SpringBoot 采用自定义注解方式管理多数据源和事务

使用aop方式来实现功能

1. 获取依赖的jar包，maven配置文件。使用MyBatis 管理数据库

   <parent>
   		<groupId> org.springframework.boot </groupId>
   		<artifactId>spring-boot-starter-parent </artifactId>
   		<version> 2.0.5.RELEASE </version>
   	</parent>
   
   <dependencies>
   	<dependency>
   		<groupId> org.springframework.boot </groupId>
   		<artifactId> spring-boot-starter </artifactId>
   	</dependency>
   
   	<dependency>
   		<groupId> org.springframework.boot </groupId>
   		<artifactId> spring-boot-starter-web </artifactId>
   	</dependency>
   
   	<dependency>
   		<groupId> org.springframework.boot </groupId>
   		<artifactId> spring-boot-starter-test </artifactId>
   	</dependency>
   
   	<dependency>
   		<groupId>org.springframework.boot</groupId>
   		<artifactId>spring-boot-starter-log4j</artifactId>
   		<version>1.3.8.RELEASE</version>
   	</dependency>
   
   	<dependency>
   		<groupId>org.projectlombok</groupId>
   		<artifactId>lombok</artifactId>
   	</dependency>
   	
   	<dependency>
   		<groupId>mysql</groupId>
   		<artifactId>mysql-connector-java</artifactId>
   	</dependency>
   	
   	<dependency>
   		<groupId>org.mybatis.spring.boot</groupId>
   		<artifactId>mybatis-spring-boot-starter</artifactId>
   		<version>1.3.1</version>
   	</dependency>
   	
   	<dependency>
   		<groupId> org.springframework.boot </groupId>
   		<artifactId> spring-boot-starter-aop </artifactId>
   	</dependency>
   
   </dependencies>
   

2. 装配数据源，两个以上

   ###datasource01
   spring.datasource.test1.jdbc-url=jdbc:mysql:///test1
   spring.datasource.test1.username=root
   spring.datasource.test1.password=root
   spring.datasource.test1.driver-class-name=com.mysql.jdbc.Driver
   
   ###datasource02
   spring.datasource.test2.jdbc-url=jdbc:mysql:///test2
   spring.datasource.test2.username=root
   spring.datasource.test2.password=root
   spring.datasource.test2.driver-class-name=com.mysql.jdbc.Driver
   

3. 多数据源配置类

   @Configuration
   public class DataSourceConfig {
   //数据源1
   @Bean(name="datasource1")
   @ConfigurationProperties(prefix="spring.datasource.test1")
   public DataSource dataSource1(){
   	return DataSourceBuilder.create().build();
   }
   //数据源2
   @Bean(name="datasource2")
   @ConfigurationProperties(prefix="spring.datasource.test2")
   public DataSource dataSource2(){
   	return DataSourceBuilder.create().build();
   }
   
   //配置动态数据源，通过aop切换数据源
   @Primary
   @Bean(name="dynamicDataSource")
   public DataSource dynamicDataSource(){
   	DynamicDataSource dynamicDataSource = new DynamicDataSource();
   	
   	dynamicDataSource.setDefaultTargetDataSource(dataSource1());
   	
   	Map<Object, Object> dbMap = new HashMap<Object, Object>();
   	
   	dbMap.put("datasource1", dataSource1());
   	dbMap.put("datasource2", dataSource2());
   	
   	dynamicDataSource.setTargetDataSources(dbMap);
   	return dynamicDataSource;
   }
   
   //配置Transaction，统一管理
   @Bean(name="transactionManager")
   public PlatformTransactionManager transactionManager(){
   	return new DataSourceTransactionManager(dynamicDataSource());
   }
   }
   

4. 保存当前数据源

   public class DataSourceContextHolder {
   //默认的数据源
   public static final String DEFAULT_DB = "datasource1";
   
   private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();
   
   //设置数据源
   public static void setDB(String dbType){
   	System.out.println("切换到---" + dbType + "---数据源");
   	contextHolder.set(dbType);
   }
   
   //获取数据源
   public static String getDB(){
   	return (contextHolder.get());
   }
   
   //清除数据源
   public static void clearDB(){
   	contextHolder.remove();
   }
    }
   

5. 当前数据源

    public class DynamicDataSource extends AbstractRoutingDataSource {
   
   @Override
   protected Object determineCurrentLookupKey() {
   	System.out.println("数据源为---" + DataSourceContextHolder.getDB());
   	return DataSourceContextHolder.getDB();
   }
   }
   

6. 自定义注解

   @Retention(RetentionPolicy.RUNTIME)
   	@Target(ElementType.METHOD)
   	@Documented
   	 public @interface DataSource {
   		String value() default "datasource1";
   	 }
   

7. aop管理动态切换数据源

   @Aspect
   @Component
   @Order(-10)
   //@Order 值越小，优先级越高
   public class DynamicDataSourceAspect {
   
   @SuppressWarnings("rawtypes")
   @Before("@annotation(DataSource)")
   public void before(JoinPoint point){
   	
   	//获取当前访问的类名
   	Class<?> className = point.getTarget().getClass();
   	
   	//获取当前访问的方法名
   	String methodName = point.getSignature().getName();
   	
   	//获取方法的参数类型
   	Class[] argClass = ((MethodSignature)point.getSignature()).getParameterTypes();
   	
   	//默认数据源
   	String dataSource = DataSourceContextHolder.DEFAULT_DB;
   	
   	try {
   		//获取访问的方法对象
   		Method method = className.getMethod(methodName, argClass);
   		//判断是否存在@DataSource注解
   		if(method.isAnnotationPresent(DataSource.class)){
   			DataSource annotation = method.getAnnotation(DataSource.class);
   			//获取注解中指定的数据源
   			dataSource = annotation.value();
   		}
   	} catch (Exception e) {
   		e.printStackTrace();
   	} 
   	
   	//切换到指定的数据源
   	DataSourceContextHolder.setDB(dataSource);
   }
   
   @After("@annotation(DataSource)")
   public void after(JoinPoint point){
   	DataSourceContextHolder.clearDB();
   }
   
    }
   

切面处要添加注解@Order（-10），如果不使用，在使用@Transaction注解的时候，会使数据源的动态切换无效，始终只使用默认的数据源
8. 实体层

 @Data
@ToString
public class User {
	
	private Integer id;
	private String name;
	private Integer age;

}

这里我使用了Lombok插件，如果没有装插件的话，就把注释去掉，乖乖写getter，setter方法，建议可以去装一个

9. dao层

    public interface UserMapper {
   
   @Select("SELECT * FROM USER WHERE NAME = #{name}")
   public User findByName(@Param("name") String name);
   
   @Insert("INSERT INTO USER(NAME, AGE) VALUES(#{name}, #{age})")
   int insert(@Param("name") String name, @Param("age") Integer age);
   
    }
   

10. service层

@Service
public class UserService {
	
	@Autowired
	private UserMapper mapper;
	
	@DataSource("datasource1")
	@Transactional
	public int insertUser1(String name, Integer age){
		int result = mapper.insert(name, age);
		int i = 1 / age;
		return result;
	}
	
	@DataSource("datasource2")
	@Transactional
	public int insertUser2(String name, Integer age){
		int result = mapper.insert(name, age);
		int i = 1 / age;
		return result;
	}

}

11. controller层

@RestController
public class DataSourceController {
	
	@Autowired
	private UserService userService;
	
	@RequestMapping("/insert1")
	public Integer insert01(String name, Integer age){
		
		return userService.insertUser1(name, age);
	}
	
	@RequestMapping("/insert2")
	public Integer insert02(String name, Integer age){
		
		return userService.insertUser2(name, age);
	}

}

12. 启动类

@SpringBootApplication(exclude=DataSourceAutoConfiguration.class)
@MapperScan(basePackages="com.ma.springboot.mapper")
	 public class App {
	
	public static void main(String[] args) {
		SpringApplication.run(App.class, args);
	}

}

这里要在SpringBootApplication注解中标明exclude=DataSourceAutoConfiguration.class。不然的话，SpringBoot自动装载的事务会让项目无法启动