// 如何才能mock掉 WeChatConfigUtil 这个类，让 weChatConfigUtil.getMainApploginSwitch();这个方法返回你想要的结果

public void testA(){

    WeChatConfigUtil weChatConfigUtil = new WeChatConfigUtil();

    weChatConfigUtil.getMainAppLoginSwitch();

  }

package com.ppdai.wechat.sub.business.msgsub;

import com.ppdai.wechat.sub.util.WeChatConfigUtil;

import org.junit.Test;

import org.junit.runner.RunWith;

import org.powermock.api.mockito.PowerMockito;

import org.powermock.core.classloader.annotations.PrepareForTest;

import org.powermock.modules.junit4.PowerMockRunner;

/**

 * Created by huxuhong on 2020/7/2.

 */

//重点，要帮要mock的类（此例为weChatConfigUtil 所在的类TestC，要放到PrepareForTest中即可）

@PrepareForTest(

        {   TestB.TestC.class

        })

@RunWith(PowerMockRunner.class)

public class TestB {

    public TestB(){

    }

    class TestC{

        public void testA(){

            WeChatConfigUtil weChatConfigUtil = new WeChatConfigUtil();

            Boolean flag = weChatConfigUtil.getMainAppLoginSwitch();

            System.out.println("mock结果"+flag);

        }

    }

    @Test

    public void testTestC(){

        TestC testC = new TestC();

        WeChatConfigUtil weChatConfigUtil = PowerMockito.mock(WeChatConfigUtil.class);

        try {

            PowerMockito.whenNew(WeChatConfigUtil.class).withAnyArguments().thenReturn(weChatConfigUtil);

            PowerMockito.doReturn(Boolean.TRUE).when(weChatConfigUtil).getMainAppLoginSwitch();

            testC.testA();

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

}

public class TestB {

    public TestB(){

    }

    class TestC{
       //如何mock掉属性中new 对象（此例为WechatConfigUtil weChatConfigUtil = new WechatConfigUtil,让 weChatConfigUtil.getUserInfoApiUrl 能获取到指定的值）

        WeChatConfigUtil weChatConfigUtil = new WeChatConfigUtil();

        public void testA(){

            String t = weChatConfigUtil.getUserInfoApiUrl();

            System.out.println("mock结果"+t);

        }

    }

public class TestB {

    public TestB(){

    }

    class TestC{
        //如果熟悉修饰为pubilc final static WechatConfigUtil,那么就需要和上面的例子一样要配置@PrepareForTest

        WeChatConfigUtil weChatConfigUtil = new WeChatConfigUtil();

        public void testA(){

            String t = weChatConfigUtil.getUserInfoApiUrl();

            System.out.println("mock结果"+t);

        }

    }

    @Test

    public void testTestC(){

        TestC testC = new TestC();

        WeChatConfigUtil weChatConfigUtil = PowerMockito.mock(WeChatConfigUtil.class);

        try {

            Field weChatConfigUtilField =  testC.getClass().getDeclaredField("weChatConfigUtil");

            weChatConfigUtilField.setAccessible(Boolean.TRUE);

            weChatConfigUtilField.set(testC,weChatConfigUtil);

            PowerMockito.doReturn("testpc").when(weChatConfigUtil).getUserInfoApiUrl();

            testC.testA();

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

}