild.books (bookName,bookCounts,detail)
        values (#{bookName},#{bookCounts},#{detail})
    </insert>

    <delete id="deleteBookByID" parameterType="int">
        delete from ssmbuild.books
        where bookID = #{bookId}
    </delete>

    <update id="updateBook" parameterType="Books">
        update ssmbuild.books
        set bookName = #{bookName},bookCounts = #{bookCounts},detail = #{detail}
        where bookID = #{bookID}
    </update>

    <select id="queryBookById" resultType="Books">
        select * from ssmbuild.books
        where bookID = # {bookId}
    </select>

    <select id="queryBookById" resultType="Books">
        select * from ssmbuild.books
    </select>

</mapper>

3.BookMapper.xml綁定到mybatis-config.xml配置文件中

    <mappers>
        <mapper class="com.kuang.dao.BookMapper"/>
    </mappers>

## Service層
1.創建BookService接口

public interface BookService {
    //增加一本書
    int addBook(Books books);
    //刪除一本書
    int deleteBookByID(int id);
    //更新一本書
    int updateBook(Books books);
    //查詢一本書
    Books queryBookById(int id);
    //查詢全部的書
    List<Books> queryAllBook();
}

2.BookService的實現類

public class BookServiceImpl implements BookService{

    //service調dao層：組合dao層
    private BookMapper bookMapper;

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

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

    @Override
    public int deleteBookByID(int id) {
        return bookMapper.deleteBookByID(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> queryAllBook() {
        return bookMapper.queryAllBook();
    }
}