查找局域网络中的故障技巧

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.RequiredAnnotationBeanPostProcessorrequired=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"/>