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简易学生管理

2022-06-23 08:40:00 【安离九歌】

目录

一、 需求分析

二、数据库

三、实体类

四、mvc模式

五、界面

一、 需求分析

1）建表：

        需要建立四张表，班级表、学生表、教师表、爱好表

2）查询

可以多条件查询：根据班级、教师、爱好进行查询

3）新增

4）修改

修改要注意值得回显

5）分页

显示第几页，共几页，总记录多少条数据，可以选定页面跳转

6）删除

二、数据库

1）新建数据库以及表

        

2）添加值，以便测试

三、实体类

        1）根据数据库的表建立所需实体类

 班级叫Clazz为了防止与关键词Class重复

        2） 给实体类定义变量以及所需构造方法

例如：

package com.zhw.entity;

import java.util.List;

public class Student {
	private int sid;
	private String sname;
	private Clazz cid;
	private Teacher tid;
	private List<Hobby> hid;
	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 Clazz getCid() {
		return cid;
	}
	public void setCid(Clazz cid) {
		this.cid = cid;
	}
	public Teacher getTid() {
		return tid;
	}
	public void setTid(Teacher tid) {
		this.tid = tid;
	}
	public List<Hobby> getHid() {
		return hid;
	}
	public void setHid(List<Hobby> hid) {
		this.hid = hid;
	}
	
	public Student() {
		// TODO Auto-generated constructor stub
	}
	public Student(int sid, String sname, Clazz cid, Teacher tid, List<Hobby> hid) {
		super();
		this.sid = sid;
		this.sname = sname;
		this.cid = cid;
		this.tid = tid;
		this.hid = hid;
	}
	public Student(String sname, Clazz cid, Teacher tid, List<Hobby> hid) {
		super();
		this.sname = sname;
		this.cid = cid;
		this.tid = tid;
		this.hid = hid;
	}
	@Override
	public String toString() {
		return "Student [sid=" + sid + ", sname=" + sname + ", cid=" + cid + ", tid=" + tid + ", hid=" + hid + "]";
	}
	
}

 

四、mvc模式

1）定义数据库辅助类

package com.zhw.util;

import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
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");
	}
}

 

 2）定义功能所需的方法

例如： 

ClazzDaoImpl

package com.zhw.dao;

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

import com.zhw.entity.Clazz;
import com.zhw.entity.Hobby;
import com.zhw.util.DBHelper;

public class ClazzDaoImpl implements IClazzDao{

	Connection conn = null;
	Statement stmt = null;
	ResultSet rs = null;

	
	@Override
	public List<Clazz> getAll() {
		List<Clazz> ls = new ArrayList<Clazz>();
		try {
			conn = DBHelper.getConnection();
			String sql = "select * from tb_class";
			stmt = conn.prepareStatement(sql);
			rs = stmt.executeQuery(sql);
			while(rs.next()) {
				Clazz cl = new Clazz(rs.getInt(1),rs.getString(2));
				ls.add(cl);
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			DBHelper.close(conn, stmt, rs);
		}
		return ls;

	}


	@Override
	public Clazz getdg(int cid) {
		Clazz cl = new Clazz();
		try {
			conn = DBHelper.getConnection();
			String sql = "select * from tb_class where cid="+cid+"";
			stmt = conn.prepareStatement(sql);
			rs = stmt.executeQuery(sql);
			while(rs.next()) {
				cl = new Clazz(rs.getInt(1),rs.getString(2));
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			DBHelper.close(conn, stmt, rs);
		}
		return cl;

	}
	
	public static void main(String[] args) {
		System.out.println(new ClazzDaoImpl().getdg(1));
	}

}

IClazzDao

package com.zhw.dao;

import java.util.List;

import com.zhw.entity.Clazz;


public interface IClazzDao {

	public List<Clazz> getAll();
	
	public Clazz getdg(int cid);

}

IndexServlet

package com.zhw.servlet;

import java.io.IOException;
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.zhw.biz.ClazzBizImpl;
import com.zhw.biz.HyBizImpl;
import com.zhw.biz.IClazzBiz;
import com.zhw.biz.IHyBiz;
import com.zhw.biz.IStuBiz;
import com.zhw.biz.ITeacherBiz;
import com.zhw.biz.StuBizImpl;
import com.zhw.biz.TeacherBizImpl;
import com.zhw.entity.Clazz;
import com.zhw.entity.Hobby;
import com.zhw.entity.Student;
import com.zhw.entity.Teacher;


/**
 * Servlet implementation class IndexServlet
 */
@WebServlet("/IndexServlet")
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 {
	
		request.setCharacterEncoding("utf-8");
		response.setCharacterEncoding("utf-8");
		response.setContentType("text/html; charset=UTF-8");
		
		
		int pageIndex = 1;
		int pageSize = 2;
		
		String cid = request.getParameter("cid");
		if(cid==null) {
			cid="";
		}
		
		String tid= request.getParameter("tid");
		if(tid==null) {
			tid="";
		}
		String[] hids = request.getParameterValues("hid");
		String hid = "";
		String hidd ="";
		if(hids==null) {
			hidd=" ";
			hid="";
		}
		else {
			for (String str : hids) {
				hidd+=str+" ";
				hid= " where hid like '%"+hidd+"%' ";
			}
		}
		
		String pid = request.getParameter("pid");
		if(pid!=null){
			pageIndex = Integer.parseInt(pid);
		}
		
		String gid = request.getParameter("gid");
//		System.out.println("ska:"+gid);
		if(gid==null) {
			gid="";
		}
		else if(gid=="") {
			gid="";
		}
		else{
			pageIndex = Integer.parseInt(gid);
		}
		
		
		IStuBiz isb = new StuBizImpl();
		IHyBiz ihb = new HyBizImpl();
		ITeacherBiz itb = new TeacherBizImpl();
		IClazzBiz icb = new ClazzBizImpl();

		List<Student> stu = isb.getAll(cid, tid,hid, pageIndex, pageSize);
		List<Hobby> hobby1 = ihb.getAll();
		List<Teacher> teacher1 = itb.getAll();
		List<Clazz> clas1 = icb.getAll();
		int count = isb.count(cid, tid, hid);
		
		int pagecount=0;
		if(count%pageSize==1) {
			pagecount=count/pageSize+1;
		}
		else {
			pagecount=count/pageSize;
		}
		
		if(stu.size()!=0) {
			request.setAttribute("stu", stu);
			request.setAttribute("hobby1", hobby1);
			request.setAttribute("teacher1", teacher1);
			request.setAttribute("clas1", clas1);
			request.setAttribute("count", count);
			request.setAttribute("pagecount", pagecount);
			request.setAttribute("pageIndex", pageIndex);
			
			request.getRequestDispatcher("index.jsp").forward(request, response);
		}
		else {
			System.out.println("暂无数据");
		}
		
		
	}

}

五、界面

1）主界面

2）增加界面

 增加后结果

 

3）修改界面

修改后 

 

 4）删除

 

 删除后

 5）查询

 查询后

 

原网站

版权声明
本文为[安离九歌]所创，转载请带上原文链接，感谢
https://blog.csdn.net/qq_62331938/article/details/125372733

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