mybatis xml参数传递详解

List<Student> getStudent(@Param("grade")String grade, @Param("class")String class,@Param("name")String name);

<select id="getStudent" parameterType="java.lang.String" resultType="Student">
        select nn_grade, nn_class, nn_name, nn_age, nn_sex, nn_birthdate, nn_address from student
        <where>
        <if test="grade != null and grade != ‘‘">
            and nn_grade=#{grade}
        </if>
        <if test="class != null and class != ‘‘">
            and nn_class=#{class}
        </if>
        <if test="name != null and name != ‘‘">
            and nn_name=#{name}
        </if>
        </where>
    </select>

List<Student> getStudent(String grade, String class,String name);

<select id="getStudent" parameterType="java.lang.String" resultType="Student">
        select nn_grade, nn_class, nn_name, nn_age, nn_sex, nn_birthdate, nn_address from student
        <where>
        <if test="#{0} != null and #{0} != ‘‘">
            and nn_grade=#{0}
        </if>
        <if test="#{1} != null and #{1} != ‘‘">
            and nn_class=#{1}
        </if>
        <if test="#{2} != null and #{2} != ‘‘">
            and nn_name=#{2}
        </if>
        </where>
    </select>

List<Student> getStudent(Map param);

<select id="getStudent" parameterType="java.util.Map" resultType="Student">
        select nn_grade, nn_class, nn_name, nn_age, nn_sex, nn_birthdate, nn_address from student
        <where>
        <if test="grade != null and grade != ‘‘">
            and nn_grade=#{grade}
        </if>
        <if test="class!=null and class!=‘‘">
            and nn_class=#{class}
        </if>
        <if test="name!=null and name!=‘‘">
            and nn_name=#{name}
        </if>
        </where>
    </select>

List<Student> getStudent(Student stu);

<select id="getStudent" parameterType="Student" resultType="Student">
        select nn_grade, nn_class, nn_name, nn_age, nn_sex, nn_birthdate, nn_address from student
        <where>
        <if test="grade != null and grade != ‘‘">
            and nn_grade=#{grade}
        </if>
        <if test="class!=null and class!=‘‘">
            and nn_class=#{class}
        </if>
        <if test="name!=null and name!=‘‘">
            and nn_name=#{name}
        </if>
        </where>
    </select>

List<Student> getStudentByName(Student stu);

<select id="getStudentByName" parameterType="java.lang.String" resultType="Student">
        select nn_grade, nn_class, nn_name, nn_age, nn_sex, nn_birthdate, nn_address from student
        <where>
        <if test="_parameter!=null and _parameter!=‘‘">
            and nn_name=#{_parameter}
        </if>
        </where>
    </select>

<select id="getStudentByName" parameterType="java.lang.String" resultType="Student">
        select nn_grade, nn_class, nn_name, nn_age, nn_sex, nn_birthdate, nn_address from student
        <where>
        <if test="#{0}!=null and #{0}!=‘‘">
            and nn_name=#{0}
        </if>
        </where>
    </select>