public void selectBykeyWord(String keyword) {
   String id = "%" + keyword + "%";
   String roleType = "%" + keyword + "%";
   String roleName = "%" + keyword + "%";
   userDao.selectBykeyWord(id,roleName,roleType);
 }

<select id="selectBykeyWord" parameterType="string" resultType="com.why.mybatis.entity.RoleEntity">
    SELECT
      *
    FROM
      t_role
    WHERE
      role_name LIKE #{roleName}
      OR id LIKE #{id}
      OR role_type LIKE #{roleType}
  </select>

SELECT
  *
FROM
  t_role
WHERE
  role_name LIKE '%why%'
OR id LIKE '%why%'
OR role_type LIKE '%why%';

CONCAT(str1,str2,...)

List<RoleEntity> selectBykeyWord(@Param("keyword") String keyword);

  <select id="selectBykeyWord" parameterType="string" resultType="com.why.mybatis.entity.RoleEntity">
    SELECT
      *
    FROM
      t_role
    WHERE
      role_name LIKE CONCAT('%',#{keyword},'%')
    OR
      id LIKE CONCAT('%',#{keyword},'%')
    OR
      role_type LIKE CONCAT('%',#{keyword},'%')
  </select>

List<RoleEntity> selectBykeyWord(@Param("keyword") String keyword);

<select id="selectBykeyWord" parameterType="string" resultType="com.why.mybatis.entity.RoleEntity">
    <bind name="pattern" value="'%' + keyword + '%'" />
    SELECT
    *
    FROM
    t_role
    WHERE
    role_name LIKE #{pattern}
    OR
    id LIKE #{pattern}
    OR
    role_type like #{pattern}
  </select>