SpringBoot整合Mybatis多数据源 (AOP+注解)

SpringBoot整合Mybatis多数据源 (AOP+注解)

1、pom.xml文件(开发用的JDK 10)

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>10</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- alibaba的druid数据库连接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.10</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>

        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
        </dependency>

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.0</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>

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

        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.3</version>
        </dependency>

        <!-- 热部署 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

2、多数据源配置类

@Configuration
public class DataSourceConfig {

    @Bean(name = "readTestDb")
    @ConfigurationProperties(prefix = "spring.datasource.read-test-db")
    public DataSource readTestDb() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "writeTestDb")
    @ConfigurationProperties(prefix = "spring.datasource.write-test-db")
    public DataSource writeTestDb() {
        return DataSourceBuilder.create().build();
    }

    /**
     * 动态数据源: 通过AOP在不同数据源之间动态切换
     * @return
     */
    @Primary
    @Bean(name = "dynamicDataSource")
    public DataSource dynamicDataSource() {
        DynamicDataSource dynamicDataSource = new DynamicDataSource();
        // 默认数据源
        dynamicDataSource.setDefaultTargetDataSource(readTestDb());
        // 配置多数据源
        Map<Object, Object> dsMap = new HashMap<Object, Object>();
        dsMap.put("readTestDb", readTestDb());
        dsMap.put("writeTestDb", writeTestDb());

        dynamicDataSource.setTargetDataSources(dsMap);
        return dynamicDataSource;
    }

    /**
     * 配置@Transactional注解事物
     * @return
     */
    @Bean
    public PlatformTransactionManager transactionManager() {
        return new DataSourceTransactionManager(dynamicDataSource());
    }

3、数据源切换读取类

public class DataSourceContextHolder {

    /**
     * 默认数据源
     */
    public static final String DEFAULT_DS = "readTestDb";

    private static final ThreadLocal<String> contextHolder = new ThreadLocal<>();

    // 设置数据源名
    public static void setDB(String dbType) {
        System.out.println("切换到{"+dbType+"}数据源");
        contextHolder.set(dbType);
    }

    // 获取数据源名
    public static String getDB() {
        return (contextHolder.get());
    }

    // 清除数据源名
    public static void clearDB() {
        contextHolder.remove();
    }

}

4、注解类(注意：要和配置类放在同一个包下，否则会抛出找不到注解异常)

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

5、动态数据源(设置数据源自动调用该类方法)

public class DynamicDataSource extends AbstractRoutingDataSource  {

    @Override
    protected Object determineCurrentLookupKey() {
        System.out.println("数据源为"+DataSourceContextHolder.getDB());
        return DataSourceContextHolder.getDB();
    }

}

6、AOP

@Aspect
@Component
public class DynamicDataSourceAspect {

    @Before("@annotation(DS)")
    @SuppressWarnings("rawtypes")
    public void beforeSwitchDS(JoinPoint point){
        //获得当前访问的class
        Class<?> className = point.getTarget().getClass();
        //获得访问的方法名
        String methodName = point.getSignature().getName();
        //得到方法的参数的类型
        Class[] argClass = ((MethodSignature)point.getSignature()).getParameterTypes();
        String dataSource = DataSourceContextHolder.DEFAULT_DS;
        try {
            // 得到访问的方法对象
            Method method = className.getMethod(methodName, argClass);
            // 判断是否存在@DS注解
            if (method.isAnnotationPresent(DS.class)) {
                DS annotation = method.getAnnotation(DS.class);
                // 取出注解中的数据源名
                dataSource = annotation.value();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        // 切换数据源
        DataSourceContextHolder.setDB(dataSource);
    }

    @After("@annotation(DS)")
    public void afterSwitchDS(JoinPoint point){
        DataSourceContextHolder.clearDB();
    }
}

7、application.yml 配置文件 (和application.properties区别 可以百度一下 很详细)

spring:
    datasource:
        read-test-db:
            jdbc-url: jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf-8
            username: root
            password: root
            # 使用druid数据源
            type: com.alibaba.druid.pool.DruidDataSource
            driver-class-name: com.mysql.jdbc.Driver

        write-test-db:
            jdbc-url: jdbc:mysql://127.0.0.1:3306/writetest?useUnicode=true&characterEncoding=utf-8
            username: root
            password: root
            # 使用druid数据源
            type: com.alibaba.druid.pool.DruidDataSource
            driver-class-name: com.mysql.jdbc.Driver
    jpa:
      show-sql: true

mybatis:
  #mapper-locations: classpath:mapping/mapper/*.xml
  type-aliases-package: com.example.demo.model

8、启动类( 注解：@MapperScan 扫描mapper接口类路径 、多数据源 @SpringBootApplication这个注解是必须写的 )

@MapperScan("com.example.demo.mapper")
@SpringBootApplication(exclude = {
        DataSourceAutoConfiguration.class
})
public class DemoApplication {

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

9、Controller( 注解：@RestController( 包含@controller、@responseBody等其他注解 所以用该注解就不用每个方法上@responseBody ) )

@RestController
public class DemoController {

    @Autowired
    private UserService userService;

    @RequestMapping("/getRequestDBObj")
    public User getRequestDBObj(HttpServletRequest request,HttpServletResponse response) {
        return userService.selectByPrimaryKey(1);
    }

    @RequestMapping("/getRequestDbList")
    public User getRequestDbList(HttpServletRequest request,HttpServletResponse response) {
        return userService.selectAllUser(1);
    }
}

10、Service

public interface UserService {

    public User selectByPrimaryKey(Integer userId);

    public User selectAllUser(Integer userId);
}

11、ServiceImpl

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserMapper userMapper;

    @Override
    @DS("writeTestDb")
    public User selectByPrimaryKey(Integer userId) {
        return userMapper.selectByPrimaryKey(userId);
    }

    @Override
    @DS("readTestDb")
    public User selectAllUser(Integer userId) {
        return userMapper.selectByPrimaryKey(userId);
    }

}

12、Mapper

public interface UserMapper {

    @Select("SELECT user_id as userId, user_name as userName, password, phone FROM t_user WHERE user_id = #{userId}")
    User selectByPrimaryKey(Integer userId);

}

13、本人 QQ 1036943655 本人萌新 有代码不对的地方 大家指教一下 也可以加好友 大家一起互相学习、互相进步