spring学习---2

参考书籍《spring in action》

1.装载bean

依赖注入的本质是装配（wiring），指的是创建应用对象之间协作关系的行为。

装配方式：

1）传统：XML should not be first choice

核心框架的10个命名空间：

<aop>

<beans>

<context>

<jee>

<jms>

<lang>

<mvc>

<oxm>

<tx>

<util> constant/list/map/properties/property-path/set

 

2）explicit configuration in java

step1：creating a configuration class
@Configuration
public class CDPlayerConfig{...}

step2:declaring a simple bean
@Bean(name="newname")
public CompactDisc sgtPeppers(){
     return new SgtPeppers();
}

step3 injecting with javaConfig
@Bean
public CDPlayer cdPlayer(){
   return new CDPlayer(sgtPeppers());
}

3 ) implicit bean discovery and automatic wiring（只有自己写的源代码可以用）

##compoent scanning---在应用上下文中自动发现需要被创建的bean

step1: naming an component-scanned bean

@Component("newbeanID")

public subclass implements superinterface{.....}

step2:setting a base package for component scanning

@Configuration

@ComponentScan(basePackage={"a","b","c"})

//@ComponentScan(basePackageClasses={xx.class,xxx.class}

public class classconfig{.....}

##autowiring---自动实现bean注入

@Component
public class CDPlayer implements MediaPlayer{
    private CompactDisc cd;
   
    @Autowired   ( or @Inject)
    public CDPlayer(CompactDisc cd)
    {   
           this.cd =cd;
    }
   
    public void play()
    {
          cd.play();
    }
}

4)混合装载

referencing XML configuration in JavaConfig

referencing JavaConfig in XML configuration