如何使用工厂方法返回创建类型为string bean的arraylist

Question

I have a method in a class that returns a ArrayList, and I want to use this return to create a bean like this:

<bean id="myList" factory-bean="myClass" factory-method="getMyList" class="java.util.ArrayList">
    <constructor-arg index="0" type="java.lang.String">
        <util:constant static-field="com.myapp.searchapp.MY_VALUE"/>
    </constructor-arg>
</bean>

But when I try to ref this bean from another bean IntelliJ complains that:

Bean must be one of these types: java.lang.String or java.util.ArrayList<java.lang.String> less... (Ctrl+F1) 
Checks value types for Spring injections (properties & constructor arguments)

What exactly am I doing wrong here?

Answer 1

..as mentioned in comment, you must ensure the "factory-method" takes no arguments:

package foo.bar;
...
public class MyClass {
  ...
  public List<String> getMyList() {
    //maybe rather a copy than the original ;)
    return daList;
  }
...

Given eg a 1-String constuctor:

...
  public MyClass(String one) {
    daList = new ArrayList<>();
    daList.add(one); 
  }
...
}

...and a the constant String com.myapp.searchapp.MY_VALUE you could wire it all like:

<bean id="myClass" class="foo.bar.MyClass">
  <constructor-arg index="0" type="java.lang.String">
      <util:constant static-field="com.myapp.searchapp.MY_VALUE" />
  </constructor-arg>
</bean>

<!-- and... -->
<bean id="myList" factory-bean="myClass" factory-method="getMyList" />

Here - the top googl-hit on "spring factory method"

... here - a popular, related & maybe helpful question.