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# Auto-Configuration
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The Druid Spring Boot Starter provides automatic configuration for Druid DataSource integration through Spring Boot's auto-configuration mechanism.
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## Capabilities
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### DruidDataSourceAutoConfigure
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Main auto-configuration class that conditionally creates and configures Druid DataSource beans when appropriate conditions are met.
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```java { .api }
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/**
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 * Auto-configuration for Druid DataSource integration
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 * Conditionally creates DruidDataSourceWrapper when:
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 * - spring.datasource.type is set to DruidDataSource or not specified
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 * - DruidDataSource class is available on classpath  
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 * - No existing DataSource beans are present
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 */
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@Configuration
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@ConditionalOnProperty(name = "spring.datasource.type", havingValue = "com.alibaba.druid.pool.DruidDataSource", matchIfMissing = true)
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@ConditionalOnClass(DruidDataSource.class)
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@AutoConfigureBefore(DataSourceAutoConfiguration.class)
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@EnableConfigurationProperties({DruidStatProperties.class, DataSourceProperties.class})
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@Import({DruidSpringAopConfiguration.class, DruidStatViewServletConfiguration.class, DruidWebStatFilterConfiguration.class, DruidFilterConfiguration.class})
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public class DruidDataSourceAutoConfigure {
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    /**
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     * Creates the primary DruidDataSourceWrapper bean when no other DataSource beans exist
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     * @return DruidDataSourceWrapper configured with Spring Boot properties
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     */
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    @Bean
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    @ConditionalOnMissingBean({DruidDataSourceWrapper.class, DruidDataSource.class, DataSource.class})
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    public DruidDataSourceWrapper dataSource();
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}
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```
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**Key Features:**
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- **Conditional Activation**: Only activates when `spring.datasource.type` is set to Druid or not specified
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- **Class Path Detection**: Requires DruidDataSource class to be available 
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- **Bean Conflict Prevention**: Won't create DataSource if one already exists
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- **Property Integration**: Automatically binds `DruidStatProperties` and `DataSourceProperties`
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- **Component Import**: Imports all related configuration classes for monitoring, AOP, and filters
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**Usage Example:**
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The auto-configuration activates automatically when you add the starter dependency. To ensure it activates, either:
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1. Don't specify `spring.datasource.type` (it will default to Druid)
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2. Explicitly set it:
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```properties
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spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
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```
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### Configuration Properties Integration
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The auto-configuration enables two main property classes:
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```java { .api }
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/**
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 * Standard Spring Boot DataSource properties
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 * Used as fallback when Druid-specific properties are not set
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 */
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@EnableConfigurationProperties(DataSourceProperties.class)
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/**
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 * Druid-specific configuration properties  
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 * Takes precedence over standard DataSource properties
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 */
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@EnableConfigurationProperties(DruidStatProperties.class)
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```
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### Component Import Strategy
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The auto-configuration uses `@Import` to conditionally include related configuration:
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```java { .api }
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@Import({
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    DruidSpringAopConfiguration.class,      // AOP monitoring integration
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    DruidStatViewServletConfiguration.class, // Web monitoring console
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    DruidWebStatFilterConfiguration.class,   // Web statistics filter
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    DruidFilterConfiguration.class          // Various Druid filters
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})
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```
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Each imported configuration class has its own conditional logic, so they only activate when their specific conditions are met.
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### Auto-Configuration Ordering
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The configuration is explicitly ordered to run before Spring Boot's default DataSource auto-configuration:
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```java { .api }
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@AutoConfigureBefore(DataSourceAutoConfiguration.class)
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```
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This ensures that if Druid conditions are met, the Druid DataSource will be created instead of Spring Boot's default DataSource.
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### Conditional Logic Summary
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The auto-configuration will create a DruidDataSourceWrapper bean when ALL of the following conditions are true:
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1. **Property Condition**: `spring.datasource.type` is either unset or set to `com.alibaba.druid.pool.DruidDataSource`
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2. **Class Condition**: `DruidDataSource.class` is available on the classpath
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3. **Bean Condition**: No existing beans of type `DruidDataSourceWrapper`, `DruidDataSource`, or `DataSource` are present
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**Configuration Override:**
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If you need to disable the auto-configuration entirely, you can exclude it:
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```java
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@SpringBootApplication(exclude = DruidDataSourceAutoConfigure.class)
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public class Application {
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    // ...
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}
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```
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Or in `application.properties`:
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```properties
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spring.autoconfigure.exclude=com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceAutoConfigure
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```