db.java

我实习时候的设计

package cn.mcy.course;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import cn.yxh.util.DBConn;

public class DB 
{
	private Connection conn = null;//建立数据库连接对象
    private PreparedStatement stmt = null;//建立数据库操作对象
    private ResultSet rs = null;//建立结果集（用来接收从数据库中查询出来的数据）
    
    public void addcourse(Course c)
    {  
    	String sql="insert into course values(?,?,?,?,?,?,?)";
    	conn=DBConn.getConn();
    	try {
			stmt=conn.prepareStatement(sql);
			stmt.setString(1,c.getCourseid());
			stmt.setString(2,c.getCoursename());
			stmt.setString(3,c.getDepartment());
			stmt.setString(4,c.getAddress());
			stmt.setString(5,c.getTime());
			stmt.setInt(6,c.getNumber());
			stmt.setString(7,c.getTeachername());
			stmt.execute();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
    }
    public ResultSet showAllCourse()//显示所有课程记录
    {
    	String sql="select * from course";
    	conn=DBConn.getConn();
    	try {
			stmt=conn.prepareStatement(sql);
			rs=stmt.executeQuery();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return rs;
    }
    public ResultSet showCourse(String courseid)//以课程号为关键字返回课程信息
    {
    	conn=DBConn.getConn();
    	try {
			stmt=conn.prepareStatement("select * from course where courseid=?");
		    stmt.setString(1,courseid);
		    rs=stmt.executeQuery();
    	} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return rs;
    }
    public void saveUpdate(Course c)//更新记录
    {
    	conn=DBConn.getConn();
    	String sql="update course set coursename=?,department=?,address=?,time=?,number=?,teachername=? where courseid=?";
    	try {
			stmt=conn.prepareStatement(sql);
			stmt.setString(1,c.getCoursename());
			stmt.setString(2,c.getDepartment());
			stmt.setString(3,c.getAddress());
			stmt.setString(4,c.getTime());
			stmt.setInt(5,c.getNumber());
			stmt.setString(6,c.getTeachername());
			stmt.setString(7,c.getCourseid());
			stmt.execute();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
    }
   public void delCourse(String courseid)//删除课程记录
   {
	   conn=DBConn.getConn();
	   try {
		stmt=conn.prepareStatement("delete from course where courseid=?");
		stmt.setString(1,courseid);
		stmt.execute();
	} catch (SQLException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
   }
   public ResultSet search(String coursename)//将模糊查询的结果返回
   {
	   conn=DBConn.getConn();
	   try {
		stmt=conn.prepareStatement("select * from course where coursename like ?");
	   stmt.setString(1,"%"+coursename+"%");
	   rs=stmt.executeQuery();
	   } catch (SQLException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
	return rs;
   }
}