The things that I learned today

When you write a reference structure in a class, it is best to write its parameterless structure, because it has a hidden parameterless construct by default, but when you write a reference structure, its parameterless structure is captured, and the wood has it. So you have to write it manually.

When writing SQL query statements in Java, be sure to bring the conditions, where a certain =?

The URL of the linked database, be sure to remember to change its library name

In a method, if the type is void, the wood has a return value, and the Int,boolean is returned according to its type.

Struts2 must inherit the Actionsupport.

And when using STRUTS2, the Web configuration should be written

<filter-class>
Org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter
</filter-class>

Because it is said that this is going to start the interceptor (although I didn't use it)

All right, here's the end of the summary today!

Not eating is hungry ...

The things that I learned today