java反射获取方法内部_java 用反射获取内部类构造方法

package com.zl.invoke;

import java.lang.reflect.Constructor;

public class A {

public A() {

}

public A(String str) {

}

class Inner {

private String name = "Inner";

public Inner() {

}

public Inner(String na) {

name = na;

}

}

public static void main(String args[]) {

Object obj = getObject("com.zl.invoke.A");

System.out.println("obj: " + obj.toString());

Object innerObj = getObjectFromInnerClass("com.zl.invoke.A$Inner");

System.out.println("innerObj : " + innerObj.toString());

}

public static Object getObject(String className) {

Object obj = null;

try {

Class c = Class.forName(className);

if (c != null) {

Constructor constructor = c

.getDeclaredConstructor(new Class[] { String.class });

if (constructor != null) {

obj = constructor.newInstance("dlafjdf");

}

}

} catch (Exception e) {

e.printStackTrace();

}

return obj;

}

public static Object getObjectFromInnerClass(String clsName) {

Object obj = null;

try {

Class c = Class.forName(clsName);

if (c != null) {

Constructor constructor = c.getDeclaredConstructor(new Class[] {

A.class, String.class });

if (constructor != null) {

obj = constructor.newInstance(new A(), "dlafjdf");

}

}

} catch (Exception e) {

e.printStackTrace();

}

return obj;

}

}

关键代码用红色字体标注：

获取内部类构造方法时，需要将其外部类的类对象作为参数传进去

Constructor constructor = c.getDeclaredConstructor(new Class[] {

A.class, String.class });

同样实例化内部类时，也需要将外部类对象作为参数传进去

obj = constructor.newInstance(new A(), "dlafjdf");