如果您找不到优雅的方法，这就是丑陋的方法（Ideone）。涉及反射时通常会发出警告：在将来的发行版中可能会中断
public static void main(String[] args) throws Exception {
Function<String, String> sayHello = name -> "Hello, " + name;
Method m = getmethodFromLambda(sayHello);
registerFunction("World", m);
}
static void registerFunction(String name, Method method) throws Exception {
String result = (String) method.invoke(null, name);
System.out.println("result = " + result);
}
private static Method getmethodFromLambda(Function<String, String> lambda) throws Exception {
Constructor<?> c = Method.class.getDeclaredConstructors()[0];
c.setAccessible(true);
Method m = (Method) c.newInstance(null, null, null, null, null, 0, 0, null, null, null, null);
m.setAccessible(true); //sets override field to true
//m.methodAccessor = new LambdaAccessor(...)
Field ma = Method.class.getDeclaredField("methodAccessor");
ma.setAccessible(true);
ma.set(m, new LambdaAccessor(array -> lambda.apply((String) array[0])));
return m;
}
static class LambdaAccessor implements MethodAccessor {
private final Function<Object[], Object> lambda;
public LambdaAccessor(Function<Object[], Object> lambda) {
this.lambda = lambda;
}
@Override public Object invoke(Object o, Object[] os) {
return lambda.apply(os);
}
}
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