一. 假设有如下三个类实现同一个接口,则自动装配时会产生歧义 @Component public class Cake implements Dessert { ... } @Component public class Cookies implements Dessert { ... } @Component public class IceCream implements Dessert { ... } @Autowired public void setDessert(Dessert de…

1.When injecting properties and constructor arguments on beans that are created via component-scanning, you can use the @Value annotation, much as you saw earlierwith property placeholders. Rather than use a placeholder expression, however, youuse a…

一. The @Qualifier annotation is the main way to work with qualifiers. It can beapplied alongside @Autowired or @Inject at the point of injection to specify whichbean you want to be injected. For example, let’s say you want to ensure that theIceCream…

一. Spring的bean默认是单例的 But sometimes you may find yourself working with a mutable class that does main-tain some state and therefore isn’t safe for reuse. In that case, declaring the class as asingleton bean probably isn’t a good idea because that obje…

一. 1.SpEL expressions are framed with  #{ ... } 2.SpEl的作用 Sp EL has a lot of tricks up its sleeves, including the following: The ability to reference beans by their ID s Invoking methods and accessing properties on objects Mathematical, relational…

一.用placeholder给bean运行时注入值的步骤 Spring取得placeholder的值是用${...} 1.声明placeholder bean (1)java方式 In order to use placeholder values, you must configure either a PropertyPlaceholder-Configurer bean or a PropertySourcesPlaceholderConfigurer bean. Starting wit…

一. 直观的给bean注入值如下: @Bean public CompactDisc sgtPeppers() { return new BlankDisc( "Sgt. Pepper's Lonely Hearts Club Band", "The Beatles"); } < bean id = "sgtPeppers" class = "soundsystem.BlankDisc" c: _title = &quo…

一. Spring honors two separate properties when determining which profiles are active:spring.profiles.active and spring.profiles.default . If spring.profiles.activeis set, then its value determines which profiles are active. But if spring.profiles.acti…

一. DataSource在应用和开发环境的产生方式不同,可以用srping 的profile管理 Spring’s solution for environment-specific beans isn’t much different from build-timesolutions. Certainly, an environment-specific decision is made as to which beans willand won’t be created. But rath…

一.用@Conditional根据条件决定是否要注入bean 1. package com.habuma.restfun; public class MagicBean { } 2. package com.habuma.restfun; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Conditional; import org.springfr…