Java 使用具有泛型参数的类定义 spring bean
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Defining spring bean using a class with generic parameters
提问by digiarnie
If I have a class that looks something like this:
如果我有一个看起来像这样的课程：
public class MyClass<T extends Enum<T>> {
public void setFoo(T[] foos) {
....
}
}
How would I go about declaring this as a bean in my context xml so that I can set the Foo array assuming I know what T is going to be (in my example, let's say T is an enum with the values ONE and TWO)?
我将如何在我的上下文 xml 中将它声明为一个 bean，以便我可以设置 Foo 数组，假设我知道 T 将是什么（在我的示例中，假设 T 是一个枚举值 ONE 和 TWO）？
At the moment, having something like this is not enough to tell spring what the type T is:
目前，拥有这样的东西还不足以告诉 spring T 是什么类型：
<bean id="myClass" class="example.MyClass">
<property name="foo">
<list>
<value>ONE</value>
<value>TWO</value>
</list>
</property>
</bean>
Edit: Forgot the list tag.
编辑：忘记了列表标签。
采纳答案by Arne Burmeister
Spring has no generic support for that case, but the compiler just creates a class cast in this case. So the right solution is:
Spring 没有对这种情况的通用支持，但编译器只是在这种情况下创建了一个类。所以正确的解决办法是：
<bean id="myClass" class="example.MyClass">
<property name="foo">
<list value-type="example.MyEnumType">
<value>ONE</value>
<value>TWO</value>
</list>
</property>
</bean>
回答by cletus
<bean id="myClass" class="example.MyClass">
<property name="foo">
<list>
<value>ONE</value>
<value>TWO</value>
</list>
</property>
</bean>
Alternatively, you can define a custom editor.
或者，您可以定义自定义编辑器。
回答by Rod McDonald
Consider working example.
考虑工作示例。
<bean id="simpleInt"
class="org.nipr.gateway.service.transaction_assistant.GenericSimple">
<constructor-arg>
<!-- this can be any full path to a class -->
<value>java.lang.Integer</value>
</constructor-arg>
</bean>
and
和
<bean id="simpleString"
class="org.nipr.gateway.service.transaction_assistant.GenericSimple">
<constructor-arg>
<value>java.lang.String</value>
</constructor-arg>
</bean>
Simple generic class:
简单的泛型类：
public class GenericSimple<T> {
private Class<T> type;
public GenericSimple(Class<T> type) {
this.type = type;
}
public T get( T t) {
return t;
}
}
And finally, the test method (using factory):
最后，测试方法（使用工厂）：
public void testGeneric(){
Factory factory = new Factory(new String[]{"config/beanForGenericTest.xml"});
GenericSimple<Integer> simpleInt
= (GenericSimple<Integer>)factory.getClass("simpleInt");
System.out.println(simpleInt.get(Integer.valueOf(100)));
Assert.assertTrue(simpleInt.get(Integer.valueOf(100)).equals(100));
GenericSimple<String> simpleString =
(GenericSimple<String>)factory.getClass("simpleString");
System.out.println(simpleString.get(new String("Rockets go fast.")));
Assert.assertTrue(simpleString.get("Rockets go fast.")
.equals("Rockets go fast."));
}
