Spring Boot 解决数据库宕机的连接重试问题的技术方案

Spring Boot生态中有多个优秀的开源中间件可以解决数据库连接问题。以下是常用的解决方案：

一、连接池层面的解决方案

1.HikariCP（内置，但需要正确配置）

虽然Spring Boot默认使用HikariCP，但需要正确配置才能发挥容错能力：

spring:datasource:hikari:connection-test-query:SELECT 1validation-timeout:5000keepalive-time:60000max-lifetime:600000connection-timeout:30000leak-detection-threshold:60000

2.Druid（阿里连接池）

<dependency><groupId>com.alibaba</groupId><artifactId>druid-spring-boot-starter</artifactId><version>1.2.20</version></dependency>

spring:datasource:druid:# 连接池配置initial-size:5min-idle:5max-active:20# 连接测试test-on-borrow:truetest-on-return:falsetest-while-idle:truevalidation-query:SELECT 1# 异常重连time-between-eviction-runs-millis:60000min-evictable-idle-time-millis:300000# 过滤器和监控filters:stat,wall,log4j2connection-properties:druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000

二、重试和容错框架

3.Spring Retry（官方）

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

@Configuration@EnableRetrypublicclassRetryConfig{}@ServicepublicclassUserService{@Retryable(value={DataAccessException.class,SQLException.class},maxAttempts=3,backoff=@Backoff(delay=1000,multiplier=2))publicUsergetUser(Longid){returnuserRepository.findById(id).orElse(null);}@RecoverpublicUserrecover(DataAccessExceptione,Longid){returnnewUser();// 降级处理}}

4.Resilience4j（轻量级容错库）

<dependency><groupId>io.github.resilience4j</groupId><artifactId>resilience4j-spring-boot2</artifactId><version>2.1.0</version></dependency>

resilience4j:circuitbreaker:instances:databaseService:registerHealthIndicator:trueslidingWindowSize:100failureRateThreshold:50waitDurationInOpenState:60spermittedNumberOfCallsInHalfOpenState:10automaticTransitionFromOpenToHalfOpenEnabled:truerecordExceptions:-org.springframework.dao.DataAccessException-java.sql.SQLException

@ServicepublicclassDatabaseService{@CircuitBreaker(name="databaseService",fallbackMethod="fallback")publicList<User>getUsers(){returnuserRepository.findAll();}publicList<User>fallback(Exceptione){returnnewArrayList<>();}}

三、数据源动态切换和故障转移

5.dynamic-datasource-spring-boot-starter（MyBatis-Plus官方）

<dependency><groupId>com.baomidou</groupId><artifactId>dynamic-datasource-spring-boot-starter</artifactId><version>3.6.1</version></dependency>

spring:datasource:dynamic:primary:masterstrict:falsedatasource:master:url:jdbc:mysql://localhost:3306/masterusername:rootpassword:123456slave_1:url:jdbc:mysql://localhost:3306/slave1username:rootpassword:123456slave_2:url:jdbc:mysql://localhost:3306/slave2username:rootpassword:123456hikari:connection-test-query:SELECT 1validation-timeout:5000max-lifetime:600000

@Service@DS("slave")// 使用从库publicclassUserServiceImplimplementsUserService{@Override@DS("master")// 强制使用主库publicvoidaddUser(Useruser){// 写操作}}

6.sharding-jdbc（分布式数据库中间件）

<dependency><groupId>org.apache.shardingsphere</groupId><artifactId>sharding-jdbc-spring-boot-starter</artifactId><version>4.1.1</version></dependency>

spring:shardingsphere:datasource:names:ds0,ds1ds0:type:com.zaxxer.hikari.HikariDataSourcedriver-class-name:com.mysql.cj.jdbc.Driverjdbc-url:jdbc:mysql://localhost:3306/db0username:rootpassword:123456ds1:type:com.zaxxer.hikari.HikariDataSourcedriver-class-name:com.mysql.cj.jdbc.Driverjdbc-url:jdbc:mysql://localhost:3306/db1username:rootpassword:123456masterslave:name:msmaster-data-source-name:ds0slave-data-source-names:ds1load-balance-algorithm-type:round_robin

四、缓存降级方案

7.Spring Cache + Redis/Caffeine

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

@Configuration@EnableCachingpublicclassCacheConfig{@BeanpublicCacheManagercacheManager(){CaffeineCacheManagercacheManager=newCaffeineCacheManager();cacheManager.setCaffeine(Caffeine.newBuilder().maximumSize(500).expireAfterAccess(600,TimeUnit.SECONDS));returncacheManager;}}@ServicepublicclassUserService{@Cacheable(value="users",unless="#result == null")publicUsergetUser(Longid){// 数据库查询returnuserRepository.findById(id).orElse(null);}@CachePut(value="users",key="#user.id")publicUsersaveUser(Useruser){returnuserRepository.save(user);}@CacheEvict(value="users",key="#id")publicvoiddeleteUser(Longid){userRepository.deleteById(id);}}

五、健康检查和监控

8.Spring Boot Actuator

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

management:endpoints:web:exposure:include:health,info,metricsendpoint:health:show-details:alwayshealth:db:enabled:trueredis:enabled:true

9.自定义健康检查

@ComponentpublicclassDatabaseHealthChecker{@AutowiredprivateDataSourcedataSource;@Scheduled(fixedDelay=30000)publicvoidcheckDatabase(){try(Connectionconn=dataSource.getConnection()){if(!conn.isValid(3)){// 触发告警notifyAlert("Database connection invalid");}}catch(SQLExceptione){notifyAlert("Database error: "+e.getMessage());}}}

六、完整解决方案推荐

最佳组合方案

<dependencies><!-- 1. 连接池：HikariCP + 正确配置 --><dependency><groupId>com.zaxxer</groupId><artifactId>HikariCP</artifactId></dependency><!-- 2. 重试机制：Spring Retry --><dependency><groupId>org.springframework.retry</groupId><artifactId>spring-retry</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-aop</artifactId></dependency><!-- 3. 断路器：Resilience4j --><dependency><groupId>io.github.resilience4j</groupId><artifactId>resilience4j-spring-boot2</artifactId><version>2.1.0</version></dependency><!-- 4. 多数据源：dynamic-datasource --><dependency><groupId>com.baomidou</groupId><artifactId>dynamic-datasource-spring-boot-starter</artifactId><version>3.6.1</version></dependency><!-- 5. 缓存：Caffeine --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-cache</artifactId></dependency><!-- 6. 监控：Actuator --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-actuator</artifactId></dependency></dependencies>

配置文件示例

spring:# 数据源配置datasource:dynamic:primary:masterstrict:falsedatasource:master:url:jdbc:mysql://localhost:3306/master?autoReconnect=trueusername:rootpassword:123456driver-class-name:com.mysql.cj.jdbc.Driverslave:url:jdbc:mysql://localhost:3306/slave?autoReconnect=trueusername:rootpassword:123456driver-class-name:com.mysql.cj.jdbc.Driverhikari:connection-test-query:SELECT 1validation-timeout:5000keepalive-time:60000max-lifetime:600000connection-timeout:30000# 缓存配置cache:type:caffeinecaffeine:spec:maximumSize=500,expireAfterAccess=600s# 重试配置resilience4j:circuitbreaker:instances:databaseService:failure-rate-threshold:50wait-duration-in-open-state:60spermitted-number-of-calls-in-half-open-state:10sliding-window-size:100# 监控配置management:endpoints:web:exposure:include:health,info,metricsendpoint:health:show-details:always

使用示例

@Service@Slf4jpublicclassUserService{@AutowiredprivateUserMapperuserMapper;@AutowiredprivateCacheManagercacheManager;@CircuitBreaker(name="databaseService",fallbackMethod="getUserFromCache")@Retryable(value={DataAccessException.class},maxAttempts=3)@DS("slave")// 读操作使用从库publicUsergetUser(Longid){returnuserMapper.selectById(id);}@DS("master")// 写操作使用主库@Retryable(value={DataAccessException.class},maxAttempts=3)publicvoidsaveUser(Useruser){userMapper.insert(user);// 更新缓存cacheManager.getCache("users").put(user.getId(),user);}// 降级方法privateUsergetUserFromCache(Longid,Exceptione){log.warn("Fallback to cache for user id: {}",id,e);Cachecache=cacheManager.getCache("users");if(cache!=null){Cache.ValueWrapperwrapper=cache.get(id);if(wrapper!=null){return(User)wrapper.get();}}returnnull;}}

总结

这些开源中间件各有特点：

推荐组合：HikariCP + Spring Retry + Resilience4j + dynamic-datasource + Caffeine，这个组合能提供完整的数据库容错能力。