@SpringBootApplication
public class Main {
    public static void main(String[] args) {
        SpringApplication.run(Main.class,args);
    }
}

@RestController
public class HelloController {
    @RequestMapping(value = "/hello")
    public String hello(){
        return "hello world!";
    }
}

@SpringBootApplication
public class Main {
    public static void main(String[] args) {
        SpringApplication.run(Main.class,args);
    }
}

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@SpringBootConfiguration //Spring Boot配置类，里面有@Configuration注解，类似以前的xml配置
@EnableAutoConfiguration //开启自动配置功能
@ComponentScan(excludeFilters = {
        @Filter(type = FilterType.CUSTOM, classes = TypeExcludeFilter.class),
        @Filter(type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class) })
public @interface SpringBootApplication {

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@AutoConfigurationPackage //自动配置包
@Import(AutoConfigurationImportSelector.class) //导入配置选择器
public @interface EnableAutoConfiguration {

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@Import(AutoConfigurationPackages.Registrar.class)
public @interface AutoConfigurationPackage {

/**
 * 将配置文件中配置的每一个属性的值，映射到这个 javaBean 组件中
 * @ConfigurationProperties：告诉SpringBoot将本类中的所有属性和配置文件中相关的配置进行绑定
 * prefix = "person"：配置文件中哪个下面的所有属性进行一一映射
 * 只有这个组件是容器中的组件，才能容器提供的@ConfigurationProperties功能
 */
@Component
@ConfigurationProperties(prefix = "person")
public class Person {
    private String lastName;
    private Integer age;
    private Boolean boss;
    private Date birth;
    private Map<String,Object> maps;
    private List<Object> lists;
    private Dog dog;

# 配置文件注入值数据校验
@Component
@ConfigurationProperties(prefix = "person")
@Validated
public class Person {
    //lastName必须是邮箱格式
    @Email
    //@Value("${person.last-name}")
    private String lastName;
    //@Value("#{11*2}")
    private Integer age;
    //@Value("true")
    private Boolean boss;

/**
 * @ConfigurationProperties：将本类中的所有属性和 全局配置文件 中相关的配置进行绑定
 * prefix = "person"：配置文件中哪个下面的所有属性进行一一映射
 * 只有这个组件是容器中的组件，才能容器提供的@ConfigurationProperties功能；
 */
@Component
@ConfigurationProperties(prefix = "person")
@PropertySource(value = {"classpath:person.properties"})
public class Person {
    //@Value("${person.last-name}")
    private String lastName;
    //@Value("#{11*2}")
    private Integer age;
    //@Value("true")
    private Boolean boss;

# 导入Spring的xml配置文件让其生效
@ImportResource(locations = {"classpath:beans.xml"})

// @Configuration：指明当前类是一个配置类
@Configuration
public class MyAppConfig {
    //将方法的返回值添加到容器中，容器中这个组件默认的id就是方法名
    @Bean
    public HelloService helloService02(){
        System.out.println("配置类@Bean给容器中添加组件了...");
        return new HelloService();
    }
}

${random.value}
${random.int}
${random.long}
${random.int(10)}
${random.int[1024,65536]}

@Configuration //表示是一个配置类，和以前编写的配置文件一样，也可以给容器中添加组件
@EnableConfigurationProperties(HttpEncodingProperties.class) //启动指定类的ConfigurationProperties功能，将配置文件中对应的值和HttpEncodingProperties绑定起来；并把HttpEncodingProperties加入到ioc容器中
@ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.SERVLET) //Spring底层@Conditional注解，根据不同的条件来确定是否添加到容器中，判断当前应用是否是web应用，如果是，当前配置类生效
@ConditionalOnClass(CharacterEncodingFilter.class) //判断当前项目有没有这个类CharacterEncodingFilter，它是SpringMVC中进行乱码解决的过滤器
@ConditionalOnProperty(prefix = "spring.http.encoding", value = "enabled", matchIfMissing = true) //判断配置文件中是否存在某个配置  spring.http.encoding.enabled；如果不存在，判断也是成立的，即使我们配置文件中不配置pring.http.encoding.enabled=true，也是默认生效的；
public class HttpEncodingAutoConfiguration {

    //SpringBoot的配置文件的映射类
    private final HttpEncodingProperties properties;

    //只有一个有参构造器的情况下，参数的值就会从容器中拿
    public HttpEncodingAutoConfiguration(HttpEncodingProperties properties) {
        this.properties = properties;
    }

    @Bean  //给容器中添加一个组件，这个组件的某些值需要从properties中获取
    @ConditionalOnMissingBean //判断容器是否没有这个组件
    public CharacterEncodingFilter characterEncodingFilter() {
        CharacterEncodingFilter filter = new OrderedCharacterEncodingFilter();
        filter.setEncoding(this.properties.getCharset().name());
        filter.setForceRequestEncoding(this.properties.shouldForce(Type.REQUEST));
        filter.setForceResponseEncoding(this.properties.shouldForce(Type.RESPONSE));
        return filter;
    }

    @Bean
    public LocaleCharsetMappingsCustomizer localeCharsetMappingsCustomizer() {
        return new LocaleCharsetMappingsCustomizer(this.properties);
    }

    private static class LocaleCharsetMappingsCustomizer implements WebServerFactoryCustomizer<ConfigurableServletWebServerFactory>, Ordered {

        private final HttpEncodingProperties properties;

        LocaleCharsetMappingsCustomizer(HttpEncodingProperties properties) {
            this.properties = properties;
        }

        @Override
        public void customize(ConfigurableServletWebServerFactory factory) {
            if (this.properties.getMapping() != null) {
                factory.setLocaleCharsetMappings(this.properties.getMapping());
            }
        }

        @Override
        public int getOrder() {
            return 0;
        }

    }

}

@ConfigurationProperties(prefix = "spring.http.encoding") //从配置文件中获取指定的值和bean的属性进行绑定
public class HttpEncodingProperties {

    public static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;