springboot提交表单提示NullPointerException

This application has no explicit mapping for /error, so you are seeing this as a fallback.

Wed Apr 24 12:54:08 CST 2019
There was an unexpected error (type=Internal Server Error, status=500).
No message available
java.lang.NullPointerException
    at com.apitest.service.impl.ApplicationTableServiceImpl.insert(ApplicationTableServiceImpl.java:51)
    at com.apitest.controler.AddDeleteAndChangeControler.ProjectinfoTemp(AddDeleteAndChangeControler.java:59)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)

修改写法：

程序运行正常