You can use compound or nested property names when you set bean properties, as long as all components of the path except the final property name are not null
. Consider the following bean definition.
你可以使用复合或嵌套属性名称当你设置bean属性时,只要路径中所有组成部分除了最后的属性名外都不为空.考虑下面的bean定义.
<bean id="foo" class="foo.Bar"> <property name="fred.bob.sammy" value="123" /> </bean>
The foo
bean has a fred
property, which has a bob
property, which has a sammy
property, and that final sammy
property is being set to the value 123
. In order for this to work, the fred
property of foo
, and the bob
property of fred
must not be null
after the bean is constructed, or a NullPointerException
is thrown.
foo
bean有一个 fred
属性, fred
有一个 bob
属性, bob
属性有一个 sammy
属性,最后的 sammy
属性的值被设置为 123
.为了让它能够运行,在这个bean被构造后, foo
的 fred
属性, fred
的 bob
属性必须不能为空,不然就会抛出 NullPointerException
.