Spring的属性依赖检查-优快云博客

本文详细解释了Spring框架中四种依赖检查配置：none、simple、objects和all，通过实例展示了如何在XML配置文件中应用这些配置，并解析了它们在不同场景下的行为。重点在于理解依赖检查如何影响Spring容器的行为，以及如何正确配置以避免或处理未满足的依赖。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

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

<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>

转载于:https://www.cnblogs.com/rollenholt/archive/2012/12/27/2835270.html