java - 是否可以静态地反射(reflect)一个java方法？

Question

有没有办法在 Java 中静态引用反射方法。下面是一些示例代码，可让您了解我正在尝试的内容:

public void myFunc(int x) { ... }

public void other() {
    Method m1 = getClass().getMethod("myFunc");  // dynamic
    Method m2 = this.myFunc;                     // static
    Method m3 = MyClass.myFunc;                  // static (alternate)
}

我知道上面的语法不起作用，但我想知道是否有某种类似于此的语法确实有效。我想要一种使用反射的方法，而不必担心通过字符串引用方法的固有危险。

有没有办法做到这一点，还是白日做梦？

Answer 1

Method references解释

this method to compare the birth dates of two Person instances already exists as Person.compareByAge. You can invoke this method instead in the body of the lambda expression:

Arrays.sort(rosterAsArray,
    (a, b) -> Person.compareByAge(a, b)
);

Because this lambda expression invokes an existing method, you can use a > method reference instead of a lambda expression:

Arrays.sort(rosterAsArray, Person::compareByAge);

它继续解释各种方法引用:

There are four kinds of method references:

Reference to a static method      ContainingClass::staticMethodName

Reference to an instance method
of a particular object            containingObject::instanceMethodName

Reference to an instance method   ContainingType::methodName
of an arbitrary object of a
particular type

Reference to a constructor        ClassName::new

---

历史记录(写于 Java 8 定稿之前)

我认为 Java 闭包提案有类似的内容。 Stephen Colebourne说:

Stefan and I are pleased to announce the release of v0.4 of the First-class Methods: Java-style closures proposal.

Changes

Since v0.3, we have tried to incorporate some of the feedback received on the various forums. The main changes are as follows:

1) Constructor and Field literals. It is now possible to create type-safe, compile-time changed instances of java.lang.reflect.Constructor and Field using FCM syntax:

// method literal:
Method m = Integer#valueOf(int);

// constructor literal:
Constructor<Integer> c = Integer#(int);

// field literal:
Field f = Integer#MAX_VALUE;

但我不认为这种语法在任何发布的 JVM 中可用。闭包本身绝对不在 Java 7 中。您可能会在 Java 8 中看到它。

Java closures site有指向 "Method references" 的指针虽然看起来他们对语法的更改并不多，但它有点更新。