MyBatis passing parameters to Mapping.xml

The first scenario, passed by ordinal

The function method of DAO layer

Public User Selectuser (String name,string area);

The corresponding Mapper.xml

<select id= "Selectuser" resultmap= "Baseresultmap" >    Select  * from  user_user_t   where user_name = #{0} and user_area=#{1}</select>

Where #{0} represents the first parameter in the DAO layer, #{1} represents the second parameter in the DAO layer, and more parameters are consistently added.

The second scenario, passing through map

This method uses map to pass multiple parameters.

The function method of DAO layer

Public User Selectuser (Map parammap);

The corresponding Mapper.xml

<select id= "Selectuser" resultmap= "Baseresultmap" >   Select  * from  user_user_t   where user_name = #{username,jdbctype=varchar} and user_area=#{userarea,jdbctype=varchar}</select>

Service Layer Invocation

Private User Xxxselectuser () {Map parammap=new hashMap ();p arammap.put ("UserName", "corresponding to specific parameter values");p arammap.put ("Userarea "," corresponding to the specific parameter value "); User user=xxx. Selectuser (PARAMMAP);}

Personally, this method is not intuitive enough to see the interface method can not directly know what parameters to pass.

The third scenario, passed by a single parameter name with @param, is recommended

The function method of DAO layer

Public User Selectuser (@param ("UserName") Stringname, @param ("Userarea") of String area);

The corresponding Mapper.xml

<select id= "Selectuser" resultmap= "Baseresultmap" >   Select  * from  user_user_t   where user_name = #{username,jdbctype=varchar} and user_area=#{userarea,jdbctype=varchar}</select>

The fourth scheme, passed through the parameter object with @param

The function method of DAO layer

Public User Selectuser (@param ("user") user user, @param ("Userarea") of String area);

The corresponding Mapper.xml

<select id= "Selectuser" resultmap= "Baseresultmap" >   Select  * from  user_user_t   where user_name = #{user.username, Jdbctype=varchar} and User_area=#{userarea,jdbctype=varchar} </select>

In each of these ways, you do not need to write the ParameterType property in XML

MyBatis passing parameters to Mapping.xml