param.setUsername("%CD%");
param.setPassword("%11%");spa
<select id="selectPersons" resultType="person" parameterType="person"> select id,sex,age,username,password from person where true <if test="username!=null"> AND username LIKE #{username}</if> <if test="password!=null">AND password LIKE #{password}</if> </select>
<select id="selectPersons" resultType="person" parameterType="person"> <bind name="pattern" value="'%' + _parameter.username + '%'" /> select id,sex,age,username,password from person where username LIKE #{pattern} </select>
where username LIKE concat(concat('%',#{username}),'%')