coursedao.java

使用struts+spring+JDBC 实现的学生选课管理系统

package bit.jeffy.service;

import java.util.Iterator;
import java.util.List;

import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapperResultReader;

import bit.jeffy.entity.Course;
import bit.jeffy.entity.Student;
import bit.jeffy.springdb.CourseRowMapper;

public class CourseDao{
	private JdbcTemplate jdbcTemplate;
	
	private String sql = "select count(*) from Course where COURSE_NO=?";
	private String sql_1 = "insert into Course(COURSE_NO,COURSE_NAME,TEACHER_ID) values(?,?,?)";
	private String sql_2 = "delete from Course where ID=?";
	private String sql_3 = "select * from Course";
	private String sql_4 = "select * from Course where course_no=?";
	private String sql_5 = "select * from Course where Course.ID not in(select selectcourse.COURSE_ID from selectcourse where STUDENT_ID=?)";
	private String sql_6 = "select * from Course where ID=?";
	
	public boolean validate(Course course){
        String course_no = course.getCourse_no();
		
		if( course_no.equals("") || course_no==null){
			return false;
		}
		
		Object[] ob = new Object[]{course_no};
		int nCount = 0;
		
		nCount = jdbcTemplate.queryForInt(sql,ob);
		if( nCount>0 ){
			return true;
		}else{
			return false;
		}
	}
	//老师开课
	public boolean save(Course c){
		String c_no = c.getCourse_no();
		String c_name = c.getCourse_name();
	    long tid = c.getTeacher_id();
	    
		if( c_no.equals("") || c_no==null || c_name.equals("") || c_name==null ||tid<0){
			return false;
		}
		
		Object ob[] = new Object[]{c_no,c_name,new Long(tid)};
		try{
			jdbcTemplate.update(sql_1,ob);
			return true;
		}catch(Exception e){
			return false;
		}
	}
	
	//老师删除开课
	public boolean delete(Course c){
		long cid = c.getId();
		
		if(cid < 0){
			return false;
		}
		
		Object ob[] = new Object[]{new Long(cid)};
		try{
			jdbcTemplate.update(sql_2,ob);
			return true;
		}catch(Exception e){
			return false;
		}
	}
	
	//读取课程集
	public List getAll(){
		return jdbcTemplate.query(sql_3,new RowMapperResultReader(new CourseRowMapper()));
	}
	
	//取出学生没有选过的课
	public List getAllByTid(Student stu){
		long sid = stu.getId();
		
		Object[] ob = new Object[]{new Long(sid)};
		return jdbcTemplate.query(sql_5,ob,new RowMapperResultReader(new CourseRowMapper()));
	}
	
	//按course_no号读取单门课程,在SelectCourseDao的LogScore中被调用
	public Course read(Course c){
		String c_no = c.getCourse_no();
		List list = null;
		Iterator it = null;
		Course rt = null;
		
		if(c_no.equals("") || c_no==null){
			return null;
		}
		
		Object[] ob = new Object[]{c_no};
		try{
			list = jdbcTemplate.query(sql_4,ob,new RowMapperResultReader(new CourseRowMapper()));
			it = list.iterator();
			if( it.hasNext()){
				rt = (Course)it.next();
			}
		}catch(Exception e){
			return null;
		}
		
		return rt;
	}
	
	//按ID号取出课程
	public Course readById(Course c){
		long cid = c.getId();
		List list = null;
		Iterator it = null;
		Course rt = null;
		
		if(cid<0){
			return null;
		}
		
		Object[] ob = new Object[]{new Long(cid)};
		try{
			list = jdbcTemplate.query(sql_6,ob,new RowMapperResultReader(new CourseRowMapper()));
			it = list.iterator();
			if( it.hasNext()){
				rt = (Course)it.next();
			}
		}catch(Exception e){
			return null;
		}
		
		return rt;
	}

	public JdbcTemplate getJdbcTemplate() {
		return jdbcTemplate;
	}

	public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
		this.jdbcTemplate = jdbcTemplate;
	}
}