springboot_基础笔记

怎么搭建一个简单的springboot

版本1.4.0

第一步新建一个maven工程

修改pom文件

    <!--添加父节点-->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.0.RELEASE</version>
    </parent>

    <!--添加依赖-->
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
    </dependencies>

新建一个启动类

@SpringBootApplication
public class App {
    @Bean
    public Book getBook() {
        return new Book();
    }

    public static void main(String[] args) {
        ConfigurableApplicationContext context = SpringApplication.run(App.class, args);
        User user = context.getBean(User.class);
        System.out.println("user = " + user);
        Book book = context.getBean(Book.class);
        System.out.println("book = " + book);
    }
}

这样就完成了

如果你的工程已经有了父节点

那么久使用

<dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>1.4.0.RELEASE</version>
                <scope>import</scope>
                <type>pom</type>
            </dependency>
        </dependencies>
    </dependencyManagement>

分析:

@SpringBootApplication注解包含了其他注解

@SpringBootConfiguration
@EnableAutoConfiguration
@ComponentScan(
    excludeFilters = {@Filter(
    type = FilterType.CUSTOM,
    classes = {TypeExcludeFilter.class}
)}
)

@SpringBootConfiguration:springboot的配置类注解

@EnableAutoConfiguration:新特性的注解

@ComponentScan:包扫描的注解

SpringApplication.run(App.class, args)会把App.class 包装成一个配置类

启动类的另外一种写法

//    public static void main(String[] args) {
//        SpringApplication application = new SpringApplication(App.class);
//        ConfigurableApplicationContext context = application.run(args);
//
//        Book book = context.getBean(Book.class);
//        System.out.println("book = " + book);
//
//    }