Spring2.5学习笔记1-控制反转-Autowiring策略(续)

三、@Autowired注解

     @Autowired注解作用与属性 方法和构造器，启用此注解需要定义org.springframework.beans.factory.annotation.RequiredAnnotationBeanPostProcessor

required=false 可以使的@ Autowired注解的属性方法在找不到协作者时不报错
 小结：@Required注解针对dependency-check属性提出，@Autowired针对autowire属性提出,@Autowired的required 可以进行@Required的依赖检查工作
 四 、 细粒度Autowiring策略控制
          primary属性虽然可以避免多个协作者的异常，但是不能满足企业级应用需求，比如多个同类型不同协作者注入到它能够以受管bean的时候。@Qualifier注解可以解决此类问题。

package cn.beanfactory.bean;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;

public class QualifierBean {
  @Autowired
  @Qualifier("h1")//默认注解
  @FineQualifier(keyFine="k1",valueFine="v1")//自定义注解
    private HelloWorld hw1;
  @Autowired
  @Qualifier("h2")//默认注解
  @FineQualifier(keyFine="k2",valueFine="v2")//自定义注解
    private HelloWorld hw2;
  public HelloWorld getHw2() {
    return hw2;
  }
  public void setHw2(@FineQualifier(keyFine="k2",valueFine="v2") HelloWorld hw2) {
    this.hw2 = hw2;
  }
  public HelloWorld getHw1() {
    return hw1;
  }
  public void setHw1(@FineQualifier(keyFine="k1",valueFine="v1") HelloWorld hw1) {
    this.hw1 = hw1;
  }

}

package cn.beanfactory.bean;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import org.springframework.beans.factory.annotation.Qualifier;

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD,ElementType.PARAMETER})
@Qualifier //无此注释时     需要借助 org.springframework.beans.factory.annotation.CustomAutowireConfigurer对象
public @interface FineQualifier {
    String keyFine() default "";
    String valueFine() default "";

}

<!-- @Qualifier 注解 -->
    <bean name="qualifierBean" class="cn.beanfactory.bean.QualifierBean"        autowire="byType">
    
    </bean>
    <bean name="hw1" class="cn.beanfactory.bean.HelloWorld" >
    <!-- 自定义限定注解 -->
    <qualifier type="cn.beanfactory.bean.FineQualifier">
        <attribute key="keyFine" value="k1"/>
        <attribute key="valueFine" value="v1"/>
    </qualifier>
    <!--        <qualifier value="h1"/> -->
    </bean>
    <bean name="hw2" class="cn.beanfactory.bean.HelloWorld">
    <!-- 自定义限定注解 -->
    <qualifier type="cn.beanfactory.bean.FineQualifier">
        <attribute key="keyFine" value="k2"/>
        <attribute key="valueFine" value="v3"/>
    </qualifier>
    <!-- <qualifier value="h2"/> -->
    </bean>
  <!-- FineQualifier 无类一级的@Qualifier时需要借助以下对象 -->
  
  <bean id="customAutowireConfiger"
    class="org.springframework.beans.factory.annotation.CustomAutowireConfigurer">
    <property name="customQualifierTypes">
      <set>
        <value>cn.beanfactory.bean.FineQualifier</value>
      </set>
    </property>
  </bean>

      注：<context:annotation-config /> 元素可以提供各种注解的支持对象例如：RequiredAnnotationBeanPostProcessor，但是却不能自定义RequiredAnnotationBeanPostProcessor行为

五、depends-on 属性
ref属性虽然能完成依赖注入，但是不能保证按照开发者指定的循序实例化，depends-on 属性可以强制指定依赖对象，从而优先实例化依赖对象。
      

<!-- @Qualifier 注解 -->
  <bean name="qualifierBean" class="cn.beanfactory.bean.QualifierBean" depends-on="hw1,hw2"
    autowire="byType">

  </bean>
  <bean name="hw1" class="cn.beanfactory.bean.HelloWorld">
    <!-- 自定义限定注解 -->
    <qualifier type="cn.beanfactory.bean.FineQualifier">
      <attribute key="keyFine" value="k1" />
      <attribute key="valueFine" value="v1" />
    </qualifier>
    <!-- <qualifier value="h1"/> -->
  </bean>
  <bean name="hw2" class="cn.beanfactory.bean.HelloWorld">
    <!-- 自定义限定注解 -->
    <qualifier type="cn.beanfactory.bean.FineQualifier">
      <attribute key="keyFine" value="k2" />
      <attribute key="valueFine" value="v2" />
    </qualifier>
    <!-- <qualifier value="h2"/> -->
  </bean>

六、抽象Bean和子Bean

package cn.beanfactory.bean;

public class AbstractBean {
  private String username;
  private String password;
  public String getUsername() {
    return username;
  }
  public void setUsername(String username) {
    this.username = username;
  }
  public String getPassword() {
    return password;
  }
  public void setPassword(String password) {
    this.password = password;
  }
  
  

}

  log.info("==========抽象类和子Bean==========");

    AbstractBean abstractBean = gbfa.getBean("childBean1");
    log.info("userName=" + abstractBean.getUsername());
    log.info("password=" + abstractBean.getPassword());

    AbstractBean abstractBean2 = gbfa.getBean("childBean2");
    log.info("userName=" + abstractBean2.getUsername());
    log.info("password=" + abstractBean2.getPassword());
    AbstractBean abstractBean3 = gbfa.getBean("childBean3");
    log.info("userName=" + abstractBean3.getUsername());
    log.info("password=" + abstractBean3.getPassword());

  <!-- 抽象和子Bean -->
  <!-- 抽象Bean Spring 不会实例化 -->
  <bean id="abstractBean1"    class="cn.beanfactory.bean.AbstractBean" abstract="true">
    <property name="username" value="un_ab1"/>
  </bean>
  <bean id="childBean1" class="cn.beanfactory.bean.AbstractBean" parent="abstractBean1">
    <property name="password" value="pwd_cb1"/>
  </bean>
  
  <bean id="abstractBean2" abstract="true">
    <property name="username"    value="un_ab2"/>
  </bean>
  <bean id="childBean2" class="cn.beanfactory.bean.AbstractBean" parent="abstractBean2"    >
    <property name="password" value="pwd_cb2"/>
  </bean>
    <!-- 继承    -->
  <bean id="childBean3" class="cn.beanfactory.bean.AbstractBean" parent="childBean2">
    <property name="username" value="un_cb3"/>    <!-- 覆盖父Bean属性值   -->
  </bean>

七、别名 alias
<alias name="testBean" alias="tb"/>