在實際工作中，有時候需要動態獲取某個類的方法引數名，一般反射機制是獲取不到的，需要藉助位元組碼工具才可以獲取到。

package com.yanek.soa.test;

import java.lang.reflect.Modifier;

import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtMethod;
import javassist.bytecode.CodeAttribute;
import javassist.bytecode.LocalVariableAttribute;
import javassist.bytecode.MethodInfo;

public class MethodVariableNameUtil {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
	
		String[] names=getMethodVariableName("com.yanek.soa.test.Test","test2");
		for(String name:names)
		{
			System.out.println(name);
		}

	}
	

	/**
	 * 獲取方法的引數變數名稱
	 * @param classname
	 * @param methodname
	 * @return
	 */
	public static String[] getMethodVariableName(String classname,String methodname){
		 try{
			 ClassPool pool = ClassPool.getDefault();  
	         CtClass cc = pool.get(classname);  
	         CtMethod cm = cc.getDeclaredMethod(methodname);
	         MethodInfo methodInfo = cm.getMethodInfo();
             CodeAttribute codeAttribute = methodInfo.getCodeAttribute();
             String[] paramNames = new String[cm.getParameterTypes().length];
             LocalVariableAttribute attr = (LocalVariableAttribute) codeAttribute.getAttribute(LocalVariableAttribute.tag);  
             if (attr != null)  {
                 int pos = Modifier.isStatic(cm.getModifiers()) ? 0 : 1;  
                 for (int i = 0; i < paramNames.length; i++){
                	 paramNames[i] = attr.variableName(i + pos); 
                 }
                 return paramNames;
             }
		 }catch(Exception e){
			 System.out.println("getMethodVariableName fail "+e);
		 }
		 return null;
	}

	

}
 

package com.yanek.soa.test;

public class Test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
	

	}
	
	
    public  String test(String a,String b,User user) {
        return "hello";
    }
    
    public static String test2(String a,String b,User user) {
        return "hello";
    }

    public static String test3(String p1,String p2,User user) {
        return "hello";
    }
    
    
}
 

      執行 則可以獲取到方法列表。相關maven依賴：

		<dependency>
			<groupId>javassist</groupId>
			<artifactId>javassist</artifactId>
			<version>3.12.1.GA</version>
		</dependency>