In the previous chapter, the ECLIPSE,MYBATIS,MYSQL environment has been set up, and a simple query has been implemented. Note that this is done using the sqlsession instance to directly execute the mapped SQL statement:
Session.selectone ("Com.yihaomen.mybatis.models.UserMapper.selectUserByID", 1)
In fact, there are simpler ways, and it's a better way. Using an interface that reasonably describes the parameters and the return value of the SQL statement (for example, Iuseroperation.class), it is now possible to get to that simpler, more secure code, without the error of string literals and conversions that are prone to occur. The following is a detailed procedure:
In the Src_user source directory under the establishment of Com.yihaomen.mybatis.inter this package, and the establishment of interface class Iuseroperation, the contents are as follows:
Program code
Package com.yihaomen.mybatis.inter;
Import Com.yihaomen.mybatis.model.User;
Public interface Iuseroperation {
Public User Selectuserbyid (int id);
}
Note that there is a method name in this Selectuserbyid that must correspond to the ID of the select configured in User.xml (<select id= "Selectuserbyid")
Rewrite test code
Program code
public static void Main (string[] args) {
sqlsession session = Sqlsessionfactory.opensession ();
try {
Iuseroperation Useroperation=session.getmapper (Iuseroperation.class);
User user = Useroperation.selectuserbyid (1);
System.out.println (User.getuseraddress ());
System.out.println (User.getusername ());
} finally {
Session.close ();
}
}
the entire engineering chart is now as follows:
Run the test program and you'll see the results.
MyBatis Learning (2) programming in an interface way
