返回list
1、编写接口方法:
public List<Teacher> getTeachersByNameLike(String name); //根据名字模糊查询,返回一个list
2、编写mapper文件
这里的返回值类型是list中元素 的类型,不是List!!!!
<select id="getTeachersByNameLike" resultType="bean.Teacher">
select * from teacher where name like #{name}
</select>
3、编码测试
@Test
public void testSearch4() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
//创建sqlSessionFactory对象
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//生成session实例
try (SqlSession session = sqlSessionFactory.openSession()) {
//获取接口的实现
TeacherMapper teacherMapper = session.getMapper(TeacherMapper.class);
List<Teacher> teachers = teacherMapper.getTeachersByNameLike("%a%");
for(Teacher teacher :teachers) {
System.out.println(teacher);
}
}
}
4、运行结果如下:
返回javabean对象
1、编写接口方法
public Teacher getTeacherByID(Integer id);
2、编写mapper文件
<select id="getTeacherByID" resultType="bean.Teacher">
select * from teacher where id = #{id}
</select>
3、编写测试代码
@Test
public void testSearch() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
//创建sqlSessionFactory对象
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//生成session实例
try (SqlSession session = sqlSessionFactory.openSession()) {
//获取接口的实现
TeacherMapper teacherMapper = session.getMapper(TeacherMapper.class);
Teacher teacher = teacherMapper.getTeacherByID(1);
System.out.println(teacher);
}
}
4、运行结果如下:
返回Map(一条记录)
1、编写接口方法:
public Map<String,Object> getTeacherMapByID(Integer id);
2、编写mapper文件
<select id="getTeacherMapByID" resultType="map">
select * from teacher where id=#{id}
</select>
3、编写测试代码
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@Test
public void testSearch5() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
//创建sqlSessionFactory对象
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//生成session实例
try (SqlSession session = sqlSessionFactory.openSession()) {
//获取接口的实现
TeacherMapper teacherMapper = session.getMapper(TeacherMapper.class);
Map<String,Object> map = teacherMapper.getTeacherMapByID(1);
System.out.println(map);
}
}
4、运行结果
返回Map(多条记录)
1、编写接口方法
@MapKey("name") //封装map的时候使用name作为主键
public Map<String,Object> getTeachesMapByname(String name);
2、编写mapper
<select id="getTeachesMapByname" resultType="bean.Teacher">
select * from teacher where name like #{name}
</select>
3、编写测试代码
@Test
public void testSearch6() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
//创建sqlSessionFactory对象
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//生成session实例
try (SqlSession session = sqlSessionFactory.openSession()) {
//获取接口的实现
TeacherMapper teacherMapper = session.getMapper(TeacherMapper.class);
Map<String,Object> map = teacherMapper.getTeachesMapByname("%a%");
System.out.println(map);
}
}
4、执行结果