ctrl+n快捷键
（2）idea新建class的时候建不了，以下链接可以解决
https://blog.csdn.net/wang5701071/article/details/80068327
（3）idea在class或方法前面添加注解
https://jingyan.baidu.com/album/19192ad8eb4134e53e5707a6.html?picindex=2
（4）idea安装checkstyle
https://note.youdao.com/ynoteshare1/index.html?id=9e352092ab2e17c7c095b9c46e67bf48&type=note#/
（5）idea安装pmd
https://note.youdao.com/ynoteshare1/index.html?id=13814eb462473fa3fd8dfbd8394405d5&type=note#/