Name、SuperClass、Constructor、Field、Method

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Name

SuperClass

Constructor

Field

Method

获取

getName

getSimpleName

getSuperClass

getConstructor

getDeclaredConstructor+setAccessible

getConstructors

getField

getDeclaredFields+setAccessible

getFields

使用

(Class) newInstance

set

set*

get

get*

invoke

getX和getXs都只能获取public的构造函数、成员变量、成员函数。

如果需要使用protected/private的，需要使用getDeclaredX+setAccessible()禁用安全检查。

此外，对于静态元素，使用的时候第一个参数object传null即可。

Java Code

package com.bjsxt.test;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import com.bjsxt.test.bean.User;

public class Test {

    public static void main(String[] args) {

        String path="com.bjsxt.test.bean.User";

        try {
            Class<?> clazz = Class.forName(path);
            System.out.println(clazz.getName());
            System.out.println(clazz.getSimpleName());
            clazz.getSuperclass();

            //获取所有public的构造函数
            Constructor<?>[] constructors = clazz.getConstructors();
            for (Constructor<?> constructor2 : constructors) {
                System.out.println(constructor2);
            }

            Constructor<?> constructor = clazz.getDeclaredConstructor(int.class, int.class, String.class );
            User user=(User)constructor.newInstance(1, 18, "shadowfaxghh");
            System.out.println(user.getUname());

            //也可以直接使用class.newInstance()，此时会调用默认的无参构造方法，因为此时为private，故会报java.lang.IllegalAccessException
//          User user2=(User)clazz.newInstance();

            Field declaredField = clazz.getDeclaredField("uname");
            declaredField.setAccessible(true);
            declaredField.set(user, "abcde");
            System.out.println(declaredField.get(user));

            Method declaredMethod = clazz.getDeclaredMethod("setUname", String.class);
            declaredMethod.invoke(user, "xxx");
            declaredMethod.setAccessible(true);
            System.out.println(user.getUname());

        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (SecurityException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        } catch (NoSuchFieldException e) {
            e.printStackTrace();
        }
    }

}

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