SSH framework grouping Query

SSH framework grouping Query

Today, when I was working on an SSH framework project, I encountered a group query problem. The details are as follows:

The two items need to appear. The first thought was to List the content on the left and check the numbers on the right according to the content on the left, but this requires two different databases, very Uncomfortable. Later I thought about grouping queries and checked the materials to implement this function,

Write the following method:

First, you must create a virtual JavaBean with the following content:

The set/get method of the corresponding attribute is provided in the JavaBean, and the construction method with and without parameters is also required.

You can find the List set of this JavaBean in Action, as shown below:

 

The following describes how to implement the dao layer:

 

For the HQL query, remember that the HQL query statement requires the new and package names. However, if @ SuppressWarnings ("unchecked") is not added, a yellow warning always appears. What is the problem? Do you know anything?