有另一种方法来完成语句映射。 它们映射的语句可以不用 XML 来配置，而可以使用 Java 注解来配置。
使用注解来映射简单语句会使代码显得更加简洁，但对于稍微复杂一点的语句，Java 注解不仅力不从心，还会让你本就复杂的 SQL 语句更加混乱不堪。
如果你需要做一些很复杂的操作，最好用 XML 来映射语句。
需要在config.xml中注册Java接口
<mappers> <mapper class="com.mybatis.DAO.PeopleMapper"/> </mappers>
要用class=
public interface PeopleMapper {
@Select("select * from people")
List<People> getPeopleList();
}
增
可以先开启事务自动提交
public static SqlSession getSqlSession(){
return sqlSessionFactory.openSession(true);
}
}
Mapper.java
public interface PeopleMapper {
@Select("select * from people")
List<People> getPeopleList();
@Insert("insert into people(id, name, age, address) VALUES (#{id},#{name},#{age},#{address})")
int addPeople(People people);
}
test
public class PeopleDAOtest {
@Test
public void print() {
SqlSession sqlSession = MybatisUtils.getSqlSession();
PeopleMapper peopleMapper = sqlSession.getMapper(PeopleMapper.class);
List<People> people = peopleMapper.getPeopleList();
for (People p :people){
System.out.println(p);
}
sqlSession.close();
}
@Test
public void add(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
PeopleMapper peopleMapper = sqlSession.getMapper(PeopleMapper.class);
peopleMapper.addPeople(new People(6,"圣迭戈",456,"啥地方"));
print();
}
}
因为已经自动提交了，所以不需要sqlSession.commit();
注解@Param
只能用于基本数据类型
传入的参数只能和sql语句中参数一样
多个参数
样例
public interface PeopleMapper {
@Delete("delete people from people where id=#{uid}")
int delPeople(@Param("uid") int i);
}
test
public class PeopleDAOtest {
@Test
public void del(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
PeopleMapper peopleMapper = sqlSession.getMapper(PeopleMapper.class);
peopleMapper.delPeople(6);
print();
}
}
Mapper.java
public interface PeopleMapper {
@Update("update mybatis.people set name=#{name} ,age=#{age} ,address=#{address} where id=#{id}")
int updateP(People people);
}
test
public class PeopleDAOtest {
@Test
public void update(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
PeopleMapper peopleMapper = sqlSession.getMapper(PeopleMapper.class);
peopleMapper.updateP(new People(5,"圣迭戈",456,"啥地方"));
print();
}
}
