如何优化SpringBoot的项目的启动速度

日常开发SpringBoot项目启动类都用@SpringBootApplication，实际上它是下面三个注解的组合：

• @EnableAutoConfiguration: enable Spring Boot’s auto-configuration mechanism
• @ComponentScan: enable @Component scan on the package where the application is located (see the best practices)
• @Configuration: allow to register extra beans in the context or import additional configuration classes

启动慢往往跟@ComponentScan和@EnableAutoConfiguration加载的内容太多有关，一种方法是不用这两个注解，通过@import注解精确指定要加载扫描的类，但要加载的类多时又很麻烦，

可以用@SpringBootApplication注解下面的属性：

• exclude: Exclude the list of classes from the auto configuration.
• excludeNames: Exclude the list of fully qualified class names from the auto configuration. This parameter added since spring boot 1.3.0.
• scanBasePackageClasses: Provide the list of classes that has to be applied for the @ComponentScan.
• scanBasePackages Provide the list of packages that has to be applied for the @ComponentScan. This parameter added since spring boot 1.3.0.

另外，如果SpringBoot项目启动很慢，可能意味着你要重新拆分微服务。