Spring支持4种依赖检查：默认的是none
- none – No dependency checking.
- simple – If any properties of primitive type (int, long,double…) and collection types (map, list..) have not been set, UnsatisfiedDependencyException will be thrown.
- objects – If any properties of object type have not been set, UnsatisfiedDependencyException will be thrown.
all – If any properties of any type have not been set, an UnsatisfiedDependencyException will be thrown.
举个例子：
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public class Customer{ private Person person;
private int type;
private String action;
//getter and setter methods
} |
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public class Person{ private String name;
private String address;
private int age;
//getter and setter methods
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1. none dependency checking
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<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<bean id="CustomerBean" class="com.mkyong.common.Customer" >
<property name="action" value="buy" />
</bean>
<bean id="PersonBean" class="com.mkyong.common.Person">
<property name="name" value="mkyong" />
<property name="address" value="address ABC" />
<property name="age" value="29" />
</bean>
</beans>
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2. simple dependency checking
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<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<bean id="CustomerBean" class="com.mkyong.common.Customer"
dependency-check="simple">
<property name="person" ref="PersonBean" />
<property name="action" value="buy" />
</bean>
<bean id="PersonBean" class="com.mkyong.common.Person">
<property name="name" value="mkyong" />
<property name="address" value="address ABC" />
<property name="age" value="29" />
</bean>
</beans>
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注意此处type字段故意没有设置，这样会出现UnsatisfiedDependencyException
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'CustomerBean' defined in class path resource [config/Spring-Customer.xml]: Unsatisfied dependency expressed through bean property 'type': Set this property value or disable dependency checking for this bean.
3. objects dependency checking
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<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<bean id="CustomerBean" class="com.mkyong.common.Customer"
dependency-check="objects">
<property name="action" value="buy" />
<property name="type" value="1" />
</bean>
<bean id="PersonBean" class="com.mkyong.common.Person">
<property name="name" value="mkyong" />
<property name="address" value="address ABC" />
<property name="age" value="29" />
</bean>
</beans>
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此处故意没有设置”person“属性，会出现UnsatisfiedDependencyException
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'CustomerBean' defined in class path resource [config/Spring-Customer.xml]: Unsatisfied dependency expressed through bean property 'person': Set this property value or disable dependency checking for this bean.
4. all dependency checking
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<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<bean id="CustomerBean" class="com.mkyong.common.Customer"
dependency-check="all">
<property name="action" value="buy" />
</bean>
<bean id="PersonBean" class="com.mkyong.common.Person">
<property name="name" value="mkyong" />
<property name="address" value="address ABC" />
<property name="age" value="29" />
</bean>
</beans>
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Global default dependency checking：
default-dependency-check="all"
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<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"
default-dependency-check="all">
<bean id="CustomerBean" class="com.mkyong.common.Customer">
<property name="action" value="buy" />
<property name="type" value="1" />
</bean>
<bean id="PersonBean" class="com.mkyong.common.Person">
<property name="name" value="mkyong" />
<property name="address" value="address ABC" />
<property name="age" value="29" />
</bean>
</beans>
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==============================================================================
本文转自被遗忘的博客园博客，原文链接：http://www.cnblogs.com/rollenholt/archive/2012/12/27/2835270.html，如需转载请自行联系原作者