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mybatis-普通sq增删改查学习笔记

发表于：2024-11-18 作者：千家信息网编辑

千家信息网最后更新 2024年11月18日，import java.util.*;import cn.mybatis.entity.Student;import cn.mybatis.util.MybatisUtil;import org.ap

千家信息网最后更新 2024年11月18日mybatis-普通sq增删改查学习笔记

import java.util.*;import cn.mybatis.entity.Student;import cn.mybatis.util.MybatisUtil;import org.apache.ibatis.session.SqlSession;public class StudentDao {    /**     * 增加学生     */    public   void add(Student student) throws Exception{        SqlSession sqlSession = null;        try{            sqlSession = MybatisUtil.getSqlSession();            //事务开始（默认）            //读取StudentMapper.xml映射文件中的SQL语句            int i = sqlSession.insert(Student.class.getName()+".add",student);            System.out.println("本次操作影响了"+i+"行");            //事务提交            sqlSession.commit();        }catch(Exception e){            e.printStackTrace();            //事务回滚            sqlSession.rollback();            throw e;        }finally{            //MybatisUtil.closeSqlSession();        }    }    /**     * 根据ID查询学生     */    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();        }    }    /**     * 查询所有学生     */    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();        }    }    /**     * 更新学生     */    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();        }    }    /**     * 删除学生     */    public void delete(Student student) throws Exception{        SqlSession sqlSession = null;        try{            sqlSession = MybatisUtil.getSqlSession();            sqlSession.delete(Student.class.getName()+".delete",student);            //事务            sqlSession.commit();        }catch(Exception e){            e.printStackTrace();            // 回滚            sqlSession.rollback();            throw e;        }finally{            MybatisUtil.closeSqlSession();        }    }         public static void main(String[] args) throws Exception {        StudentDao dao = new StudentDao();//        dao.add(new Student(3,"美丽",70030.3));//        dao.add(new Student(4,"加油",70030.3));//        dao.add(new Student(5,"关系",70030.3));//        dao.add(new Student(6,"规律",70030.3));//        dao.add(new Student(7,"古蔺",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})                                    update students set name=#{name},sal=#{sal} where id=#{id}                    delete from students where id = #{id}