SpringBoot创建DynamicDataSource报错：请求的Bean正创建中，是否存在无法解决的循环依赖？

Hey there, that "requested bean is currently in creation" error is a classic circular dependency issue—let’s break down why this might be happening and how to fix it with your current setup.

Possible Root Causes #

First, let’s look at what could be triggering this:

• Your dynamicDataSource bean might be indirectly referenced by another component that depends on it (like a transaction manager, MyBatis SqlSessionFactory, or a repository using the dynamic data source), creating a loop.
• Spring’s auto-configuration might be interfering—if DataSourceAutoConfiguration tries to create a default data source that ends up depending on your dynamic one, that can cause a cycle.
• There could be an implicit self-dependency in your dynamic data source logic (e.g., initializing something in the bean’s constructor that requires the fully created dynamicDataSource itself).

Step-by-Step Solutions #

1. Break the Cycle with @Lazy Injection #

The simplest fix is often to use @Lazy to delay the initialization of dependent beans. Try adding it to the data source injections in your dynamicDataSource bean:

@Bean(name = "dynamicDataSource")
public DataSource dataSource(
    @Lazy @Qualifier("masterDataSource") DataSource masterDataSource,
    @Lazy @Qualifier("slaveDataSource") DataSource slaveDataSource
) {
    // Your dynamic data source routing logic here
}

@Lazy tells Spring to create a proxy instead of initializing the bean immediately, which breaks the circular reference chain.

2. Explicitly Define Bean Creation Order with @DependsOn #

While Spring usually handles dependency order automatically, you can enforce that masterDataSource and slaveDataSource are fully created before dynamicDataSource:

@Bean(name = "dynamicDataSource")
@DependsOn({"masterDataSource", "slaveDataSource"})
public DataSource dataSource(
    @Qualifier("masterDataSource") DataSource masterDataSource,
    @Qualifier("slaveDataSource") DataSource slaveDataSource
) {
    // Your logic here
}

This ensures the two slave/master beans are ready before the dynamic one starts initializing.

3. Exclude Conflicting Auto-Configuration #

If Spring’s default DataSourceAutoConfiguration is clashing with your custom setup, exclude it from your application class to prevent it from creating a default data source that might form a cycle:

@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
public class YourSpringBootApplication {
    public static void main(String[] args) {
        SpringApplication.run(YourSpringBootApplication.class, args);
    }
}

Note: If you do this, you’ll need to manually configure related beans like PlatformTransactionManager or SqlSessionFactory (if using MyBatis) to use your dynamicDataSource.

4. Check Your Dynamic Data Source Implementation #

If you’re using AbstractRoutingDataSource (the common base class for dynamic data sources), make sure you’re not triggering data source operations during initialization. Avoid calling methods that require a connection in the constructor—use @PostConstruct instead for any setup logic:

@Bean(name = "dynamicDataSource")
public DataSource dataSource(
    @Qualifier("masterDataSource") DataSource masterDataSource,
    @Qualifier("slaveDataSource") DataSource slaveDataSource
) {
    AbstractRoutingDataSource dynamicDS = new AbstractRoutingDataSource() {
        @Override
        protected Object determineCurrentLookupKey() {
            // Your routing logic here
        }
    };
    // Set target data sources
    dynamicDS.setTargetDataSources(Map.of("master", masterDataSource, "slave", slaveDataSource));
    dynamicDS.setDefaultTargetDataSource(masterDataSource);
    
    // Use @PostConstruct if you need to run initialization logic that uses the data source
    return dynamicDS;
}

Quick Check #

Double-check if any other beans (like transaction managers, JPA EntityManagerFactory, or DAOs) are referencing dynamicDataSource while that bean is still being created. If so, adding @Lazy to those references can also resolve the cycle.

内容的提问来源于stack exchange，提问作者ChangQi