SpringBoot 多数据源配置

三个测试数据库SQL：

data01

-- ----------------------------
-- Table structure for tb_user
-- ----------------------------
DROP TABLE IF EXISTS `tb_user`;
CREATE TABLE `tb_user`  (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,
  `age` int(11) NULL DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of tb_user
-- ----------------------------
INSERT INTO `tb_user` VALUES (1, '001', 10);
INSERT INTO `tb_user` VALUES (2, '002', 20);

data02

DROP TABLE IF EXISTS `tb_user`;
CREATE TABLE `tb_user`  (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,
  `age` int(11) NULL DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 1 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of tb_user
-- ----------------------------
INSERT INTO `tb_user` VALUES (1, '003', 30);
INSERT INTO `tb_user` VALUES (2, '004', 40);

data03

DROP TABLE IF EXISTS `tb_user`;
CREATE TABLE `tb_user`  (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,
  `age` int(11) NULL DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 3 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of tb_user
-- ----------------------------
INSERT INTO `tb_user` VALUES (1, '005', 50);
INSERT INTO `tb_user` VALUES (2, '006', 60);

Pom.xml

• 这是刚新建SpringBoot项目的pom.xml依赖

<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>
        <scope>test</scope>
    </dependency>
</dependencies>

• 配置数据库和jdbc

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

• 配置spring-aop

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aop</artifactId>
</dependency>
<dependency>
    <groupId>org.aspectj</groupId>
    <artifactId>aspectjweaver</artifactId>
</dependency>

application.yml配置

spring:
  datasource:
    local:
      username: root
      password: 123456
      jdbc-url: jdbc:mysql://127.0.0.1:3306/data01?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
      driver-class-name: com.mysql.cj.jdbc.Driver
      enabled: true
    remote:
      username: root
      password: 123456
      jdbc-url: jdbc:mysql://127.0.0.1:3306/data02?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
      driver-class-name: com.mysql.cj.jdbc.Driver
    three:
      username: root
      password: 123456
      jdbc-url: jdbc:mysql://127.0.0.1:3306/data03?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
      driver-class-name: com.mysql.cj.jdbc.Driver
      enabled: true

注意：各个版本的 springboot 配置 datasource 时参数有所变化，例如低版本配置数据库 url时使用 url 属性，高版本使用 jdbc-url 属性

连接数据源配置文件

public enum DataSourceType {
    REMOTE,
    LOCAL,
    THREE
}

public class DynamicDataSourceContextHolder {

    /**
     * 使用ThreadLocal维护变量，ThreadLocal为每个使用该变量的线程提供独立的变量副本
     * 所以每个线程都可以独立的改变自己的副本，而不会影响其它线程所对应的副本
     */
    private static final ThreadLocal<String> CONTEXT_HOLDER = new ThreadLocal<>();

    /**
     * 设置数据源类型
     * @param dataSourceType
     */
    public static void setDataSource(String dataSourceType){
        System.out.printf("切换到{%s}数据源",dataSourceType);
        CONTEXT_HOLDER.set(dataSourceType);
    }

    /**
     * 获取数据源类型
     * @return
     */
    public static String getDataSourceType(){
        return CONTEXT_HOLDER.get();
    }

    /**
     * 清空数据源类型
     */
    public static void clearDataSourceType(){
        CONTEXT_HOLDER.remove();
    }
}

public class DynamicDataSource extends AbstractRoutingDataSource {

    public DynamicDataSource(DataSource defaultTargetDataSource, Map<Object,Object> targetDataSource){
        super.setDefaultTargetDataSource(defaultTargetDataSource);
        super.setTargetDataSources(targetDataSource);
        // afterPropertiesSet方法调用时用来将targetDataSource的属性写入resolvedDataSource中的
        super.afterPropertiesSet();
    }

    /**
     * 根据Key获取数据源信息
     * @return
     */
    @Override
    protected Object determineCurrentLookupKey() {
        return DynamicDataSourceContextHolder.getDataSourceType();
    }
}

@Configuration
public class DataSourceConfig {

    @Bean
    @ConfigurationProperties("spring.datasource.remote")
    public DataSource remoteDataSource(){
        return DataSourceBuilder.create().build();
    }

    @Bean
    @ConfigurationProperties("spring.datasource.local")
    @ConditionalOnProperty(prefix = "spring.datasource.local",name = "enabled",havingValue = "true")
    public DataSource localDataSource(){
        return DataSourceBuilder.create().build();
    }

    @Bean
    @ConfigurationProperties("spring.datasource.three")
    @ConditionalOnProperty(prefix = "spring.datasource.three",name = "enabled",havingValue = "true")
    public DataSource threeDataSource(){
        return DataSourceBuilder.create().build();
    }

    @Bean
    @Primary //自动装配时当出现多个Bean候选者时，被注解为@Primary的Bean将作为首选者，否则将抛出异常
    public DynamicDataSource dynamicDataSource(DataSource remoteDataSource,DataSource localDataSource,DataSource threeDataSource){
        Map<Object,Object> targetDataSources = new HashMap<>();
        targetDataSources.put(DataSourceType.REMOTE.name(),remoteDataSource);
        targetDataSources.put(DataSourceType.LOCAL.name(),localDataSource);
        targetDataSources.put(DataSourceType.THREE.name(),threeDataSource);
        return new DynamicDataSource(remoteDataSource,targetDataSources);
    }
}

自定义注解：

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataSource {

    DataSourceType value() default DataSourceType.REMOTE;
}

@Aspect
@Order(1)
@Component
public class DataSourceAspect {

    @Pointcut("@annotation(com.example.demo.mult.DataSource)")
    public void dsPointCut(){}

    @Around("dsPointCut()")
    public Object around(ProceedingJoinPoint point) throws Throwable{
        MethodSignature signature = (MethodSignature) point.getSignature();
        Method method = signature.getMethod();
        DataSource dataSource = method.getAnnotation(DataSource.class);
        if (null!=dataSource){
            DynamicDataSourceContextHolder.setDataSource(dataSource.value().name());
        }
        try {
            return point.proceed();
        }finally {
            // 销毁数据源，在执行方法之后
            DynamicDataSourceContextHolder.clearDataSourceType();
        }
    }
}

测试

@RestController
public class TestController {

    @Resource
    private JdbcTemplate jdbcTemplate;

    @GetMapping("/data1")
    @DataSource(value = DataSourceType.LOCAL)
    public List<Map<String, Object>> getData1(){
        return jdbcTemplate.queryForList("select * from tb_user");
    }

    @GetMapping("/data2")
    @DataSource(value = DataSourceType.REMOTE)
    public List<Map<String, Object>> getData2(){
        return jdbcTemplate.queryForList("select * from tb_user");
    }

    @GetMapping("/data3")
    @DataSource(value = DataSourceType.THREE)
    public List<Map<String, Object>> getData3(){
        return jdbcTemplate.queryForList("select * from tb_user");
    }
}