Stage 3 1.Mybatis_09.Mybatis multi-table operation _9 mybatis many-operation - to query the user to obtain information about the user roles included

sql statement to the user as a master table

of all information users, that role under the user. Not all users have a role, there is the role of took the role. It is not the role is null

First modify entity classes

Define List <Role> generate getter and setter