Spring中Bean的4种依赖检查模式

在上面的一个例子中，我们看到，通过设立dependency-check="object"属性来在没有找到匹配的情况下抛出错误。这就是类型检查。
下面我们来看看Spring中的Bean的4中依赖检查模式：simple,object,all,none.
1 simple:对基本类型，字符型和集合进行依赖检查。
Java代码

   1. <?xml version="1.0" encoding="UTF-8"?> 
   2. <!DOCTYPE beans Public "-//SPRING//DTD BEAN//EN" 
   3. "http://www.springframework.org/dtd/spring-beans.dtd"> 
   4. <beans> 
   5. <bean id ="HelloWorld" class="com.jnotnull.HelloWorld"  
   6. autowire="autodectect" dependency-check="simple"> 
   7. <bean> 
   8. <bean id="date" class="java.util.Date"> 
   9. </beans> 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans Public "-//SPRING//DTD BEAN//EN"
"http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<bean id ="HelloWorld" class="com.jnotnull.HelloWorld"
autowire="autodectect" dependency-check="simple">
<bean>
<bean id="date" class="java.util.Date">
</beans>


2 object:对依赖的对象进行检查
Java代码

   1. <?xml version="1.0" encoding="UTF-8"?> 
   2. <!DOCTYPE beans Public "-//SPRING//DTD BEAN//EN" 
   3. "http://www.springframework.org/dtd/spring-beans.dtd"> 
   4. <beans> 
   5. <bean id ="HelloWorld" class="com.jnotnull.HelloWorld"  
   6. autowire="autodectect" dependency-check="object"> 
   7. <bean> 
   8. <bean id="date" class="java.util.Date"> 
   9. </beans> 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans Public "-//SPRING//DTD BEAN//EN"
"http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<bean id ="HelloWorld" class="com.jnotnull.HelloWorld"
autowire="autodectect" dependency-check="object">
<bean>
<bean id="date" class="java.util.Date">
</beans>


3 all:对全部属性进行检查
Java代码

   1. <?xml version="1.0" encoding="UTF-8"?> 
   2. <!DOCTYPE beans Public "-//SPRING//DTD BEAN//EN" 
   3. "http://www.springframework.org/dtd/spring-beans.dtd"> 
   4. <beans> 
   5. <bean id ="HelloWorld" class="com.jnotnull.HelloWorld"  
   6. autowire="autodectect" dependency-check="all"> 
   7. <bean> 
   8. <bean id="date" class="java.util.Date"> 
   9. </beans> 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans Public "-//SPRING//DTD BEAN//EN"
"http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<bean id ="HelloWorld" class="com.jnotnull.HelloWorld"
autowire="autodectect" dependency-check="all">
<bean>
<bean id="date" class="java.util.Date">
</beans>


4 none:不进行依赖检查：
Java代码

   1. <?xml version="1.0" encoding="UTF-8"?> 
   2. <!DOCTYPE beans Public "-//SPRING//DTD BEAN//EN" 
   3. "http://www.springframework.org/dtd/spring-beans.dtd"> 
   4. <beans> 
   5. <bean id ="HelloWorld" class="com.jnotnull.HelloWorld"  
   6. autowire="autodectect" dependency-check="none"> 
   7. <bean> 
   8. <bean id="date" class="java.util.Date"> 
   9. </beans> 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans Public "-//SPRING//DTD BEAN//EN"
"http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<bean id ="HelloWorld" class="com.jnotnull.HelloWorld"
autowire="autodectect" dependency-check="none">
<bean>
<bean id="date" class="java.util.Date">
</beans>


由此我们可以看出，依赖检查一般和自动装载进行配套使用。如果没有自动装载，也就没有依赖检查的必要了。