请求URL中有body怎么使用jmeter进行接口测试

业务场景：

微信内免费领取激活码

1、点击“免费领取”按钮调取的接口

 2、URL如下

https://yxyapi2.drcuiyutao.com/yxy-api-gateway/api/json/vippurchase/getVIPFreeOrder?body=%7B%22openId%22:%22ozW_fvy5gcJDedxMC1mDnVjXIqic%22,%22childCode%22:%22196080795836968960%22,%22proPkgId%22:92,%22sourceType%22:2,%22osType%22:0,%22payType%22:2,%22nickName%22:%22%E5%B0%8F%E7%8E%89%E6%B5%8B%E8%AF%95%E5%BE%AE%E4%BF%A12%22,%22appId%22:%22wxe9655d4fb406e13c%22,%22linkType%22:0%7D

3、使用jemter报错

4、在jmeter添加参数时，勾选编码就OK