Mybatis- ordinary sq adds, deletes, modifies and examines study notes

Import java.util.*;import cn.mybatis.entity.Student;import cn.mybatis.util.MybatisUtil;import org.apache.ibatis.session.SqlSession;public class StudentDao {/ * add students * / public void add (Student student) throws Exception {SqlSession sqlSession = null; try {sqlSession = MybatisUtil.getSqlSession () / / transaction start (default) / / read the SQL statement int I = sqlSession.insert (Student.class.getName () + ".add", student) in the StudentMapper.xml mapping file; System.out.println ("this operation affects" + I + "line"); / / transaction commit sqlSession.commit () } catch (Exception e) {e.printStackTrace (); / / transaction rollback sqlSession.rollback (); throw e;} finally {/ / MybatisUtil.closeSqlSession ();}} / * query students according to ID * / public Student findById (int id) throws Exception {SqlSession sqlSession = null Try {sqlSession = MybatisUtil.getSqlSession (); Student student = sqlSession.selectOne (Student.class.getName () + ".findById", id); sqlSession.commit (); return student;} catch (Exception e) {e.printStackTrace (); sqlSession.rollback (); throw e } finally {MybatisUtil.closeSqlSession ();}} / * query all students * / public List findAll () throws Exception {SqlSession sqlSession = null; try {sqlSession = MybatisUtil.getSqlSession (); return sqlSession.selectList (Student.class.getName () + ".findAll") } catch (Exception e) {e.printStackTrace (); throw e;} finally {MybatisUtil.closeSqlSession ();}} / * Update students * / public void update (Student student) throws Exception {SqlSession sqlSession = null; try {sqlSession = MybatisUtil.getSqlSession () SqlSession.update (Student.class.getName () + ".update", student); sqlSession.commit ();} catch (Exception e) {e.printStackTrace (); sqlSession.rollback (); throw e;} finally {MybatisUtil.closeSqlSession () }} / * Delete students * / public void delete (Student student) throws Exception {SqlSession sqlSession = null; try {sqlSession = MybatisUtil.getSqlSession (); sqlSession.delete (Student.class.getName () + ".delete", student); / / transaction sqlSession.commit () } catch (Exception e) {e.printStackTrace (); / / rollback sqlSession.rollback (); throw e;} finally {MybatisUtil.closeSqlSession ();}} public static void main (String [] args) throws Exception {StudentDao dao = new StudentDao () / / dao.add (new Student (3, "Beautiful", 70030.3)); / / dao.add (new Student (4, "come on", 70030.3)); / / dao.add (new Student (5, "relationship", 70030.3)); / / dao.add (new Student (6, "Rule", 70030.3)); / / dao.add (new Student (7, "Gulin", 70030.3)) / / List studentslist = dao.findAll (); / / for (Student student: studentslist) {/ / System.out.print (student.getId () + ":" + student.getName () + ":" + student.getSal ()); / /} / / Student student = dao.findById (4); / / student.setName ("liwen"); / / dao.update (student) }} insert into students (id,name,sal) values (# {id}, # {name}, # {sal}) select id,name,sal from students where id = # {id} select id,name,sal from students update students set name=# {name} Sal=# {sal} where id=# {id} delete from students where id=# {id} select id,name,sal from students limit # {pstart}, # {psize}