package com.tfy.itheima.dao.impl; import java.util.List; import org.apache.commons.dbutils.QueryRunner; import org.apache.commons.dbutils.handlers.BeanHandler; import org.apache.commons.dbutils.handlers.BeanListHandler; import com.tfy.itheima.domain.Student; import com.tfy.itheima.domain.Teacher; import com.tfy.itheima.jdbc.util.DbcpUtil; public class TeacherDaoImpl { private QueryRunner qr=new QueryRunner(DbcpUtil.getDataSource()); public void addTeacher(Teacher t){ try{ //保存教师的基本信息 String sql1="insert into teacher (id,name,salary) values(?,?,?)"; Object []params1={t.getId(),t.getName(),t.getSalary()}; qr.update(sql1, params1); //若是有学生的话,则保存学生的基本信息,并在第三方的表中创建关系 List<Student> students = t.getStudents(); if(students!=null && students.size()>0){ String sql2="insert into student (id,name,grade) values(?,?,?)"; String sql3="insert into teacher_student (teacher_id,student_id) values(?,?)"; Object [][]params2=new Object[students.size()][]; Object [][]params3=new Object[students.size()][]; for(int i=0;i<students.size();i++){ Student s = students.get(i); params2[i]=new Object[]{s.getId(),s.getName(),s.getGrade()}; params3[i]=new Object[]{t.getId(),s.getId()}; } qr.batch(sql2, params2); qr.batch(sql3, params3); } }catch(Exception e){ e.printStackTrace(); throw new RuntimeException(e); } } //把学生的基本信息查询出来 public Teacher findTeacherById(Integer teacherId){ try{ String sql1="select * from teacher where id=?"; Teacher t = qr.query(sql1, new BeanHandler<Teacher>(Teacher.class),teacherId); //查询学生基本信息 if(t!=null){ // String sql2="select s.* from student s ,teacher_student ts where s.id=ts.student_id and ts.teacher_id=?"; // String sql2="select s.* from student s inner join teacher_student ts on s.id=ts.student_id where ts.teacher_id=?"; String sql2="select * from student where id in(select student_id from teacher_student where teacher_id=?)"; List<Student> students = qr.query(sql2, new BeanListHandler<Student>(Student.class), teacherId); t.setStudents(students); } return t; }catch(Exception e){ e.printStackTrace(); throw new RuntimeException(e); } } }