详解Java如何使用注解来配置Spring容器

@Configuration
public class AppConfig {
    @Bean
    public MyService myService() {
        return new MyServiceImpl();
    } 
    @Bean
    public OtherService otherService() {
        return new OtherService();
    }
}

public static void main(String[] args) {
    ApplicationContext ctx = new AnnotationConfigApplicationContext(AppConfig.class);
    MyService myService = ctx.getBean(MyService.class);
    myService.doStuff();
}

public static void main(String[] args) {
    AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
    ctx.register(AppConfig.class, OtherConfig.class);
    ctx.register(AdditionalConfig.class);
    ctx.refresh();
    MyService myService = ctx.getBean(MyService.class);
    myService.doStuff();
}

@Configuration
@ComponentScan(basePackages = "com.acme") 
public class AppConfig  {
    // ...
}

@Configuration
public class AppConfig {
    @Bean
    public TransferService transferService(AccountRepository accountRepository) {
        return new TransferServiceImpl(accountRepository);
    }
}

public class BeanOne {

    public void init() {
        // initialization logic
    }
}
public class BeanTwo {

    public void cleanup() {
        // destruction logic
    }
}
@Configuration
public class AppConfig {

    @Bean(initMethod = "init")
    public BeanOne beanOne() {
        return new BeanOne();
    }
    @Bean(destroyMethod = "cleanup")
    public BeanTwo beanTwo() {
        return new BeanTwo();
    }
}

@Configuration
public class MyConfiguration {
    @Bean
    @Scope("prototype")
    public Encryptor encryptor() {
        // ...
    }
}

@Configuration
public class AppConfig {
    @Bean("myThing")
    public Thing thing() {
        return new Thing();
    }
}

@Configuration
public class AppConfig {
    @Bean({"dataSource", "subsystemA-dataSource", "subsystemB-dataSource"})
    public DataSource dataSource() {
        // instantiate, configure and return DataSource bean...
    }
}

@Configuration
public class AppConfig {
    @Bean
    public BeanOne beanOne() {
        return new BeanOne(beanTwo());
    }
    @Bean
    public BeanTwo beanTwo() {
        return new BeanTwo();
    }
}

@Configuration
public class ConfigA {
    @Bean
    public A a() {
        return new A();
    }
}
@Configuration
@Import(ConfigA.class)
public class ConfigB {
    @Bean
    public B b() {
        return new B();
    }
}

public static void main(String[] args) {
    ApplicationContext ctx = new AnnotationConfigApplicationContext(ConfigB.class);
    // now both beans A and B will be available...
    A a = ctx.getBean(A.class);
    B b = ctx.getBean(B.class);
}

@Configuration
@ImportResource("classpath:/com/acme/properties-config.xml")
public class AppConfig {
    @Value("${jdbc.url}")
    private String url;
    @Value("${jdbc.username}")
    private String username;
    @Value("${jdbc.password}")
    private String password;
    @Bean
    public DataSource dataSource() {
        return new DriverManagerDataSource(url, username, password);
    }
}

<!-- properties-config.xml -->
<beans>
    <context:property-placeholder location="classpath:/com/acme/jdbc.properties"/>
</beans>

@Configuration
@PropertySource("classpath:config.properties")
public class ProperySourceDemo implements InitializingBean {
    @Autowired
    Environment env;
    @Override
    public void afterPropertiesSet() throws Exception {
        setDatabaseConfig();
    }
    private void setDatabaseConfig() {
        DataSourceConfig config = new DataSourceConfig();
        config.setDriver(env.getProperty("jdbc.driver"));
        config.setUrl(env.getProperty("jdbc.url"));
        config.setUsername(env.getProperty("jdbc.username"));
        config.setPassword(env.getProperty("jdbc.password"));
        System.out.println(config.toString());
    }
}

@Configuration
 @PropertySources({
  @PropertySource("classpath:config.properties"),
  @PropertySource("classpath:db.properties")
 })
 public class AppConfig {
  //...
 }

account.name=TestAccount

@Configuration
public class AppConfig {
    @Bean
    public MessageSource messageSource() {
      ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
      messageSource.setBasename("config/messages");
      return messageSource;
    }
}

@Service
public class AccountService {
    @Autowired
    private MessageSource messageSource;
    
    public void someMsg() {
        messageSource.getMessage("account.name", null, Locale.ENGLISH);
        //todo
    }
}