Spring的属性依赖检查
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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
public class Customer { private Person person; private int type; private String action; //getter and setter methods }
public class Person { private String name; private String address; private int age; //getter and setter methods }
1. none dependency checking
[html] view plain copy print?在CODE上查看代码片派生到我的代码片 <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>
2. simple dependency checking
<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>
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
<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>
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
<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>
Global default dependency checking:
default-dependency-check="all"
<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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