【Java从0到架构师】SpringBoot - MyBatis

╰+攻爆jí腚メ 2022-09-04 07:44 184阅读 0赞

### SpringBoot - MyBatis ###

*  集成 MyBatis
 *   *  引入依赖
     *  数据源配置 - 源码
     *  MyBatis 配置 - 源码
     *  扫描 Dao
     *  MyBatis 主配置 - XML、注解、application
     *   *  XML配置
         *  注解
         *  application
 *  starter 的命名规范

> Java 从 0 到架构师目录：[【Java从0到架构师】学习记录][Java_0]

Gitee 代码：[https://gitee.com/szluyu99/mj\_java\_frame/tree/master/04\_SpringBoot][https_gitee.com_szluyu99_mj_java_frame_tree_master_04_SpringBoot]

# 集成 MyBatis #

示例代码：[SpringBoot 集成 MyBatis][SpringBoot _ MyBatis]

## 引入依赖 ##

> 参考：[http://mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/][http_mybatis.org_spring-boot-starter_mybatis-spring-boot-autoconfigure]

一般来说，SpringBoot 认为常用的库都会在 parent 项目中锁定了版本，例如 mysql

<dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>2.1.3</version>
    </dependency>
    
    
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
    
    
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
        <version>1.2.1</version>
    </dependency>

## 数据源配置 - 源码 ##

spring:
      datasource:
        type: com.alibaba.druid.pool.DruidDataSource
        driver-class-name: com.mysql.cj.jdbc.Driver
        username: root
        password: root
        url: jdbc:mysql://localhost:3306/test_mybatis?serverTimezone=UTC
        druid:
          initial-size: 5
          max-active: 10

数据源的相关配置，可以参考：

*  spring-boot-autoconfigure.jar 中的 DataSourceProperties 类  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzczNDA5NQ_size_16_color_FFFFFF_t_70]  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzczNDA5NQ_size_16_color_FFFFFF_t_70 1]  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzczNDA5NQ_size_16_color_FFFFFF_t_70 2]
 *  druid-spring-boot-autoconfigure.jar 中的 DruidDataSourceWrapper 类  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzczNDA5NQ_size_16_color_FFFFFF_t_70 3]

## MyBatis 配置 - 源码 ##

mybatis:
    # mapper-locations: classpath:/mappers/*.xml
    # config-location: classpath:mybatis-config.xml
      type-aliases-package: com.mj.domain
      configuration:
        map-underscore-to-camel-case: true
        use-generated-keys: true

MyBatis 相关的配置，可以参考：

*  mybatis-spring-boot-autoconfigure.jar 中的 MybatisProperties 类  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzczNDA5NQ_size_16_color_FFFFFF_t_70 4]

## 扫描 Dao ##

@SpringBootApplication
    @MapperScan("com.mj.dao")
    public class Application { 
        public static void main(String[] args) { 
            SpringApplication.run(Application.class, args);
        }
    }

## MyBatis 主配置 - XML、注解、application ##

> useGeneratedkeys 除了可以在 mapper 中单独配置，也可以进行全局统一配置（3种方式）  
> 下面的配置中包含了 mapUnderscoreToCamelCase 和 useGeneratedkeys

MyBatis 主配置文件主要有以下三种形式：

*  使用额外的 **XML** 文件，然后在 SpringBoot 中引入该 XML（通用）
 *  利用**注解**实现纯代码进行配置（SpringBoot 专用）
 *  在 **application** 中进行配置（SpringBoot 专用）

### XML配置 ###

在 application 中指定 mybatis 配置文件的位置：

mybatis:
      config-location: classpath: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>
        <settings>
            
            <setting name="useGeneratedKeys" value="true"/>
            
            <setting name="mapUnderscoreToCamelCase" value="true"/>
        </settings>
    </configuration>

### 注解 ###

@Configuration
    public class MyBatisConfig { 
        @Bean
        public ConfigurationCustomizer customizer() { 
            return (configuration) -> { 
                configuration.setMapUnderscoreToCamelCase(true);
                configuration.setUseGeneratedKeys(true);
            };
        }
    }

### application ###

mybatis:
      configuration:
        map-underscore-to-camel-case: true
        use-generated-keys: true

# starter 的命名规范 #

SpringBoot 官方提供的 starter：**spring-boot-starter-\***

自定义的 starter（非 SpringBoot 官方）：**\*\-spring-boot-starter**

参考：[官方文档][Link 1]

[Java_0]: https://blog.csdn.net/weixin_43734095/article/details/119067034
[https_gitee.com_szluyu99_mj_java_frame_tree_master_04_SpringBoot]: https://gitee.com/szluyu99/mj_java_frame/tree/master/04_SpringBoot
[SpringBoot _ MyBatis]: https://gitee.com/szluyu99/mj_java_frame/tree/master/04_SpringBoot/00_parent/47_MyBatis
[http_mybatis.org_spring-boot-starter_mybatis-spring-boot-autoconfigure]: http://mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/
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[Link 1]: https://docs.spring.io/spring-boot/docs/current/reference/html/using.html#using-boot-starter