springboot学习笔记（三)

LK接着上面的，来总结一下springboot与数据源的操作，毕竟做web数据库是少不了的，今天就springboot和mysql整合做一总结:
1. springboot+mybaties整合之注解形式
2. springboot+mybaties整合之xml形式
3. springboot+mybatiesplus+driud数据源整合
4. springboot+mybatiesplus+driud多数据源配置

1.springboot+mybaties整合之注解形式

步骤：

• 添加依赖

<dependency>
   		<groupId>org.mybatis.spring.boot</groupId>
   		<artifactId>mybatis-spring-boot-starter</artifactId>
   		<version>2.0.1</version>
   	</dependency>

   	<dependency>
   		<groupId>mysql</groupId>
   		<artifactId>mysql-connector-java</artifactId>
   		<scope>runtime</scope>
   	</dependency>

• 配置数据源信息

mybatis.type-aliases-package = com.yrz.model

spring.datasource.url = jdbc：mysql：// localhost：3306 / test？serverTimezone = UTC＆useUnicode = true＆characterEncoding = utf-8＆useSSL = true
spring.datasource.username = root
spring.datasource.password = 123456
spring.datasource.driver-class-name = com.mysql.cj.jdbc.Driver

• mapper接口实例

public interface UserMapper {
   @Select("SELECT * FROM users")
   @Results({
   	@Result(property = "userSex",  column = "user_sex"),
   	@Result(property = "nickName", column = "nick_name")
   })
   List<User> getAllUser();

   @Select("SELECT * FROM users WHERE id = #{id}")
   @Results({
   	@Result(property = "userSex",  column = "user_sex"),
   	@Result(property = "nickName", column = "nick_name")
   })
   User getOne(Long id);


   @Insert("INSERT INTO users(userName,passWord,user_sex) VALUES(#{userName}, #{passWord}, #{userSex})")
   void insert(User user);

   @Update("UPDATE users SET userName=#{userName},nick_name=#{nickName} WHERE id =#{id}")
   void update(User user);

   @Delete("DELETE FROM users WHERE id =#{id}")
   void delete(Long id);
}

• Controller用于演示，可以用测试类

@RestController
public class UserController {
	
	@Autowired
	private UserMapper userMapper;
	
	@RequestMapping("/getUsers")
	public List<User> getUsers() {
		List<User> users=userMapper.getAllUser();
		return users;
	}
	
    @RequestMapping("/getUser")
    public User getUser(Long id) {
    	User user=userMapper.getOne(id);
        return user;
    }
    
    @RequestMapping("/add")
    public void save(User user) {
    	userMapper.insert(user);
    }
    
    @RequestMapping(value="update")
    public void update(User user) {
    	userMapper.update(user);
    }
    
    @RequestMapping(value="/delete/{id}")
    public void delete(@PathVariable("id") Long id) {
    	userMapper.delete(id);
    }
    
    
}

• 启动类上映射mapper

@SpringBootApplication
@MapperScan("com.yrz.mapper")
public class SpringbootMybatiesApplication {

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

}

• 实例结果
  
  源码 请在 https://github.com/TDYRZ/spring-/tree/master/springboot-mybaties-annotion 上获取

2.springboot+mybaties整合之xml形式

LK对XML的配置比较情有独钟，毕竟一直在使用这种形式，springboot也支持xml形式的配置。来看看具体配置：

• xml配置

<?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.yrz.mapper.UserMapper" >
   <resultMap id="BaseResultMap" type="com.yrz.model.User" >
       <id column="id" property="id" jdbcType="BIGINT" />
       <result column="userName" property="userName" jdbcType="VARCHAR" />
       <result column="passWord" property="passWord" jdbcType="VARCHAR" />
       <result column="user_sex" property="userSex" jdbcType="VARCHAR"/>
       <result column="nick_name" property="nickName" jdbcType="VARCHAR" />
   </resultMap>
   
   <sql id="Base_Column_List" >
       id, userName, passWord, user_sex, nick_name
   </sql>

   <select id="getAllUser" resultMap="BaseResultMap"  >
      SELECT 
      <include refid="Base_Column_List" />
      FROM users
   </select>

   <select id="getOne" parameterType="java.lang.Long" resultMap="BaseResultMap" >
       SELECT 
      <include refid="Base_Column_List" />
      FROM users
      WHERE id = #{id}
   </select>

   <insert id="insert" parameterType="com.yrz.model.User" >
      INSERT INTO 
      		users
      		(userName,passWord,user_sex) 
      	VALUES
      		(#{userName}, #{passWord}, #{userSex})
   </insert>
   
   <update id="update" parameterType="com.yrz.model.User" >
      UPDATE 
      		users 
      SET 
      	<if test="userName != null">userName = #{userName},</if>
      	<if test="passWord != null">passWord = #{passWord},</if>
      	nick_name = #{nickName}
      WHERE 
      		id = #{id}
   </update>
   
   <delete id="delete" parameterType="java.lang.Long" >
      DELETE FROM
      		 users 
      WHERE 
      		 id =#{id}
   </delete>

</mapper>

resource目录下新建一个UserMapper.xml文件夹

• 配置文件中配置xml

mybatis.mapper-locations=classpath:mapper/*.xml
mybatis.type-aliases-package=com.yrz.model

spring.datasource.url=jdbc:mysql://localhost:3306/test?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

• dao层实现

@Mapper
public interface UserMapper {
	
	List<User> getAllUser();

	
	User getOne(Long id);


	void insert(User user);

	void update(User user);

	void delete(Long id);
}

此处使用@Mapper注解，在启动类上就不用在引入dao层包了。
源码请在https://github.com/TDYRZ/spring-/tree/master/springboot-mybites-xml上获取

3.springboot+mybatiesplus+driud数据源整合

首先来介绍一下mybites增强工具mybatiesplus，它是在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。 特性:

• 无侵入：只做增强不做改变，引入它不会对现有工程产生影响，如丝般顺滑
• 损耗小：启动即会自动注入基本 CURD，性能基本无损耗，直接面向对象操作
• 强大的 CRUD 操作：内置通用 Mapper、通用 Service，仅仅通过少量配置即可实现单表大部分 CRUD 操作，更有强大的条件构造器，满足各类使用需求
  其他特性请参考官网—https://mp.baomidou.com，废话不多说来看看具体配置
• 依赖引入(mybatisplus-spring-boot-starte和druid)

			<!-- mybatis-plus begin -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-jdbc</artifactId>
		</dependency>
		<dependency>
			<groupId>com.baomidou</groupId>
			<artifactId>mybatisplus-spring-boot-starter</artifactId>
			<version>${mybatisplus-spring-boot-starter.version}</version>
		</dependency>
		<dependency>
			<groupId>com.baomidou</groupId>
			<artifactId>mybatis-plus</artifactId>
			<version>${mybatisplus.version}</version>
		</dependency>
		<!-- mybatis-plus end -->
<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>druid</artifactId>
			<version>${druid.version}</version>
		</dependency>

		<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>druid-spring-boot-starter</artifactId>
			<version>${druid.version}</version>
		</dependency>

• 配置文件（只有单数据源）

   	 server:
   	  port: 8080 #指定tomcat默认端口号
   	
   	spring:
   	  aop:#aop配置
   	    proxy-target-class: true
   	    auto: true
   	  datasource:
   	    druid:
   	      # 数据库 1
   	        url: jdbc:mysql://localhost:3306/db1?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
   	        username: root
   	        password: 123456
   	        driver-class-name: com.mysql.jdbc.Driver
   	        initialSize: 5
   	        minIdle: 5
   	        maxActive: 20

• MybatisPlusConfig类用来配置数据源，分页插件，mybaties配置。这里只配置了分页插件

/**
* @Author yrz
*/
@Configuration
@MapperScan({"com.yrz.mapper*"})
public class MybatisPlusConfig {

   /**
    * mybatis-plus分页插件<br>
    * 文档：http://mp.baomidou.com<br>
    */
   @Bean
   public PaginationInterceptor paginationInterceptor() {
       PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
       //paginationInterceptor.setLocalPage(true);// 开启 PageHelper 的支持
       return paginationInterceptor;
   }

    
 

}

• 配置mapper接口(主要是继承BaseMapper接口)
  mybaties-plus提供了通用的mapper接口
  

/**
* <p>
*  Mapper 接口
* </p>
*
* @author yrz
*/
public interface UserMapper extends BaseMapper<User> {

}

• 配置service接口（主要是继承IService接口）
  

/**
- <p>
-  服务类
- </p>
-  - @author yrz
*/
public interface UserService extends IService<User> {
   List<User> getUserList();
}

• 具体实现类和控制类（主要用于测试）
  项目源码 https://github.com/TDYRZ/spring-/tree/master/springboot-mybitesplus-druid

4. springboot+mybatiesplus+driud多数据源配置

具体实现思路

• 使用db1,db2两个数据源。
• 使用AOP在service层进行数据源判断切换。
• 在mybatiesplusConfig类中注入数据源，对其进行全局配置。

具体代码实现

• 配置文件(mysql下两个数据源 db1 db2)

server:
 port: 8080

spring:
 aop:
   proxy-target-class: true
   auto: true
 datasource:
   druid:
     # 数据库 1
     db1:
       url: jdbc:mysql://localhost:3306/db1?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
       username: root
       password: 123456
       driver-class-name: com.mysql.jdbc.Driver
       initialSize: 5
       minIdle: 5
       maxActive: 20
     # 数据库 2
     db2:
       url: jdbc:mysql://localhost:3306/db2?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
       username: root
       password: 123456
       driver-class-name: com.mysql.jdbc.Driver
       initialSize: 5
       minIdle: 5
       maxActive: 20

• 重点来看看切面类
  切点是放在service层，当调用service的方法时切换数据源。
  判断方法上是否有数据库切换注解，有的话直接使用注解。

@Component
@Aspect
public class DataSourceSwitchAspect {

   @Pointcut("execution(* com.yrz.service.db1.*.*(..))")
   private void db1Aspect() {
   }

   @Pointcut("execution(* com.yrz.service.db2.*.*(..))")
   private void db2Aspect() {
   }
   
   /**
    * 执行service方法之前先切换数据源到db1
   * @Title: db1 
   * @Description: TODO(这里用一句话描述这个方法的作用) 
   * @param @param joinPoint 设定文件 
   * @author:yrz
   * @data: 2019年5月21日 下午4:48:06 
   * @return void 返回类型 
   * @throws
    */
   @Before( "db1Aspect()" )
   public void db1(JoinPoint joinPoint) {
      System.out.println("切换到db1 数据源...");
       setDataSource(joinPoint,DBTypeEnum.db1);
   }
   
   /**
    * 执行service方法之前先切换数据源到db2
   * @Title: db1 
   * @Description: TODO(这里用一句话描述这个方法的作用) 
   * @param @param joinPoint 设定文件 
   * @author:yrz
   * @data: 2019年5月21日 下午4:48:06 
   * @return void 返回类型 
   * @throws
    */
   @Before("db2Aspect()" )
   public void db2 (JoinPoint joinPoint) {
       System.out.println("切换到db2 数据源...");
       setDataSource(joinPoint,DBTypeEnum.db2);
   }
   /**
    * 添加注解方式,如果有注解优先注解,没有则按传过来的数据源配置
    * @param joinPoint
    * @param dbTypeEnum
    */
   private void setDataSource(JoinPoint joinPoint, DBTypeEnum dbTypeEnum) {
       MethodSignature methodSignature = (MethodSignature) joinPoint.getSignature();
       DataSourceSwitch dataSourceSwitch = methodSignature.getMethod().getAnnotation(DataSourceSwitch.class);
       if (Objects.isNull(dataSourceSwitch) || Objects.isNull(dataSourceSwitch.value())) {
           DbContextHolder.setDbType(dbTypeEnum);
       }else{
           System.out.println("根据注解来切换数据源,注解值为:"+dataSourceSwitch.value());
           switch (dataSourceSwitch.value().getValue()) {
               case "db1":
                   DbContextHolder.setDbType(DBTypeEnum.db1);
                   break;
               case "db2":
                   DbContextHolder.setDbType(DBTypeEnum.db2);
                   break;
               default:
                   DbContextHolder.setDbType(dbTypeEnum);
           }
       }
   }
}

• 不同数据源注入容器

**
* @Author yrz
*/
@Configuration
@MapperScan({"com.yrz.mapper*"})
public class MybatisPlusConfig {

   /**
    * mybatis-plus分页插件<br>
    * 文档：http://mp.baomidou.com<br>
    */
   @Bean
   public PaginationInterceptor paginationInterceptor() {
       PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
       //paginationInterceptor.setLocalPage(true);// 开启 PageHelper 的支持
       return paginationInterceptor;
   }

   //注入“db1”数据源
   @Bean(name = "db1")
   @ConfigurationProperties(prefix = "spring.datasource.druid.db1" )
   public DataSource db1 () {
       return DruidDataSourceBuilder.create().build();
   }
 
   //注入“db2”数据源
   @Bean(name = "db2")
   @ConfigurationProperties(prefix = "spring.datasource.druid.db2" )
   public DataSource db2 () {
       return DruidDataSourceBuilder.create().build();
   }
   /**
    * 动态数据源配置
    * @return
    */
   @Bean
   @Primary
   public DataSource multipleDataSource (@Qualifier("db1") DataSource db1,
                                         @Qualifier("db2") DataSource db2 ) {
       DynamicDataSource dynamicDataSource = new DynamicDataSource();
       Map< Object, Object > targetDataSources = new HashMap<>();
       targetDataSources.put(DBTypeEnum.db1.getValue(), db1 );
       targetDataSources.put(DBTypeEnum.db2.getValue(), db2);
       dynamicDataSource.setTargetDataSources(targetDataSources);
       dynamicDataSource.setDefaultTargetDataSource(db1);//默认数据源
       return dynamicDataSource;
   }

   //配置mybaties
   @Bean("sqlSessionFactory")
   public SqlSessionFactory sqlSessionFactory() throws Exception {
       MybatisSqlSessionFactoryBean sqlSessionFactory = new MybatisSqlSessionFactoryBean();
       sqlSessionFactory.setDataSource(multipleDataSource(db1(),db2()));

       MybatisConfiguration configuration = new MybatisConfiguration();
       configuration.setJdbcTypeForNull(JdbcType.NULL);
       configuration.setMapUnderscoreToCamelCase(true);
       configuration.setCacheEnabled(false);
       sqlSessionFactory.setConfiguration(configuration);
       sqlSessionFactory.setPlugins(new Interceptor[]{ //PerformanceInterceptor(),OptimisticLockerInterceptor()
               paginationInterceptor()
       });
       sqlSessionFactory.setGlobalConfig(globalConfiguration());
       return sqlSessionFactory.getObject();
   }

   //全局配置
   @Bean
   public GlobalConfiguration globalConfiguration() {
       GlobalConfiguration conf = new GlobalConfiguration(new LogicSqlInjector());
       conf.setLogicDeleteValue("-1");
       conf.setLogicNotDeleteValue("1");
       conf.setIdType(0);
      // conf.setMetaObjectHandler(new MyMetaObjectHandler());
       conf.setDbColumnUnderline(true);
       conf.setRefresh(true);
       return conf;
   }
   

}

测试结果：
项目源码 https://github.com/TDYRZ/spring-/tree/master/springboot-mybitesplus-druidMultipledatasources

至此 springboot整合mybaties历经简单到多数据源配置，因为LK一直使用mybaties所以以此作为实例，如果有兴趣可以使用jpa实现。