以下是一个完整的Spring Boot自动配置实现示例，包含详细步骤和代码实现：
一、项目结构
my-starter/
├── my-spring-boot-autoconfigure/
│ ├── src/main/java/
│ │ └── com/example/autoconfigure/
│ │ ├── MyServiceAutoConfiguration.java # 自动配置类
│ │ ├── MyServiceProperties.java # 配置属性类
│ │ └── service/
│ │ └── MyService.java # 业务服务类
│ └── src/main/resources/
│ ├── META-INF/
│ │ ├── spring.factories # 自动配置注册文件
│ │ └── additional-spring-configuration-metadata.json # 元数据提示
├── my-spring-boot-starter/ # Starter模块
│ └── pom.xml
└── pom.xml
二、具体实现步骤
1. 创建配置属性类
// MyServiceProperties.java
@ConfigurationProperties(prefix = "my.service")
public class MyServiceProperties {
private String prefix = "[INFO]";
private boolean enabled = true;
// Getter/Setter 省略...
}
2. 创建业务服务类
// MyService.java
public class MyService {
private final String prefix;
public MyService(String prefix) {
this.prefix = prefix;
}
public String wrap(String content) {
return prefix + " " + content;
}
}
3. 创建自动配置类
// MyServiceAutoConfiguration.java
@Configuration
@EnableConfigurationProperties(MyServiceProperties.class)
@ConditionalOnClass(MyService.class)
@ConditionalOnProperty(prefix = "my.service", name = "enabled", havingValue = "true", matchIfMissing = true)
@AutoConfigureAfter(DataSourceAutoConfiguration.class) // 示例依赖
public class MyServiceAutoConfiguration {
private final MyServiceProperties properties;
public MyServiceAutoConfiguration(MyServiceProperties properties) {
this.properties = properties;
}
@Bean
@ConditionalOnMissingBean
public MyService myService() {
return new MyService(properties.getPrefix());
}
}
4. 注册自动配置
# src/main/resources/META-INF/spring.factories
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
com.example.autoconfigure.MyServiceAutoConfiguration
5. 添加配置元数据提示
# src/main/resources/META-INF/additional-spring-configuration-metadata.json
{
"properties": [
{
"name": "my.service.prefix",
"type": "java.lang.String",
"description": "Custom prefix for service output",
"defaultValue": "[INFO]"
},
{
"name": "my.service.enabled",
"type": "java.lang.Boolean",
"description": "Enable/disable my service",
"defaultValue": true
}
]
}
三、创建Starter模块（可选）
<!-- my-spring-boot-starter/pom.xml -->
<dependencies>
<dependency>
<groupId>com.example</groupId>
<artifactId>my-spring-boot-autoconfigure</artifactId>
<version>${project.version}</version>
</dependency>
</dependencies>
四、使用自动配置
# application.yml
my:
service:
prefix: "[DEBUG]"
enabled: true
// 在Spring Boot应用中直接注入
@RestController
public class DemoController {
private final MyService myService;
public DemoController(MyService myService) {
this.myService = myService;
}
@GetMapping("/test")
public String test() {
return myService.wrap("Hello World");
}
}
五、验证配置生效
- 启动时查看日志：
2023-09-20 10:00:00 INFO o.s.b.a.s.s.MyServiceAutoConfiguration : MyService auto-configured with prefix: [DEBUG] - 访问端点验证：
$ curl http://localhost:8080/test # 输出: [DEBUG] Hello World六、测试用例
@SpringBootTest class MyServiceAutoConfigurationTest { @Autowired(required = false) private MyService myService; @Test void testAutoConfiguration() { assertThat(myService).isNotNull(); assertThat(myService.wrap("test")).startsWith("[DEBUG]"); } @Test @EnabledIfProperty( name = "my.service.enabled", havingValue = "false" ) void testDisabledScenario() { assertThat(myService).isNull(); } }七、注意事项
- 包路径隔离：自动配置类应该放在不会被组件扫描的独立包中
- 条件注解顺序：
@ConditionalOnBean和@ConditionalOnMissingBean要谨慎使用 - 配置优先级：用户自定义Bean会覆盖自动配置的Bean
- 元数据校验：建议添加
spring-boot-configuration-processor依赖 完整实现需要包含以下依赖： ```xml
```
