SpringBoot 整合Mybatis

女爷i 2022-04-25 08:02 42阅读 0赞

### 一、SpringBoot 整合Mybatis ###

**1、在创建SpringBoot 的项目时，选择JDBC、mysql，Mybatis，web的组件，或者自己手动在maven中添加库依赖：**

<dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
    
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-jdbc</artifactId>
            </dependency>
    
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <scope>runtime</scope>
            </dependency>
       
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>1.3.2</version>
            </dependency>

**2、在 application.yml（或aproperties）中添加相应的配置：**

**    ** 注意 ：配置 mybatis 的配置文件位置

server:
      port: 80
    
    # Datasource
    # 数据源基本配置
    spring:
      datasource:
        username: root
        password: 123456
        url: jdbc:mysql://localhost:3306/my_springboot?useUnicode=true&characterEncoding=utf8&useSSL=true&serverTimezone=GMT
        driver-class-name: com.mysql.cj.jdbc.Driver # com.mysql.jdbc.Driver
    
    # 配置mybatis的配置文件的位置
    mybatis:
      config-location: classpath:mybatis/mybatis-config.xml
      mapper-locations: classpath:mybatis/mapper/*.xml
    
    # 打印sql：日志的方式
    logging:
        level:
          # 路径指的是mybatis对应的方法接口所在的包。并不是mapper.xml所在的包
          cn.jq.springbootdemo.springbootdemo.dao : debug

**3、新建一个model, dao类:**

在测试类中测试，所以 service 和controller就不写了

public class User {
    
        private long id;
        private String username;
        private String pazzword;
        private String sex;
        private int age;
        private Date birthday;
        ...
    }

public interface UserDao {
        void add(User user);
        void delete(int id);
        void update(User user);
        User get(int id);
    }

**4、在 resources 下创建一个mybatis文件夹，在其下新建 mybatis-config.xml 全局配置mybatis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>
        <settings>
            <setting name="mapUnderscoreToCamelCase" value="true"/>
        </settings>
    </configuration>

**5、在 mybatis 下新建 mapper 文件夹，在其下新建 \*.xml 映射文件**

<?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="cn.jq.springbootdemo.springbootdemo.dao.UserDao">
    
        <insert id="add">
            insert into t_user(username, pazzword, sex, age, birthday)
            values(#{username},#{pazzword},#{sex},#{age},#{birthday})
        </insert>
        <delete id="delete">
          delete from t_user where id = #{id}
        </delete>
        <update id="update">
            update t_user u set u.username = #{username}, u.sex = #{sex} where id = #{id}
        </update>
        <select id="get" resultType="cn.jq.springbootdemo.springbootdemo.model.User">
            select id, username, pazzword, sex, age, birthday from t_user where id = #{id}
        </select>
    </mapper>

**6、 在 启动类中 添加** **@MapperScan** **注解 扫描 mapper**

配置mapper扫描，有两种方式：

*  1. 是直接在UserDao类上添加@Mapper注解，弊端是所有的Mapper都要手动添加，要是有一个没添加就会报错。
 *  2. 直接在启动类上添加Mapper扫描，推荐使用。

@SpringBootApplication
    @MapperScan(value = "cn.jq.springbootdemo.springbootdemo.dao")
    public class SpringbootdemoApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(SpringbootdemoApplication.class, args);
        }
    
    }

**7、 在 测试类中 进行 CRUD**

@RunWith(SpringRunner.class)
    @SpringBootTest
    public class SpringbootdemoApplicationTests {
        @Autowired
        private UserDao userDao;
    
        @Test
        public void contextLoads() throws SQLException {        
            System.out.println(userDao);
    
            // 新增
    //        User user = new User();
    //        user.setUsername("张三");
    //        user.setPazzword("zhs123");
    //        user.setSex("男");
    //        user.setAge(20);
    //        user.setBirthday(new Date());
    //        userDao.add(user);
    
            // 删除
            //userDao.delete(1);
    
            // 修改
            User user = new User();
            user.setId(6);
            user.setUsername("张三6");
            user.setSex("女");
            userDao.update(user);
            
            // 查询
            user = userDao.get(6);
            System.out.println("getUser==" + user);
        }
    }

![20190530162508389.png][]

数据表：

CREATE TABLE `t_user` (
      `id` int(11) NOT NULL AUTO_INCREMENT,
      `username` varchar(255) DEFAULT NULL,
      `pazzword` varchar(255) DEFAULT NULL,
      `age` int(11) DEFAULT NULL,
      `birthday` datetime DEFAULT NULL,
      `sex` varchar(11) DEFAULT NULL,
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8;

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQyNDAyODU0_size_16_color_FFFFFF_t_70][]

### 二、SpringBoot 整合Mybatis ###

上面xml和mapper分离了，查看阅读不直观。这里方式二整合如下：不同点这里列出来。

**1、在 application.yaml**

这里不需要配置mybatis的配置文件的位置，放到pom中配置。

server:
      port: 8088
    
    # 数据源基本配置
    spring:
      datasource:
        username: root
        password: 123456
        url: jdbc:mysql://localhost:3306/sbtdb1?useUnicode=true&characterEncoding=utf8&useSSL=true&serverTimezone=GMT
        driver-class-name: com.mysql.cj.jdbc.Driver
        type: com.alibaba.druid.pool.DruidDataSource

**2、引入依赖之后，在插件中加入：**

<build>
            
            <resources>
                <resource>
                    <directory>src/main/java</directory>
                    <includes>
                        <include>**/*.xml</include>
                    </includes>
                </resource>
                <resource>
                    <directory>src/main/resources</directory>
                </resource>
            </resources>
    ...
        </build>

3、UserMapper和xml

public interface UserMapper {
    
        List<User> listAll();
    }

<?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.example.mybatis.mapper.UserMapper">
    
        <select id="listAll" resultType="com.example.mybatis.pojo.User">
            select id,name,password from t_user
        </select>
    </mapper>

4、测试

@SpringBootApplication
    @MapperScan(basePackages ={"com.example.mybatis.mapper"})
    public class MybatisApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(MybatisApplication.class, args);
        }
    
    }

@RestController
    public class UserController {
    
        @Autowired
        private UserMapper userMapper;
    
        @GetMapping("/list")
        public List<User> list(){
            List<User> list = userMapper.listAll();
            return list;
        }
    
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQyNDAyODU0_size_16_color_FFFFFF_t_70 1][]

### 三、SpringBoot 配置多数据源之Mybatis ###

**1、在创建SpringBoot 的项目时，引入依赖，在插件中声明 .xml**

<dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
    
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>2.1.1</version>
            </dependency>
    
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <scope>runtime</scope>
            </dependency>
    
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid-spring-boot-starter</artifactId>
                <version>1.1.13</version>
            </dependency>
    
    
        <build>
            
            <resources>
                <resource>
                    <directory>src/main/java</directory>
                    <includes>
                        <include>**/*.xml</include>
                    </includes>
                </resource>
                <resource>
                    <directory>src/main/resources</directory>
                </resource>
            </resources>
    ...
        </build>

**2、在 application.aproperties中添加两个数据源的配置信息**

server.port=8088
    # 配置两个数据源
    spring.datasource.dsone.url=jdbc:mysql://localhost:3306/sbtdb1?useUnicode=true&characterEncoding=utf8&useSSL=true&serverTimezone=GMT
    spring.datasource.dsone.username=root
    spring.datasource.dsone.password=123456
    spring.datasource.dsone.type=com.alibaba.druid.pool.DruidDataSource
    spring.datasource.dsone.driver-class-name=com.mysql.cj.jdbc.Driver
    
    spring.datasource.dstwo.url=jdbc:mysql://localhost:3306/sbtdb2?useUnicode=true&characterEncoding=utf8&useSSL=true&serverTimezone=GMT
    spring.datasource.dstwo.username=root
    spring.datasource.dstwo.password=123456
    spring.datasource.dstwo.type=com.alibaba.druid.pool.DruidDataSource
    spring.datasource.dstwo.driver-class-name=com.mysql.cj.jdbc.Driver

**3、在配置类中，定义两个DataSource Bean**

@Configuration
    public class DataSourceConfig {
        /**
         * 定义两个DataSource
         * 使用spring.datasource.dsone前缀的数据库配置去创建一个DataSource
         */
        @Bean("dsOne")
        @ConfigurationProperties(prefix = "spring.datasource.dsone")
        DataSource dsOne() {
            return DruidDataSourceBuilder.create().build();
        }
    
        @Bean("dsTwo")
        @ConfigurationProperties(prefix = "spring.datasource.dstwo")
        DataSource dsTwo() {
            return DruidDataSourceBuilder.create().build();
        }
    
    }

**4、提供两个Bean，并配置数据源**

@Configuration
    @MapperScan(basePackages = "com.example.mybatis.mapper1",
            sqlSessionFactoryRef = "sqlSessionFactory1",
            sqlSessionTemplateRef = "sqlSessionTemplate1")
    public class MyBatisConfigOne {
        @Resource(name = "dsOne")
        DataSource dsOne;
    
        @Bean
        SqlSessionFactory sqlSessionFactory1() {
            SqlSessionFactory sessionFactory = null;
            try {
                SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
                bean.setDataSource(dsOne);
                sessionFactory = bean.getObject();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return sessionFactory;
        }
    
        @Bean
        SqlSessionTemplate sqlSessionTemplate1() {
            return new SqlSessionTemplate(sqlSessionFactory1());
        }
    }

@Configuration
    @MapperScan(basePackages = "com.example.mybatis.mapper2",
            sqlSessionFactoryRef = "sqlSessionFactory2",
            sqlSessionTemplateRef = "sqlSessionTemplate2")
    public class MyBatisConfigTwo {
        @Resource(name = "dsTwo")
        DataSource dsTwo;
    
        @Bean
        SqlSessionFactory sqlSessionFactory2() {
            SqlSessionFactory sessionFactory = null;
            try {
                SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
                bean.setDataSource(dsTwo);
                sessionFactory = bean.getObject();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return sessionFactory;
        }
    
        @Bean
        SqlSessionTemplate sqlSessionTemplate2() {
            return new SqlSessionTemplate(sqlSessionFactory2());
        }
    }

**5、mapper创建(mapper1和mapper2根据业务去写)**

public interface UserMapper1 {
    
        List<User> listAll();
    }

<?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.example.mybatis.mapper1.UserMapper1">
    
        <select id="listAll" resultType="com.example.mybatis.pojo.User">
            select id,name,password from t_user
        </select>
    </mapper>

**6、测试**

@SpringBootApplication
    public class MybatisApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(MybatisApplication.class, args);
        }
    
    }

@RestController
    public class UserController {
    
        @Autowired
        private UserMapper1 userMapper1;
    
        @Autowired
        private UserMapper2 userMapper2;
    
        @GetMapping("/list1")
        public List<User> list(){
            List<User> list = userMapper1.listAll();
            return list;
        }
    
        @GetMapping("/list2")
        public List<User> list2(){
            List<User> list = userMapper2.listAll();
            return list;
        }
    
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQyNDAyODU0_size_16_color_FFFFFF_t_70 2][]   ![20201104152747257.png][]

在Spring Boot中，查看org.mybatis.spring.boot.autoconfigure.MybatisAutoConfiguration类中，可以看到Spring Boot提供了两个Bean（一个SqlSessionFactory，一个sqlSessionTemplate）。

单数据源时，我们指明数据源配置信息，SpringBoot可自动为我们创建好这两个bean。

多数据源时，我们根据数据源配置信息，可以自已定义创建这两个bean。

有兴趣可以查看下源码。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQyNDAyODU0_size_16_color_FFFFFF_t_70 3][]

参考文章：[http://www.javaboy.org/2019/0407/mybatis-multi.html][http_www.javaboy.org_2019_0407_mybatis-multi.html]

ends ~

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[20201104152747257.png]: /images/20220125/6a4f38b24b3c44c0b979cfd2c9455d7f.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQyNDAyODU0_size_16_color_FFFFFF_t_70 3]: /images/20220125/49580ec286504cca9c83ce0a63e8aa94.png
[http_www.javaboy.org_2019_0407_mybatis-multi.html]: http://www.javaboy.org/2019/0407/mybatis-multi.html