java 如何使用反射调用带参数的方法？
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How do I use reflection to invoke a method with parameters?
提问by kasavbere
Here is my class:
这是我的课：
public class A{
private void doIt(int[] X, int[] Y){
//change the values in X and Y
}
}
I have another class that is trying to use doItto modify two arrays. I have an error in my code but can't find it.
我有另一个类试图doIt用来修改两个数组。我的代码中有错误，但找不到。
public class B{
public void myStuff(){
A myA = new A();
int[] X = {1,2,3,4,5};
int[] Y = {4,5,6,7,8,9};
Method doIt = A.class.getDeclaredMethod("doIt",new Object[]{X,Y}); // error
doIt.setAccessible(true);
doIt.invoke(myA,new Object[]{X,Y});
}
}
Any help on how to fix method myStuff?
有关如何修复方法的任何帮助myStuff？
If I use getDeclaredMethod("doIt",new Object[]{X,Y});the code does not compile.
如果我使用getDeclaredMethod("doIt",new Object[]{X,Y});的代码不编译。
If instead I have getDeclaredMethod("doIt",null);then it says NoSuchMethodException.
如果相反，我有getDeclaredMethod("doIt",null);那么它说NoSuchMethodException。
回答by Pshemo
Your method is declared with two int arrays
您的方法是用两个 int 数组声明的
private void doIt(int[] X, int[] Y)
and if you wan to find that method you also need to put its argument types to prevent finding other method with same name but different types.
如果您想找到该方法，您还需要放置其参数类型，以防止找到具有相同名称但类型不同的其他方法。
A.class.getDeclaredMethod("doIt", int[].class, int[].class)
回答by Matt Ball
The doItmethod takes twoparameters. Consequently you need to pass twoparameters, in addition to the method name, to Class#getDeclaredMethod(). The two additional parameters need to be instances of Class, which an Object[]is obviously not.Specifically, those Classinstances need to be the same as the types of the parameters that doItaccepts.
该doIt方法有两个参数。因此，除了方法名称之外，您还需要将两个参数传递给Class#getDeclaredMethod(). 这两个附加参数需要是 的实例Class，而 anObject[]显然不是。具体来说，这些Class实例需要与doIt接受的参数类型相同。
Method doIt = A.class.getDeclaredMethod("doIt", int[].class, int[].class);
回答by Edwin Dalorzo
Shouldn't it be?
不应该吗？
Method doIt = A.class.getDeclaredMethod("doIt", int[].class, int[].class);
