StudentMapper.java
StudentMapper.xml
1. 传入多个String类型参数, 使用@Param注解
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>
2. 传入多个String类型参数, 使用#{0},#{1},#{2}……
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>
3. 传入多个String类型参数, 使用Map
grade,class,name是Map的key
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>
4. 传入多个String类型参数, 使用对象Student
grade,class,name是Student对象的属性
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>
5. 传入单个基本类型和String类型等参数, 使用_parameter或#{0}
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>
6. 传入单个基本类型和String类型等参数, 使用_parameter或#{0}