java获取方法的参数名-优快云博客

本文介绍了一个使用Java反射和javassist库来获取类的方法信息并打印其参数名称的工具类实现。通过ClassInformationUtil类的printMethodInfo方法，可以详细展示指定类的所有声明方法及其局部变量属性。

reflect.ClassInformationUtil.java

package reflect;

import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtMethod;
import javassist.Modifier;
import javassist.bytecode.CodeAttribute;
import javassist.bytecode.LocalVariableAttribute;
import javassist.bytecode.MethodInfo;
import velocity.VelocityUtil;

public class ClassInformationUtil {

    public static void printMethodInfo(Class<?> clazz) {
        try {
            ClassPool pool = ClassPool.getDefault();
            CtClass cc = pool.get(clazz.getName());
            CtMethod[] cms = cc.getDeclaredMethods();

            for (CtMethod cm : cms) {
                System.out.println("--------------------");
                System.out.println("method name is :"+cm.getName());
                MethodInfo methodInfo = cm.getMethodInfo();
                CodeAttribute codeAttribute = methodInfo.getCodeAttribute();
                LocalVariableAttribute attr = (LocalVariableAttribute) codeAttribute.getAttribute(LocalVariableAttribute.tag);
                if (attr == null) {
                    System.err.println("attr is null");
                    continue;
                }
                int pos = Modifier.isStatic(cm.getModifiers()) ? 0 : 1;
                for (int i = 0; i < cm.getParameterTypes().length; i++) {
                    String parameterName = attr.variableName(i+pos);
                    System.out.print(parameterName+" ");
                }
                System.out.println();
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>Document</groupId>
    <artifactId>Document</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.javassist</groupId>
            <artifactId>javassist</artifactId>
            <version>3.15.0-GA</version>
        </dependency>
    </dependencies>
</project>