Spring Boot系列笔记--HelloWorld

一、编写helloworld过程

创建maven工程（jar）导入springboot相关依赖<parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.9.RELEASE</version> </parent> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> </dependencies> 编写主程序/** * @SpringBootApplication 来标注一个主程序类，说明这是一个Spring Boot应用 */ @SpringBootApplication public class HelloWorldMainApplication { public static void main(String[] args) { // Spring应用启动起来 SpringApplication.run(HelloWorldMainApplication.class,args); } } 编写相关controller、service@Controller public class HelloController { @ResponseBody @RequestMapping("/hello") public String hello(){ return "Hello World!"; } } 运行简化部署<!-- 这个插件，可以将应用打包成一个可执行的jar包；--> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build>

二、注解细节

@SpringBootApplication 进入该注解：@Target({ElementType.TYPE}) @Retention(RetentionPolicy.RUNTIME) @Documented @Inherited /** * @SpringBootConfiguration : Spring Boot的配置类 */ @SpringBootConfiguration /** * @EnableAutoConfiguration : 开启自动配置功能 */ @EnableAutoConfiguration @ComponentScan( excludeFilters = {@Filter( type = FilterType.CUSTOM, classes = {TypeExcludeFilter.class} ), @Filter( type = FilterType.CUSTOM, classes = {AutoConfigurationExcludeFilter.class} )} ) 进入@EnableAutoConfiguration注解：@AutoConfigurationPackage //自动配置包 @Import({AutoConfigurationImportSelector.class}) @Import注解将主配置类（@SpringBootApplication标注的类）的所在包及下面所有子包里面的所 有组件扫描到Spring容器@RestController 该注解是@ResponseBody和@Controller的结合体