学生管理系统的增删改查

发布时间：2023-10-19 15:30

目录

一、数据库的设计

 二、底层代码1（实体类以及dao方法）

三、底层代码二（servlet）

四、界面代码

使用工具：MySQL和eclipse

目标需求：

1.利用MySQL建4张表 分别为 学生表 教员表 班级表 爱好表

2.要求带条件的模糊查询（两个下拉框以及一个复选框）和分页

3.新增功能

4.修改界面，值回显的问题（显示已选中的爱好）

5.删除功能

爱好表（1代表篮球 2代表足球 3代表唱歌 4代表跳舞）

一、数据库的设计

\"学生管理系统的增删改查_第1张图片\"

tb_class

\"学生管理系统的增删改查_第2张图片\"

tb_habby

\"学生管理系统的增删改查_第3张图片\"

tb_stu

\"学生管理系统的增删改查_第4张图片\"

tb_teacher

\"学生管理系统的增删改查_第5张图片\"

 二、底层代码1（实体类以及dao方法）

com.cdl.utils包下

#oracle9i
#driver=oracle.jdbc.driver.OracleDriver
#url=jdbc:oracle:thin:@localhost:1521:orcl
#user=scott
#pwd=123


#sql2005
#driver=com.microsoft.sqlserver.jdbc.SQLServerDriver
#url=jdbc:sqlserver://localhost:1433;DatabaseName=test1
#user=sa
#pwd=123


#sql2000
#driver=com.microsoft.jdbc.sqlserver.SQLServerDriver
#url=jdbc:microsoft:sqlserver://localhost:1433;databaseName=unit6DB
#user=sa
#pwd=888888


#mysql
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/0614?useUnicode=true&characterEncoding=UTF-8&useSSL=false
user=root
pwd=123456




package com.cdl.utils;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

/**
 * 提供了一组获得或关闭数据库对象的方法
 * 
 */
public class DBHelper {
	private static String driver;
	private static String url;
	private static String user;
	private static String password;

	static {// 静态块执行一次，加载 驱动一次
		try {
			InputStream is = DBHelper.class
					.getResourceAsStream(\"config.properties\");

			Properties properties = new Properties();
			properties.load(is);

			driver = properties.getProperty(\"driver\");
			url = properties.getProperty(\"url\");
			user = properties.getProperty(\"user\");
			password = properties.getProperty(\"pwd\");

			Class.forName(driver);
		} catch (Exception e) {
			e.printStackTrace();
			throw new RuntimeException(e);
		}
	}

	/**
	 * 获得数据连接对象
	 * 
	 * @return
	 */
	public static Connection getConnection() {
		try {
			Connection conn = DriverManager.getConnection(url, user, password);
			return conn;
		} catch (SQLException e) {
			e.printStackTrace();
			throw new RuntimeException(e);
		}
	}

	public static void close(ResultSet rs) {
		if (null != rs) {
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
				throw new RuntimeException(e);
			}
		}
	}

	public static void close(Statement stmt) {
		if (null != stmt) {
			try {
				stmt.close();
			} catch (SQLException e) {
				e.printStackTrace();
				throw new RuntimeException(e);
			}
		}
	}

	public static void close(Connection conn) {
		if (null != conn) {
			try {
				conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
				throw new RuntimeException(e);
			}
		}
	}

	public static void close(Connection conn, Statement stmt, ResultSet rs) {
		close(rs);
		close(stmt);
		close(conn);
	}

	public static boolean isOracle() {
		return \"oracle.jdbc.driver.OracleDriver\".equals(driver);
	}

	public static boolean isSQLServer() {
		return \"com.microsoft.sqlserver.jdbc.SQLServerDriver\".equals(driver);
	}
	
	public static boolean isMysql() {
		return \"com.mysql.jdbc.Driver\".equals(driver);
	}

	public static void main(String[] args) {
		Connection conn = DBHelper.getConnection();
		DBHelper.close(conn);
		/*System.out.println(\"isOracle：\" + isOracle());
		System.out.println(\"isSQLServer：\" + isSQLServer());*/
		System.out.println(\"isMysql：\" + isMysql());
		System.out.println(\"数据库连接(关闭)成功\");
	}
}

com.cdl.entity

package com.cdl.entity;

import java.io.Serializable;

/**
 * 实体类：班级类
 * @author 陈冬丽
 *
 */
public class Class implements Serializable{
	//防止序列化与反序列化
	private static final long serialVersionUID = 1L;
	private  int cid;//班级编号
	private String cname;//班级姓名
	
	public int getCid() {
		return cid;
	}
	public void setCid(int cid) {
		this.cid = cid;
	}
	public String getCname() {
		return cname;
	}
	public void setCname(String cname) {
		this.cname = cname;
	}
	
	public Class() {
		// TODO Auto-generated constructor stub
	}
	public Class(int cid, String cname) {
		this.cid = cid;
		this.cname = cname;
	}
	
	public Class(String cname) {
		this.cname = cname;
	}
	@Override
	public String toString() {
		return \"Class [cid=\" + cid + \", cname=\" + cname + \"]\";
	}
	
	
	
}

package com.cdl.entity;

import java.io.Serializable;

/**
 * 实体类：爱好类
 * @author 陈冬丽
 *
 */
public class Habby implements Serializable{
	//防止序列化与反序列化
	private static final long serialVersionUID = 1L;
	private String hid;//爱好编号
	private String hname;//爱好名称
	
	public String getHid() {
		return hid;
	}
	public void setHid(String hid) {
		this.hid = hid;
	}
	public String getHname() {
		return hname;
	}
	public void setHname(String hname) {
		this.hname = hname;
	}
	
	public Habby() {
		// TODO Auto-generated constructor stub
	}
	public Habby(String hid, String hname) {
		this.hid = hid;
		this.hname = hname;
	}
	
	public Habby( String hname) {
		this.hname = hname;
	}
	@Override
	public String toString() {
		return \"Habby [hid=\" + hid + \", hname=\" + hname + \"]\";
	}
	
	
	
}

package com.cdl.entity;

import java.io.Serializable;
import java.util.List;

/**
 * 实体类：学生类
 * @author 陈冬丽
 *
 */
public class Student implements Serializable{
	//防止序列化与反序列化
	private static final long serialVersionUID = 1L;
	private int sid;//学生编号
	private String sname;//学生姓名
	private Class c;//班级
	private Habby h;//爱好
	private Teacher tea;//老师
	private String ss;
	private List ls;
	
	
	public String getSs() {
		return ss;
	}
	public void setSs(String ss) {
		this.ss = ss;
	}
	public List getLs() {
		return ls;
	}
	public void setLs(List ls) {
		this.ls = ls;
	}
	public int getSid() {
		return sid;
	}
	public void setSid(int sid) {
		this.sid = sid;
	}
	public String getSname() {
		return sname;
	}
	public void setSname(String sname) {
		this.sname = sname;
	}
	public Class getC() {
		return c;
	}
	public void setC(Class c) {
		this.c = c;
	}
	public Habby getH() {
		return h;
	}
	public void setH(Habby h) {
		this.h = h;
	}
	public Teacher getTea() {
		return tea;
	}
	public void setTea(Teacher tea) {
		this.tea = tea;
	}
	
	public Student() {
		// TODO Auto-generated constructor stub
	}
	public Student(int sid, String sname, Class c, Habby h, Teacher tea, String ss, List ls) {
		this.sid = sid;
		this.sname = sname;
		this.c = c;
		this.h = h;
		this.tea = tea;
		this.ss = ss;
		this.ls = ls;
	}
	public Student(int sid, String sname, Class c,Teacher tea, String ss) {
		this.sid = sid;
		this.sname = sname;
		this.c = c;
		this.tea = tea;
		this.ss = ss;
	}
	@Override
	public String toString() {
		return \"Student [sid=\" + sid + \", sname=\" + sname + \", c=\" + c + \", h=\" + h + \", tea=\" + tea + \", ss=\" + ss
				+ \", ls=\" + ls + \"]\";
	}
	
	
	
	
	
	
	
}

package com.cdl.entity;

import java.io.Serializable;

/**
 * 实体类：教员类
 * @author 陈冬丽
 *
 */
public class Teacher implements Serializable{
	//防止序列化与反序列化
	private static final long serialVersionUID = 1L;
	private int tid;//教员编号
	private String tname;//教员姓名
	private Class c;//所教班级
	public int getTid() {
		return tid;
	}
	public void setTid(int tid) {
		this.tid = tid;
	}
	public String getTname() {
		return tname;
	}
	public void setTname(String tname) {
		this.tname = tname;
	}
	public Class getC() {
		return c;
	}
	public void setC(Class c) {
		this.c = c;
	}
	
	public Teacher() {
		// TODO Auto-generated constructor stub
	}
	public Teacher(int tid, String tname, Class c) {
		this.tid = tid;
		this.tname = tname;
		this.c = c;
	}
	
	public Teacher( String tname, Class c) {
		this.tname = tname;
		this.c = c;
	}
	@Override
	public String toString() {
		return \"Teacher [tid=\" + tid + \", tname=\" + tname + \", c=\" + c + \"]\";
	}
	
	
	
}

com.cdl.dao

package com.cdl.dao;

import java.util.List;

import com.cdl.entity.Student;
/**
 * 数据库访问层设计类
 * @author 陈冬丽
 *
 */
public interface IStuDao {
	
	/**
	 * 查询单个
	 * @param sid 学生编号
	 * @return 学生对象
	 */
	public Student getStu(int sid) ;
	
	
	/**
	 * 查询所有
	 * @return 查询的结果集合
	 */
	public List getAll();
	
	/**
	 * 模糊查询
	 * @param colName 要查询的列名
	 * @param str 关键字
	 * @return 对象
	 */
	public List getMH(String ctr,String htr, String str,int pageIndex,int pageSize);
	
	/**
	 * 增加学生
	 * @param stu 学生对象
	 * @return 影响行数
	 */
	public int addStu(Student stu);
	
	/**
	 * 删除学生
	 * @param sid 学生编号
	 * @return 影响行数
	 */
	public int delStu(int sid);
	
	/**
	 * 修改学生 
	 * @param stu 要修改的对象
	 * @param sid 学生编号
	 * @return 影响行数
	 */
	public int upStu(Student stu,int sid);
	
	/**
	 * 总行数
	 * @return 行数
	 */
	public int getRows(String str);
	
	
	
}

package com.cdl.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

import com.cdl.entity.Class;
import com.cdl.entity.Habby;
import com.cdl.entity.Student;
import com.cdl.utils.DBHelper;

/**
 * 数据库访问层
 * @author 陈冬丽
 *
 */
public class StuDao implements IStuDao{
	
	//三兄弟
	Connection con = null;
	PreparedStatement ps =null;
	ResultSet rs = null;
	
	
	public Student getStu(int sid) {
		Student stu = new Student();
		try {
			//获得连接
			con = DBHelper.getConnection();
			//定义sql语句
			String sql = \"select * from tb_stu where sid=?\";
			//获得执行对象
			ps=con.prepareStatement(sql);
			//给占位符赋值
			ps.setInt(1, sid);
			//给rs赋值
			rs=ps.executeQuery();
			//判断
			if(rs.next()) {
				stu.setSid(rs.getInt(1));
				stu.setSname(rs.getString(2));
				stu.setC(new ClassDao().getClz(rs.getInt(3)));
				//stu.setH(new HobbyDao().getHob(rs.getInt(4)));
				stu.setSs(rs.getString(4));
				stu.setTea(new TeaDao().getTea(rs.getInt(5)));
			}
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}finally {
			DBHelper.close(con, ps, rs);
		}
		return stu;
	}
	
	
	@Override
	public List getAll() {
		List ls = new ArrayList();
		try {
			//获得连接
			con = DBHelper.getConnection();
			//定义sql语句
			String sql = \"select * from tb_stu\";
			//获得执行对象
			ps=con.prepareStatement(sql);
			//给集合赋值
			rs=ps.executeQuery();
			//遍历
			while(rs.next()) {
				List list = new ArrayList<>();
				//实例化一个对象
				Student stu = new Student();
				stu.setSid(rs.getInt(1));
				stu.setSname(rs.getString(2));
				stu.setC(new ClassDao().getClz(rs.getInt(3)));
				//stu.setH(new HobbyDao().getHob(rs.getInt(4)));
				//分割
				String hob = rs.getString(4);
				//System.out.println(rs.getString(4));
				//用逗号分割
				String [] ss = hob.split(\",\");
				for (String so : ss) {
					IHobbyDao ihd = new HobbyDao();
					Habby h = ihd.getHob(Integer.parseInt(so));
					list.add(h);
				}
				stu.setLs(list);
				stu.setTea(new TeaDao().getTea(rs.getInt(5)));
				//加进去
				ls.add(stu);
			}
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}
		finally {
			DBHelper.close(con, ps, rs);
		}
		return ls;
	}

	@Override
	public List getMH(String ctr, String htr,String str,int pageIndex,int pageSize) {
		List ls = new ArrayList<>();
		int a = (pageIndex-1)*pageSize;
		int b = pageSize;
		try {
			//获得连接
			con = DBHelper.getConnection();
			//定义sql语句
			String sql = \"select * from tb_stu where hid like \'%\"+htr+\"%\' and tid like \'%\"+str+\"%\' and cid like \'%\"+ctr+\"%\' limit ?,?\";
			//获得执行对象
			ps=con.prepareStatement(sql);
			ps.setInt(1, a);
			ps.setInt(2, b);
			//给集合赋值
			rs=ps.executeQuery();
			//遍历
			if(rs.next()) {
				List list = new ArrayList<>();
				//实例化一个对象
				Student stu = new Student();
				stu.setSid(rs.getInt(1));
				stu.setSname(rs.getString(2));
				stu.setC(new ClassDao().getClz(rs.getInt(3)));
				//stu.setH(new HobbyDao().getHob(rs.getInt(4)));
				//分割
				String hob = rs.getString(4);
				//System.out.println(rs.getString(4));
				//用逗号分割
				String [] ss = hob.split(\",\");
				for (String so : ss) {
					IHobbyDao ihd = new HobbyDao();
					//调用单个查询方法
					Habby h = ihd.getHob(Integer.parseInt(so));
					list.add(h);
				}
				stu.setLs(list);
				stu.setTea(new TeaDao().getTea(rs.getInt(5)));
				//加进去
				ls.add(stu);
			}
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}
		finally {
			DBHelper.close(con, ps, rs);
		}
		return ls;
	}

	@Override
	public int addStu(Student stu) {
		int n = 0;
		try {
			//获得连接
			con = DBHelper.getConnection();
			//定义sql语句
			String sql = \"insert into tb_stu(sid,sname,cid,hid,tid) values(?,?,?,?,?)\";
			//获得执行对象
			ps=con.prepareStatement(sql);
			//给占位符赋值
			ps.setInt(1, stu.getSid());
			ps.setString(2, stu.getSname());
			ps.setInt(3,stu.getC().getCid());
			ps.setString(4, stu.getSs());
			ps.setInt(5,stu.getTea().getTid());
			//给n赋值
			n=ps.executeUpdate();
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}finally {
			DBHelper.close(con, ps, rs);
		}
		return n;
	}

	@Override
	public int delStu(int sid) {
		int n = 0;
		try {
			//获得连接
			con = DBHelper.getConnection();
			//定义sql语句
			String sql = \"delete from tb_stu where sid=?\";
			//获得执行对象
			ps=con.prepareStatement(sql);
			//给占位符赋值
			ps.setInt(1, sid);
			//给n赋值
			n=ps.executeUpdate();
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}finally {
			DBHelper.close(con, ps, rs);
		}
		return n;
	}

	@Override
	public int upStu(Student stu, int sid) {
		int  n = 0;
		try {
			//获得连接
			con = DBHelper.getConnection();
			//定义sql语句
			String sql = \"update tb_stu set sname=?,cid=?,hid=?,tid=? where sid=?\";
			//获得执行对象
			ps=con.prepareStatement(sql);
			//给占位符赋值
			ps.setString(1, stu.getSname());
			ps.setInt(2, stu.getC().getCid());
			ps.setString(3, stu.getSs());
			ps.setInt(4, stu.getTea().getTid());
			ps.setInt(5, sid);
			//给n赋值
			n=ps.executeUpdate();
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}finally {
			DBHelper.close(con, ps, rs);
		}
		return n;
	}
	
	

	@Override
	public int getRows(String str) {
		int n = 0;
		try {
			con = DBHelper.getConnection();
			String sql = \"select count(*) from ?\";
			ps=con.prepareStatement(sql);
			ps.setString(1, str);
			rs=ps.executeQuery();
			if(rs.next()) {
				n=rs.getInt(1);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			DBHelper.close(con, ps, null);
		}
		return n;
	}
	
	public static void main(String[] args) {
		StuDao stu = new StuDao();
//		System.out.println(123);
		/*List sd = stu.getAll();
		for (Student student : sd) {
			System.out.println(student);
		}*/
		/*Student stu2 = stu.getStu(3);
		System.out.println(stu2);*/
		/*List mh = stu.getMH(\"sname\", \"三\", 2, 2);
		for (Student student : mh) {
			System.out.println(student+\"=====================\");
		}*/
		List mh = stu.getMH(\"278\", \"1\", \"2202\", 1, 2);
		for (Student student : mh) {
			System.out.println(student+\"=================\");
		}
		
	}
	
}

package com.cdl.dao;
/**
 * 数据访问层接口类
 * @author 陈冬丽
 *
 */

import java.util.List;

import com.cdl.entity.Teacher;

public interface ITeacDao {
	/**
	 * 查询单个教员
	 * @param tid 教员编号
	 * @return 教员对象
	 */
	public Teacher getTea(int tid);
	
	/**
	 * 查询所有教员
	 * @return
	 */
	public List getAll();
}

package com.cdl.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

import com.cdl.entity.Teacher;
import com.cdl.utils.DBHelper;

/**
 * 业务逻辑层
 * @author 陈冬丽
 *
 */
public class TeaDao implements ITeacDao{
	
	//三兄弟
	Connection con = null;
	PreparedStatement ps =null;
	ResultSet rs = null;

	@Override
	public Teacher getTea(int tid) {
		Teacher tea = new Teacher();
		try {
			//获得连接
			con = DBHelper.getConnection();
			//定义sql语句
			String sql = \"select * from tb_teacher where tid=?\";
			//获得执行对象
			ps=con.prepareStatement(sql);
			//给占位符赋值
			ps.setInt(1, tid);
			//给rs赋值
			rs=ps.executeQuery();
			//判断
			if(rs.next()) {
				tea.setTid(rs.getInt(1));
				tea.setTname(rs.getString(2));
				tea.setC(new ClassDao().getClz(3));
			}
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}
		finally {
			DBHelper.close(con, ps, rs);
		}
		return tea;
	}

	@Override
	public List getAll() {
		List list = new ArrayList();
		try {
			//获得连接
			con = DBHelper.getConnection();
			//定义sql语句
			String sql = \"select * from tb_teacher\";
			//获得执行对象
			ps=con.prepareStatement(sql);
			//给rs赋值
			rs=ps.executeQuery();
			//判断
			while(rs.next()) {
				Teacher tea = new Teacher();
				tea.setTid(rs.getInt(1));
				tea.setTname(rs.getString(2));
				tea.setC(new ClassDao().getClz(rs.getInt(3)));
				//加进去
				list.add(tea);
			}
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}
		finally {
			DBHelper.close(con, ps, rs);
		}
		return list;
	}
	
	/*public static void main(String[] args) {
		TeaDao td = new TeaDao();
		Teacher tea = td.getTea(2201);
		System.out.println(tea);
	}*/
	
}

package com.cdl.dao;
/**
 * 数据库访问层接口类
 * @author 陈冬丽
 *
 */

import java.util.List;

import com.cdl.entity.Habby;

public interface IHobbyDao {
	/**
	 * 查询单个
	 * @param hid 爱好编号
	 * @return 爱好的对象
	 */
	public Habby getHob(int hid);
	
	/**
	 * 查询所有
	 * @return 爱好的集合
	 */
	public List getAll();
}

package com.cdl.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

import com.cdl.entity.Habby;
import com.cdl.utils.DBHelper;

/**
 * 数据库访问层
 * @author 陈冬丽
 *
 */
public class HobbyDao implements IHobbyDao{

	//三兄弟
	Connection con = null;
	PreparedStatement ps =null;
	ResultSet rs = null;
		
	
	@Override
	public Habby getHob(int hid) {
		Habby h = new Habby();
		try {
			//获得连接
			con = DBHelper.getConnection();
			//定义sql语句
			String sql = \"select * from tb_habby where hid=?\";
			//获得执行对象
			ps=con.prepareStatement(sql);
			//给占位符赋值
			ps.setInt(1, hid);
			//给rs赋值
			rs=ps.executeQuery();
			//判断
			if(rs.next()) {
				h.setHid(rs.getString(1));
				h.setHname(rs.getString(2));
			}
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}
		finally {
			DBHelper.close(con, ps, rs);
		}
		return h;
	}


	@Override
	public List getAll() {
		List list = new ArrayList();
		try {
			//获得连接
			con = DBHelper.getConnection();
			//定义sql语句
			String sql = \"select * from tb_habby\";
			//获得执行对象
			ps=con.prepareStatement(sql);
			//给rs赋值
			rs=ps.executeQuery();
			//遍历
			while(rs.next()) {
				Habby h = new Habby();
				h.setHid(rs.getString(1));
				h.setHname(rs.getString(2));
				//加进去
				list.add(h);
			}
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}finally {
			DBHelper.close(con, ps, rs);
		}
		return list;
	}
	
}

package com.cdl.dao;
/**
 * 数据库访问层
 * @author 陈冬丽
 *
 */

import java.util.List;

import com.cdl.entity.Class;

public interface IClassDao {
	/**
	 * 查询单个班级
	 * @return 班级对象
	 */
	public Class  getClz(int cid);
	
	/**
	 * 查询所有
	 * @return 班级和集合
	 */
	public List getAll();
}

package com.cdl.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

import com.cdl.entity.Class;
import com.cdl.utils.DBHelper;

/**
 * 数据库访问层
 * @author 陈冬丽
 *
 */
public class ClassDao implements IClassDao{

	//三兄弟
	Connection con = null;
	PreparedStatement ps =null;
	ResultSet rs = null;
	
	@Override
	public Class getClz(int cid) {
		Class clz = new Class();
		try {
			//获得连接
			con = DBHelper.getConnection();
			//定义sql语句
			String sql = \"select * from tb_class where cid=?\";
			//获得执行对象
			ps=con.prepareStatement(sql);
			//给占位符赋值
			ps.setInt(1, cid);
			//给rs赋值
			rs=ps.executeQuery();
			//判断
			if(rs.next()) {
				clz.setCid(rs.getInt(1));
				clz.setCname(rs.getString(2));
			}
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}finally {
			DBHelper.close(con, ps, rs);
		}
		return clz;
	}

	@Override
	public List getAll() {
		List list = new ArrayList();
		try {
			//获得连接
			con = DBHelper.getConnection();
			//定义sql语句
			String sql = \"select * from tb_class\";
			//获得执行对象
			ps=con.prepareStatement(sql);
			//给rs赋值
			rs=ps.executeQuery();
			//遍历
			while(rs.next()) {
				Class c = new Class();
				c.setCid(rs.getInt(1));
				c.setCname(rs.getString(2));
				//加进去
				list.add(c);
			}
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}finally {
			DBHelper.close(con, ps, rs);
		}
		return list;
	}
	
	/*public static void main(String[] args) {
		ClassDao cd = new ClassDao();
		List c = cd.getAll();
		System.out.println(c);
	}*/
	
}

com.cdl.biz

package com.cdl.biz;

import java.util.List;

import com.cdl.entity.Student;

/**
 * 业务逻辑层设计类
 * @author 陈冬丽
 *
 */
public interface IStuBiz {
	
	/**
	 * 查询单个
	 * @param sid 学生编号
	 * @return 学生对象
	 */
	public Student getStu(int sid) ;
	
	
	/**
	 * 查询所有
	 * @return 查询的结果集合
	 */
	public List getAll();
	
	/**
	 * 模糊查询
	 * @param colName 要查询的列名
	 * @param str 关键字
	 * @return 对象
	 */
	public List getMH(String ctr,String htr, String str,int pageIndex,int pageSize);
	/**
	 * 增加学生
	 * @param stu 学生对象
	 * @return 影响行数
	 */
	public int addStu(Student stu);
	
	/**
	 * 删除学生
	 * @param sid 学生编号
	 * @return 影响行数
	 */
	public int delStu(int sid);
	
	/**
	 * 修改学生 
	 * @param stu 要修改的对象
	 * @param sid 学生编号
	 * @return 影响行数
	 */
	public int upStu(Student stu,int sid);
	
	/**
	 * 总行数
	 * @return
	 */
	public int getRows(String str);
}

package com.cdl.biz;
/**
 * 业务逻辑层
 * @author 陈冬丽
 *
 */

import java.util.List;

import com.cdl.dao.IStuDao;
import com.cdl.dao.StuDao;
import com.cdl.entity.Student;

public class StuBiz implements IStuBiz{
	//调用数据库访问层
	IStuDao isd = new StuDao();

	@Override
	public List getAll() {
		// TODO Auto-generated method stub
		return isd.getAll();
	}

	@Override
	public int addStu(Student stu) {
		// TODO Auto-generated method stub
		return isd.addStu(stu);
	}

	@Override
	public int delStu(int sid) {
		// TODO Auto-generated method stub
		return isd.delStu(sid);
	}

	@Override
	public int upStu(Student stu, int sid) {
		// TODO Auto-generated method stub
		return isd.upStu(stu, sid);
	}

	@Override
	public Student getStu(int sid) {
		// TODO Auto-generated method stub
		return isd.getStu(sid);
	}

	@Override
	public List getMH(String ctr, String htr, String str, int pageIndex, int pageSize) {
		// TODO Auto-generated method stub
		return isd.getMH(ctr, htr, str, pageIndex, pageSize);
	}

	@Override
	public int getRows(String str) {
		// TODO Auto-generated method stub
		return isd.getRows(str);
	}

	



	
	
	
	
}

package com.cdl.biz;
/**
 * 业务逻辑层接口类
 * @author 陈冬丽
 *
 */

import java.util.List;

import com.cdl.entity.Teacher;

public interface ITeacBiz {
	/**
	 * 查询单个教员
	 * @param tid 教员编号
	 * @return 教员对象
	 */
	public Teacher getTea(int tid);
	
	/**
	 * 查询所有教员
	 * @return
	 */
	public List getAll();
	
}

package com.cdl.biz;
/**
 * 业务逻辑层
 * @author 陈冬丽
 *
 */

import java.util.List;

import com.cdl.dao.ITeacDao;
import com.cdl.dao.TeaDao;
import com.cdl.entity.Teacher;

public class TeaBiz implements ITeacBiz{
	//调用数据库访问层
	ITeacDao itd = new TeaDao();

	@Override
	public Teacher getTea(int tid) {
		// TODO Auto-generated method stub
		return itd.getTea(tid);
	}

	@Override
	public List getAll() {
		// TODO Auto-generated method stub
		return itd.getAll();
	}
	
	
}

package com.cdl.biz;
/**
 * 业务逻辑层接口类
 * @author 陈冬丽
 *
 */

import java.util.List;

import com.cdl.entity.Habby;

public interface IHobbyBiz {
	/**
	 * 查询单个
	 * @param hid 爱好编号
	 * @return 爱好的对象
	 */
	public Habby getHob(int hid);
	
	/**
	 * 查询所有
	 * @return 爱好的集合
	 */
	public List getAll();
}

package com.cdl.biz;
/**
 * 业务逻辑层
 * @author 陈冬丽
 *
 */

import java.util.List;

import com.cdl.dao.HobbyDao;
import com.cdl.dao.IHobbyDao;
import com.cdl.entity.Habby;

public class HobbyBiz implements IHobbyBiz{
	//调用数据库访问层
	IHobbyDao ihd = new HobbyDao();

	@Override
	public Habby getHob(int hid) {
		// TODO Auto-generated method stub
		return ihd.getHob(hid);
	}

	@Override
	public List getAll() {
		// TODO Auto-generated method stub
		return ihd.getAll();
	}
	
}

package com.cdl.biz;

import java.util.List;

import com.cdl.entity.Class;
/**
 * 业务逻辑层接口类
 * @author 陈冬丽
 *
 */
public interface IClassBiz {
	/**
	 * 查询单个班级
	 * @return 班级对象
	 */
	public Class  getClz(int cid);
	
	/**
	 * 查询所有
	 * @return 班级和集合
	 */
	public List getAll();
}

package com.cdl.biz;
/***
 * 业务逻辑层
 * @author 陈冬丽
 *
 */

import java.util.List;

import com.cdl.dao.ClassDao;
import com.cdl.dao.IClassDao;
import com.cdl.entity.Class;

public class ClassBiz implements IClassBiz{
	//调用数据库访问层
	IClassDao icd = new ClassDao();

	@Override
	public Class getClz(int cid) {
		// TODO Auto-generated method stub
		return icd.getClz(cid);
	}

	@Override
	public List getAll() {
		// TODO Auto-generated method stub
		return icd.getAll();
	}
	
}

三、底层代码二（servlet）

com.cdl.servlet

package com.cdl.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.cdl.biz.ClassBiz;
import com.cdl.biz.HobbyBiz;
import com.cdl.biz.IClassBiz;
import com.cdl.biz.IHobbyBiz;
import com.cdl.biz.IStuBiz;
import com.cdl.biz.ITeacBiz;
import com.cdl.biz.StuBiz;
import com.cdl.biz.TeaBiz;
import com.cdl.entity.Class;
import com.cdl.entity.Habby;
import com.cdl.entity.Student;
import com.cdl.entity.Teacher;

/**
 * 主界面绑值以及模糊查询
 */
@WebServlet(\"/index.do\")
public class IndexServlet extends HttpServlet {
	
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}

	
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//设置编码方式
		request.setCharacterEncoding(\"utf-8\");
		response.setCharacterEncoding(\"utf-8\");
		response.setContentType(\"text/html; charset=UTF-8\");
		
		//获取out
		PrintWriter out = response.getWriter();
		
		//调用biz层
		IStuBiz stb = new StuBiz();
		ITeacBiz itb = new TeaBiz();
		IClassBiz icb = new ClassBiz();
		IHobbyBiz ihb = new HobbyBiz();
		
		//定义页码页数
		int pageIndex=1;
		int pageSize=2;
		//接收表单值
		String cid = request.getParameter(\"ctr\");//班级
		String hid = request.getParameter(\"htr\");//爱好
		String tid = request.getParameter(\"str\");//教员
		
		if(tid==null) {
			tid=\"\";
		}
		if(hid==null) {
			hid=\"\";
		}
		if(cid==null) {
			cid=\"\";
		}
		
		String pid = request.getParameter(\"pid\");
		if(pid!=null) {
			pageIndex=Integer.parseInt(pid);
		}
		
		//select * from tb_teacher where tid like \'%\"+hid+\"%\'
		int rows = stb.getRows(\"  tb_stu where hid like \'%\"+hid+\"%\' and tid like \'%\"+tid+\"%\' and cid like \'%\"+cid+\"%\' \");
		int max = rows/pageSize;
		if(rows%pageSize!=0) {
			max++;
		}
		if(max==0) {
			max=1;
		}
		
		//调用方法
		List mytea = itb.getAll();
		List myclz = icb.getAll();
		List myh = ihb.getAll();
		List myls = stb.getMH(cid, hid, tid, pageIndex,pageSize);
//		Student stu = new Student();
//		List ls = stu.getLs();
//		String aa = \"\";
//		for (Habby habby : ls) {
//			aa+=habby+\",\";
//		}
		
		/*int rows = */
		request.setAttribute(\"mytea\", mytea);
		request.setAttribute(\"myclz\", myclz);
		request.setAttribute(\"myh\", myh);
		request.setAttribute(\"max\", max);
		request.setAttribute(\"pageIndex\", pageIndex);
		request.setAttribute(\"myls\", myls);
		//判断
		request.getRequestDispatcher(\"index.jsp\").forward(request, response);
		/*if(myls!=null) {
			
			
		}
		else {
			System.out.println(\"检查dao方法\");
		}*/
		
	}

}


package com.cdl.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.cdl.biz.ClassBiz;
import com.cdl.biz.HobbyBiz;
import com.cdl.biz.IClassBiz;
import com.cdl.biz.IHobbyBiz;
import com.cdl.biz.IStuBiz;
import com.cdl.biz.ITeacBiz;
import com.cdl.biz.StuBiz;
import com.cdl.biz.TeaBiz;
import com.cdl.entity.Class;
import com.cdl.entity.Habby;
import com.cdl.entity.Student;
import com.cdl.entity.Teacher;

/**
 * 增加前增加界面的绑值
 */
@WebServlet(\"/add1.do\")
public class AddIndexServlet extends HttpServlet {
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}

	
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//设置编码方式
		request.setCharacterEncoding(\"utf-8\");
		response.setCharacterEncoding(\"utf-8\");
		response.setContentType(\"text/html; charset=UTF-8\");
		
		//获取out
		PrintWriter out = response.getWriter();
		
		
		//调用biz层
		IStuBiz stb = new StuBiz();
		ITeacBiz itb = new TeaBiz();
		IClassBiz icb = new ClassBiz();
		IHobbyBiz ihb = new HobbyBiz();
		//调用方法
		List myls = stb.getAll();
		List mytea = itb.getAll();
		List myclz = icb.getAll();
		List myh = ihb.getAll();
		
		request.setAttribute(\"mytea\", mytea);
		request.setAttribute(\"myclz\", myclz);
		request.setAttribute(\"myh\", myh);
		//判断
		if(myls!=null) {
			request.setAttribute(\"myls\", myls);
			request.getRequestDispatcher(\"add.jsp\").forward(request, response);
		}
		else {
			System.out.println(\"检查dao方法\");
		}
		
	}

}

package com.cdl.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.cdl.biz.ClassBiz;
import com.cdl.biz.HobbyBiz;
import com.cdl.biz.IClassBiz;
import com.cdl.biz.IHobbyBiz;
import com.cdl.biz.IStuBiz;
import com.cdl.biz.ITeacBiz;
import com.cdl.biz.StuBiz;
import com.cdl.biz.TeaBiz;
import com.cdl.entity.Class;
import com.cdl.entity.Habby;
import com.cdl.entity.Student;
import com.cdl.entity.Teacher;

/**
 * 执行增加
 */
@WebServlet(\"/add.do\")
public class AddServlet extends HttpServlet {
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}

	
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//设置编码方式
		request.setCharacterEncoding(\"utf-8\");
		response.setCharacterEncoding(\"utf-8\");
		response.setContentType(\"text/html; charset=UTF-8\");
		
		//获取out
		PrintWriter out = response.getWriter();
		
		//接收值
		String sid = request.getParameter(\"sid\");
		String sname = request.getParameter(\"sname\");
		//System.out.println(sid+sname+\"======================\");
		String tid = request.getParameter(\"tname\");
		String cid = request.getParameter(\"cname\");
		
		String [] id = request.getParameterValues(\"hname\");
		String hb = \"\";
		for (String string : id) {
			hb+=string;
		}
		//System.out.println(hb+\"==============\"+id);
		//调用biz层
		ITeacBiz itb = new TeaBiz();
		Teacher tea = itb.getTea(Integer.valueOf(tid));
		
		IClassBiz icb = new ClassBiz();
		Class clz = icb.getClz(Integer.valueOf(cid));
		
		IStuBiz stb = new StuBiz();
		Student stu = new Student(Integer.parseInt(sid), sname, clz, tea,hb);
		int n = stb.addStu(stu);
		
		
		//判断
		if(n>0) {
			out.print(\"\");
		}
		else {
			System.out.println(\"检查dao方法\");
		}
		
	}

}

package com.cdl.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.cdl.biz.ClassBiz;
import com.cdl.biz.IClassBiz;
import com.cdl.biz.IStuBiz;
import com.cdl.biz.ITeacBiz;
import com.cdl.biz.StuBiz;
import com.cdl.biz.TeaBiz;
import com.cdl.entity.Class;
import com.cdl.entity.Student;
import com.cdl.entity.Teacher;

/**
 * 执行删除
 */
@WebServlet(\"/delete.do\")
public class DeleteServlet extends HttpServlet {
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}

	
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//设置编码方式
		request.setCharacterEncoding(\"utf-8\");
		response.setCharacterEncoding(\"utf-8\");
		response.setContentType(\"text/html; charset=UTF-8\");
		
		//获取out
		PrintWriter out = response.getWriter();
		
		//接收值
		String sid = request.getParameter(\"sid\");
		//System.out.println(sid+\"===================\");
		
		//调用biz层
		IStuBiz stb = new StuBiz();
		int n = stb.delStu(Integer.parseInt(sid));
		
		
		//判断
		if(n>0) {
			out.print(\"\");
		}
		else {
			System.out.println(\"检查dao方法\");
		}
		
	}

}

package com.cdl.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.cdl.biz.ClassBiz;
import com.cdl.biz.HobbyBiz;
import com.cdl.biz.IClassBiz;
import com.cdl.biz.IHobbyBiz;
import com.cdl.biz.IStuBiz;
import com.cdl.biz.ITeacBiz;
import com.cdl.biz.StuBiz;
import com.cdl.biz.TeaBiz;
import com.cdl.entity.Class;
import com.cdl.entity.Habby;
import com.cdl.entity.Student;
import com.cdl.entity.Teacher;

/**
 * 修改前的修改界面的绑值
 */
@WebServlet(\"/preupdate.do\")
public class PreUpdateServlet extends HttpServlet {
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}

	
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//设置编码方式
		request.setCharacterEncoding(\"utf-8\");
		response.setCharacterEncoding(\"utf-8\");
		response.setContentType(\"text/html; charset=UTF-8\");
		
		//获取out
		PrintWriter out = response.getWriter();
		
		//接收值
		String sid = request.getParameter(\"sid\");
		
		//调用biz层
		IStuBiz stb = new StuBiz();
		Student stu = stb.getStu(Integer.parseInt(sid));
		
		
		IHobbyBiz ihb = new HobbyBiz();
		
		IClassBiz icb = new ClassBiz();
		List clzall = icb.getAll();
		
		ITeacBiz itb = new TeaBiz();
		List teaall = itb.getAll();
		
		List hall = ihb.getAll();
		
		
		//实例化一个爱好的集合
		List ls = new ArrayList();
		String ss = stu.getSs();
		String[] split = ss.split(\",\");
		for (String string : split) {
			Habby hob = ihb.getHob(Integer.parseInt(string));
			//加进去
			ls.add(hob);
		}
		
		//将集合存起来
		request.setAttribute(\"clzall\", clzall);
		request.setAttribute(\"teaall\", teaall);
		request.setAttribute(\"ls\", ls);
		request.setAttribute(\"hall\", hall);
		request.setAttribute(\"stu\", stu);
		
		//+clzall+teaall+ls+hall
		//System.out.println(stu+\"=================\");
		
		//转发
		request.getRequestDispatcher(\"update.jsp\").forward(request, response);
		
		
	}
}

package com.cdl.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.cdl.biz.ClassBiz;
import com.cdl.biz.IClassBiz;
import com.cdl.biz.IStuBiz;
import com.cdl.biz.ITeacBiz;
import com.cdl.biz.StuBiz;
import com.cdl.biz.TeaBiz;
import com.cdl.entity.Class;
import com.cdl.entity.Student;
import com.cdl.entity.Teacher;

/**
 * 执行修改操作
 */
@WebServlet(\"/update.do\")
public class UpdateServlet extends HttpServlet {
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}

	
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//设置编码方式
		request.setCharacterEncoding(\"utf-8\");
		response.setCharacterEncoding(\"utf-8\");
		response.setContentType(\"text/html; charset=UTF-8\");
		
		//获取out
		PrintWriter out = response.getWriter();
		
		//接收值
		String sid = request.getParameter(\"sid\");
		String sname = request.getParameter(\"sname\");
		String tid = request.getParameter(\"tname\");
		String cid = request.getParameter(\"cname\");
		
		String [] id = request.getParameterValues(\"hname\");
		String hb = \"\";
		for (String string : id) {
			hb+=string;
		}
		
		//调用biz层
		ITeacBiz itb = new TeaBiz();
		Teacher tea = itb.getTea(Integer.valueOf(tid));
		
		IClassBiz icb = new ClassBiz();
		Class clz = icb.getClz(Integer.valueOf(cid));
		
		IStuBiz stb = new StuBiz();
		Student stu = new Student(Integer.parseInt(sid), sname, clz, tea, hb);
		int n = stb.upStu(stu, Integer.parseInt(sid));
		
		
		//判断
		if(n>0) {
			out.print(\"\");
		}
		else {
			System.out.println(\"检查dao方法\");
		}
		
	}


}

四、界面代码

index.jsp

<%@ page language=\"java\" contentType=\"text/html; charset=UTF-8\"
    pageEncoding=\"UTF-8\"%>
    
    <%@ taglib uri=\"http://java.sun.com/jsp/jstl/core\"  prefix=\"c\"%>




Insert title here





主界面

	

		
		
		
		
		
		
			
				
			
			爱好：
			
				${hobby.hname}
			
			
		

	




	
		
			
		
	
		
				

			

				学生的id
				学生的姓名
				学生的教员
				学生的所在班级
				学生的爱好
				操作
			

			
				
				

					${stu.sid}
					${stu.sname}
					${stu.tea.tname}
					${stu.c.cname}
					
						
							${h.hname}
						
					
					
						修改
						删除
					
					

				
		

		首页
		1?pageIndex-1:1}\">上一页
		[${pageIndex}/${max}]
		下一页
		尾页

运行效果

\"学生管理系统的增删改查_第6张图片\"

 

add.jsp

<%@ page language=\"java\" contentType=\"text/html; charset=UTF-8\"
    pageEncoding=\"UTF-8\"%>
     
    <%@ taglib uri=\"http://java.sun.com/jsp/jstl/core\"  prefix=\"c\"%>




Insert title here





新增页面

			                                        
	

	

		

			学号
			
		

		
		

			名字
			
		

		
		

			教员
			
				
			
		

		
		
		

			班级
			
				
			
		

		
		
		

			爱好
			
				
					
				
				
					${hobby.hname}

运行效果

\"学生管理系统的增删改查_第7张图片\"

update.jsp

<%@ page language=\"java\" contentType=\"text/html; charset=UTF-8\"
    pageEncoding=\"UTF-8\"%>
    
    <%@ taglib uri=\"http://java.sun.com/jsp/jstl/core\"  prefix=\"c\"%>




Insert title here





修改页面

			                                        
	

	

		
		

			学号
			
		

		
		

			名字
			
		

		
		

			教员
			
				
			
		

		
		
		

			班级
			
				
			
		

		
		
		

			爱好
			
				
					checked=\"checked\"/>${hobby.hname}

运行效果

\"学生管理系统的增删改查_第8张图片\"

 删除

\"学生管理系统的增删改查_第9张图片\"

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