[英]Java, return method as reference
Im beginner JAVA developer. 我是初学者JAVA开发者。 Here is a method: 这是一个方法:
private Method getSomething()
{
for (Method m : getClass().getDeclaredMethods())
{
return m;
}
return notFound;
}
private void notFound()
{
throw new Exception();
}
it doesnt matter what it does - if it finds something, then returns a Method
- if not, the notFound()
method itself should be returned. 它无关紧要 - 如果它找到了什么,然后返回一个Method
- 如果没有,则应该返回notFound()
方法本身。 So the hot spot is at the return notFound;
因此,热点在return notFound;
line: if I use return notFound();
line:如果我使用return notFound();
then it returns its value, not the method itself. 然后它返回它的值,而不是方法本身。 I want something like a reference/pointer. 我想要像引用/指针这样的东西。 So getSomething()
returns something what can be called, and if the returned method is used wrong, it should trigger that Exception - so its not an option to replace return notFound;
所以getSomething()
返回可以调用的东西,如果返回的方法使用错误,它应该触发异常 - 所以它不是替换return notFound;
的选项return notFound;
with throw new Exception();
with throw new Exception();
! ! Or the 2nd option is to create a lambda method.... 或者第二个选项是创建一个lambda方法....
You need to call 你需要打电话
this.getClass().getMethod("notFound")
to get the notFound
method of the current/this object's class. 获取当前/此对象类的notFound
方法。
So just do this: 所以这样做:
return this.getClass().getMethod("notFound");
More details here: 更多细节在这里:
Class.getMethod Class.getMethod
EDIT: 编辑:
You can retrieve ie get and call private methods too via reflection. 您可以通过反射检索即获取和调用私有方法。
Here is an example. 这是一个例子。
import java.lang.reflect.Method;
public class Test001 {
public static void main(String[] args) throws Exception {
Test002 obj = new Test002();
Method m = obj.getClass().getDeclaredMethod("testMethod", int.class);
m.setAccessible(true);
m.invoke(obj, 10);
m.invoke(obj, 20);
System.out.println(m.getName());
}
}
class Test002 {
private void testMethod(int x){
System.out.println("Hello there: " + x);
}
}
You need to use reflection to achieve this: 您需要使用反射来实现此目的:
http://docs.oracle.com/javase/tutorial/reflect/ http://docs.oracle.com/javase/tutorial/reflect/
eg to get all methods of a given class: 例如,获取给定类的所有方法:
Class aClass = ...//obtain class object
Method[] methods = aClass.getMethods();
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