How to get parameter names with Java reflection [duplicate]
-
21-04-2021 - |
Frage
How do I get method signatures with Java reflection?
EDIT: I actually need the parameter NAMES not the types of a method.
Lösung
To get the method i of a class C you call C.class.getMethods()[i].toString()
.
EDIT: Obtaining parameter names is not possible using the reflection API.
But wen you compiled your class with debug information, it is possible to extract the information from bytecode. Spring does it using the ASM bytecode engineering library.
See this answer for further information.
Andere Tipps
http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/reflect/Method.html#toString()
use the toString()
method of java.lang.reflect.Method
object for the method you are looking for.
If you want to know how to get that method object just use this as a reference:
Method toString = class.forName("java.lang.String").getDeclaredMethod("toString");
System.out.println(toString);
import java.lang.reflect.Method;
public class method1 {
private int f1(Object p, int x) throws NullPointerException
{
if (p == null)
throw new NullPointerException();
return x;
}
public static void main(String args[])
{
try {
Class cls = Class.forName("method1");
Method methlist[] = cls.getDeclaredMethods();
for (int i = 0; i < methlist.length; i++) {
Method m = methlist[i];
System.out.println("name = " + m.getName());
System.out.println("decl class = " + m.getDeclaringClass());
Class pvec[] = m.getParameterTypes();
for (int j = 0; j < pvec.length; j++)
System.out.println("param #" + j + " " + pvec[j]);
Class evec[] = m.getExceptionTypes();
for (int j = 0; j < evec.length; j++)
System.out.println("exc #" + j + " " + evec[j]);
System.out.println("return type = " + m.getReturnType());
System.out.println("-----");
}
}
catch (Throwable e) {
System.err.println(e);
}
}
}