学生成绩管理系统

1.简介

本学生成绩管理系统具有录入学生成绩、查询学生成绩、输出学 生按成绩的排名、输出学科的分数四个功能，其中后两个功能在“输出成绩”这一目录下。 此系统可以实现学生成绩管理的一些基本操作。

1.1各模块功能简介

录入成绩

输入若干同学的学号、姓名以及四个科目的成绩（应用数学、大学英语、Java 程序设计、计算机应用基础），并将其保存在建立好的数据库中。

查询成绩

进入该模块后，输入想要查询成绩的学生姓名，即可在数据库中检索该学生 的成绩信息并输出其各科成绩。

输出成绩

该模块主要分为两部分，包括学生排名和各科目平均成绩及各科的最高分和 最低分。

（1）能够计算出平均成绩，以平均成绩降序输出成绩表。

（2）输出全组各科平均分，最高分和最低分。

2.程序设计

数据库表的设计

本系统将数据存储在一张表中，这张表名称为：students，能够保存学生的基本信息，包括学生的姓名、学号、应用数学成绩、大学英语成绩、Java 程序 设计成绩、计算机应用基础成绩、总成绩、平均成绩。

该表中 name 和 num 栏指 定的类型为 varchar 型，各科成绩的输入数据类型为 float 型。

建表时命令行输入为：

mysql> create table students(

-> name varchar(50) primary key,

-> num varchar(20),

-> math float(5,2),

-> English float(5,2),

-> Java float(5,2),

-> computer float(5,2),

-> score float(5,2),

-> average float(5,2)

-> );

3.源代码

package kechengsheji;
import kechengsheji.Outnum;
import java.util.Scanner;
import kechengsheji.*;
public class Main {
	public Main() {
		Scanner in=new Scanner(System.in);
		int a=4;    //a不等于0，进入循环
		while(a!=0) {
		System.out.println("			+++++++++++++++++++++++");
		System.out.println("			+     0 退出                      +");
		System.out.println("			+     1 录入成绩               +");
		System.out.println("			+     2 查询成绩               +");
		System.out.println("			+     3 输出成绩               +");
		System.out.println("请输入0-3：");
		a=in.nextInt();
		switch(a) {
			case 0:
				System.out.println("退出成功！");
				break;
			case 1:
				new Input();
				break;
			case 2: 
				new Seeknum();
				break;
			case 3:
				new Outnum(); 
				break;
			default:
				System.out.println("输入有误！");
				break;
			}
		}
	}
	
	public static void main(String[] args) {
		new Main();
	}
}
package kechengsheji;
import java.sql.*;
public class SQL {
	Connection conn;
	public Connection getConn() {
		 try {
			 Class.forName("com.mysql.cj.jdbc.Driver");
	                
	            String url="jdbc:mysql://localhost:3306/swy"
		        		+ "?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8&useSSL=false";    //JDBC的URL    
	            conn = DriverManager.getConnection(url, "root","266531"); //建立数据库连接，获得连接对象conn
		 }catch(ClassNotFoundException e){
			 e.printStackTrace();
		 }catch (SQLException e) {
			e.printStackTrace();
		}
		return conn;
	}
	public static void main(String[] args) {
		System.out.println("hello world!");
	}
}
package kechengsheji;
import java.util.Scanner;
import java.sql.*;
import kechengsheji.SQL;
public class Input {
	private String b,c;
	private double d,e,f,g;
	private double sum,aver;
	Scanner in=new Scanner(System.in);
	private int a=2; 
	Input(){
		while(a!=0) {
			System.out.println("+++++++++++++++++++++");
			System.out.println("+    1 录入成绩     +");
			System.out.println("+    0 返回         +");
			a=in.nextInt();
			switch (a) {                                  
            case 0:
                 System.out.println("返回成功！");
                 break;
            case 1:
            	System.out.println("请输入学生姓名：");
            	b=in.next();
            	System.out.println("请输入学生学号：");
            	c=in.next();
            	System.out.println("请输入学生应用数学成绩：");
            	d=in.nextDouble();
            	System.out.println("请输入学生大学英语成绩：");
            	e=in.nextDouble();
            	System.out.println("请输入学生Java程序设计成绩：");
            	f=in.nextDouble();
            	System.out.println("请输入学生计算机应用基础成绩：");
            	g=in.nextDouble();
            	sum=d+e+f+g;   //总成绩
            	aver=sum/4;    //平均成绩
            	//数据库
            	SQL bd=new SQL();
    			Connection conn=bd.getConn();
            	try {
            	Statement stmt = conn.createStatement(); //创建Statement对象
            	try {
                String sql = "insert into students values(?,?,?,?,?,?,?,?)"; //要执行的SQL
                PreparedStatement pst = conn.prepareStatement(sql);
                pst.setString(1,b);                             //传入带占位符的SQL语句
        		pst.setString(2,c);
        		pst.setDouble(3,d);
        		pst.setDouble(4,e);
        		pst.setDouble(5,f);
        		pst.setDouble(6,g);
        		pst.setDouble(7,sum);
        		pst.setDouble(8,aver);
        		pst.executeUpdate(); //执行 update和insert、delete等sql语句
        		System.out.println("保存成功！");
        		pst.close();
            	}catch(SQLIntegrityConstraintViolationException e) {
            		System.out.println("该学生已存在！");
            	}
                stmt.close();
                conn.close();
            	}catch(SQLException e){
            		e.printStackTrace();
            	}
            	//数据库
            	break;
            default:
            	System.out.println("输入错误！");
			}
		}
	}
	public static void main(String[] args) {
		new Input();
	}
}
package kechengsheji;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Scanner;
import kechengsheji.SQL;;
public class Seeknum {
	private String num,nam;
	int i=0;
	Seeknum(){
		   Scanner s1 =new Scanner(System.in);
	       int a = 3;
	       while(a!=0){
	        	 System.out.println("*********************");//查找界面并选择
	        	 System.out.println("*    0 返回         *");
	        	 System.out.println("*   1 查询成绩      *");
	        	 System.out.println("请输入0或1：");
	        	 a =s1.nextInt();
	       switch (a) {                                  
	             case 0:
	                  System.out.println("返回成功！");
	                  break;
	             case 1:
	            	 //数据库
	            		SQL bd=new SQL();
	            		Connection conn=bd.getConn(); 
	            	 try {
	                  System.out.println("请输入姓名：");
	                  nam=s1.next();
	                  Statement stmt = conn.createStatement(); //创建Statement对象
	                  String sql = "select * from students;";    //要执行的SQL
	                  ResultSet rs = stmt.executeQuery(sql);//创建数据对象，产生单个结果集的语句
	                  while(rs.next()) {
	                	  if(rs.getString("name").equals(nam)) {
	                		  i=1;
	                			System.out.println("成绩如下:");
	      	    	          //从数据库查找成绩
	      	                  System.out.println();
	      	    	          System.out.println("姓名："+rs.getString(1) );
	      	    	          System.out.println("学号：" +rs.getString(2) );
	      	    	          System.out.println("应用数学：" +rs.getDouble(3) );
	      	    	          System.out.println("大学英语 ：" +rs.getDouble(4) );
	      	    	          System.out.println("java程序设计：" +rs.getDouble(5) );
	      	    	          System.out.println("计算机应用基础：" +rs.getDouble(6) );
	      	    	          System.out.println("总分：" +rs.getDouble(7) );
	      	    	          System.out.println("平均分：" +rs.getDouble(8) ); 
	      	    	          System.out.println();
	      	    	          //数据库
	      	    	          break;
	                	  }
	                		  
	                  }
	    	          if(i==0)
		                  System.out.println("暂无该学生成绩！");
	    	          rs.close();
	                  stmt.close();
	                  conn.close();
	            	 }catch (SQLException e) {
	            		 e.printStackTrace();
					}
	             break;
	             default:
	             System.out.println("输入有误！");
	             break;
	         }
	 }
}
    public static void main(String[] args){    
         new Seeknum();
         }
    	
}
package kechengsheji;
import kechengsheji.paiming;
import kechengsheji.kemuchengji;
import java.util.Scanner;
import java.sql.*;
public class Outnum {
	Scanner in=new Scanner(System.in);
	private int a=3;
	Outnum(){
		while(a!=0){
			System.out.println("+++++++++++++++++++");
			System.out.println("+  1 排名         +");
			System.out.println("+  2 科目成绩     +");
			System.out.println("+  0 返回         +");
			System.out.println("请输入0-2：");
			a=in.nextInt();
			switch(a) {
			case 0:
				System.out.println("返回成功！");
				System.out.println();
				break;
			case 1:
				new paiming();
				break;
			case 2:
				new kemuchengji();
				break;
			default:
				System.out.println("输入有误！");
			}
			
		}
	}
	public static void main(String[] args) {
		new Outnum();
	}
}
package kechengsheji;
import java.sql.*;
public class paiming {
	SQL bd=new SQL();
	Connection conn=bd.getConn(); 
	private int a=1;
	paiming(){
        try {
        	//数据库
        	Statement stmt;
        	stmt = conn.createStatement();
        	String sql="select name,num,average from students order by average desc;";
        	ResultSet rs = stmt.executeQuery(sql);
        	System.out.println();
        	System.out.println("排名"+"	"+"姓名"+"	"+"  学号"+"		"+"平均成绩");
        	while(rs.next()) {
        	System.out.println(a+"	"+rs.getString("name")+"	"+rs.getString("num")+"		"+rs.getDouble("average"));	
        	a++;
        	}
        	rs.close();
        	stmt.close();
            conn.close();
        }catch(Exception e){
        	e.printStackTrace();
        }
        
	}
	public static void main(String[] args) {
		new paiming();
	}
}
package kechengsheji;
import java.sql.*;
import kechengsheji.SQL;
public class kemuchengji {
	private double sum,max,min;
	SQL bd=new SQL();
	Connection conn=bd.getConn(); 
	kemuchengji(){
		System.out.println();
		System.out.println("		"+"平均成绩"+"		"+"最高成绩"+"		"+"最低成绩");
		try {
		Statement stmt = conn.createStatement(); //创建Statement对象
		int i=0;
		String sql = "select math from students order by math desc;";    //要执行的SQL
        ResultSet rs = stmt.executeQuery(sql);
        while(rs.next()) {
        	sum=sum+rs.getDouble("math");
        	i++;
        	if(rs.isFirst())
        		max=rs.getDouble("math");
        	if(rs.isLast())
        		min=rs.getDouble("math");
        }
        sum=sum/i;//平均成绩
        System.out.println("应用数学成绩：      	"+String.format("%.2f", sum)+"		"+max+"		"+min);
        
        i=0;
        sum=0.0;
		String sql1 = "select English from students order by English desc;";    //要执行的SQL
        ResultSet rs1 = stmt.executeQuery(sql1);
        while(rs1.next()) {
        	sum=sum+rs1.getDouble("English");
        	i++;
        	if(rs1.isFirst())
        		max=rs1.getDouble("English");
        	if(rs1.isLast())
        		min=rs1.getDouble("English");
        }
        sum=sum/i; //平均成绩
        System.out.println("大学英语成绩：     	"+String.format("%.2f", sum)+"		"+max+"		"+min);
        
        i=0;
        sum=0.0;
        //数据库
		String sql2 = "select Java from students order by Java desc;";    //要执行的SQL
        ResultSet rs2 = stmt.executeQuery(sql2);
        while(rs2.next()) {
        	sum=sum+rs2.getDouble("Java");
        	i++;
        	if(rs2.isFirst())
        		max=rs2.getDouble("Java");
        	if(rs2.isLast())
        		min=rs2.getDouble("Java");
        }
        sum=sum/i;//平均成绩
        System.out.println("Java程序设计成绩：  "+String.format("%.2f", sum)+"		"+max+"		"+min);
        
        i=0;
        sum=0.0;
		String sql3 = "select computer from students order by computer desc;";    //要执行的SQL
        ResultSet rs3 = stmt.executeQuery(sql3);
        while(rs3.next()) {
        	sum=sum+rs3.getDouble("computer");
        	i++;
        	if(rs3.isFirst())
        		max=rs3.getDouble("computer");
        	if(rs3.isLast())
        		min=rs3.getDouble("computer");
        }
        sum=sum/i;                //平均成绩
        System.out.println("计算机应用基础成绩："+String.format("%.2f", sum)+"		"+max+"		"+min);
        System.out.println();
        
        rs.close();
        rs1.close();
        rs2.close();
        rs3.close();
        stmt.close();
        conn.close();
		}catch(SQLException e) {
			e.printStackTrace();
		}
	}
	public static void main(String[] args) {
		new kemuchengji();
	}
}

4.结果展示

5.采用GUI界面

源代码

package kechengsheji;
import java.awt.*;
import java.awt.event.*;
import javax.sql.rowset.serial.SerialArray;
public class GUImain extends Frame implements ActionListener{
	private Button b1,b2,b3,b4;
	private Label a1,a2;
	private GridBagLayout gb;
	private GridBagConstraints gbc;
	private GUImain(){
		a1=new Label("     欢迎使用学生成绩管理系统");
		a1.setFont(new Font(null,Font.LAYOUT_RIGHT_TO_LEFT,20));
		a2=new Label("                     ");
		gb=new GridBagLayout(); //初始化 gb 
		setLayout(gb); //设置窗口布局管理器 gb 
		gbc=new GridBagConstraints(); //初始化网格包容器
		b1=new Button("输入成绩"); //初始化按钮 btn1 
		b2=new Button("查询成绩"); 
		b3=new Button("输出成绩");
		b4=new Button("退出系统");
	    b1.addActionListener(this);
		b2.addActionListener(this);
	    b3.addActionListener(this);
		b4.addActionListener(this);
		 addWindowListener(new WindowAdapter(){ 
			 public void windowClosing(WindowEvent e){
		     setVisible(false);
		     dispose();
			 System.exit(0); //程序退出
			 } 
			 }); 	 
		 gbc.fill=GridBagConstraints.HORIZONTAL; //设置 gbc 的 fill 域
		 addComponent(a1,0, 2, 1, 4);
		 addComponent(a2,4, 2, 1, 2);
		 addComponent(b1,6, 2, 1, 2);
		 addComponent(b2,8, 2, 1, 2);
		 addComponent(b3,10, 2, 1, 2); 
		 addComponent(b4,12, 2, 1, 2);
	}
	public void actionPerformed(ActionEvent e) {
		if(e.getActionCommand()=="输入成绩") {
			GUIinput mygb =new GUIinput(); 
			 mygb.setSize(600,400);
			 mygb.setVisible(true);
		}else if(e.getActionCommand()=="查询成绩") {
			GUISeeknum mygb =new GUISeeknum(); 
			 mygb.setSize(600,400);
			 mygb.setVisible(true);
		}else if(e.getActionCommand()=="输出成绩") {
			GUIOutnum mygb=new GUIOutnum();
			 mygb.setSize(700,500);
			 mygb.setVisible(true);
		}else if(e.getActionCommand()=="退出系统") {
		     setVisible(false);
		     dispose();
			 System.exit(0); 
		}
	}	
	 public void addComponent(Component c,int row,int col, int nrow,int ncol){ 
	 gbc.gridx=col; //设置组件显示区域的开始边单元格
	 gbc.gridy=row; //设置组件显示区域的顶端单元格
	 gbc.gridheight=ncol; //设置组件显示区域一列的单元格数
	 gbc.gridwidth=nrow; //设置组件显示区域一行的单元格数
	 gb.setConstraints(c,gbc); //设置布局的约束条件
	 add(c); //组件 c 添加到容器中
  }
	public static void main(String[] args) {
		GUImain mygb =new GUImain(); 
		 mygb.setSize(700,500);
		 mygb.setVisible(true);
	}
}
package kechengsheji;
import java.awt.*;
import java.awt.event.*;
import java.util.Scanner;
import java.sql.*;
import kechengsheji.SQL;
public class GUIinput extends Frame implements ActionListener{
	Frame my;
	private int a=0;
	private Label l1,l2,l3,l4,l5,l6;
	private TextField tf1,tf2,tf3,tf4,tf5,tf6;
	private Button btn1,btn2,b1;
	private GridBagLayout gb;
	private GridBagConstraints gbc;
	private String a1,a2;
	private double a3,a4,a5,a6,sum,aver;
	public GUIinput() {
		l1=new Label("姓名                   ");
		l2=new Label("学号                   ");
		l3=new Label("应用数学           ");
		l4=new Label("大学英语           ");
		l5=new Label("Java程序设计   ");
		l6=new Label("计算机应用基础");
		tf1=new TextField(20);
		tf2=new TextField(20);
		tf3=new TextField(20);
		tf4=new TextField(20);
		tf5=new TextField(20);
		tf6=new TextField(20);
		gb=new GridBagLayout(); //初始化 gb 
		 setLayout(gb); //设置窗口布局管理器 gb 
		 gbc=new GridBagConstraints(); //初始化网格包容器
		 btn1=new Button("提交"); //初始化按钮 btn1 
		 btn2=new Button("退出"); 
		 btn1.addActionListener(this);
		 btn2.addActionListener(this);
		 
		 Panel p0 = new Panel(); //创建，并初始化面板 p1 
		 p0.add(btn1); 
		 p0.add(btn2);
		 Panel p1 = new Panel();
		 p1.add(l1);
		 p1.add(tf1);
		 Panel p2 = new Panel();
		 p2.add(l2);
		 p2.add(tf2);
		 Panel p3 = new Panel();
		 p3.add(l3);
		 p3.add(tf3);
		 Panel p4 = new Panel();
		 p4.add(l4);
		 p4.add(tf4);
		 Panel p5 = new Panel();
		 p5.add(l5);
		 p5.add(tf5);
		 Panel p6 = new Panel();
		 p6.add(l6);
		 p6.add(tf6);
		 
		 addWindowListener(new WindowAdapter(){ 
			 public void windowClosing(WindowEvent e){
		     setVisible(false);
		     dispose();
			 System.exit(0); //程序退出
			 } 
			 }); 
		 
			 gbc.fill=GridBagConstraints.HORIZONTAL; //设置 gbc 的 fill 域
			 
			 addComponent(p1,0, 2, 1, 1);
			 addComponent(p2,2, 2, 1, 1);
			 addComponent(p3,3, 2, 1, 1);
			 addComponent(p4,4, 2, 1, 1); 
			 addComponent(p5,5, 2, 1, 1);
			 addComponent(p6,6, 2, 1, 1);
			 addComponent(p0,9, 2, 1, 1); 
			 }
//********************************************************************************8
	public void gui() {
		 my=new Frame();
		 my.setBounds(300,300,350,250);
		 my.setLayout(null);
		 my.setVisible(true); 
		 b1=new Button("返回");
		 b1.addActionListener(this);
		Label a1=new Label("该学生已存在！ ");
		Label a2=new Label("添加成功！");
		Label a3=new Label("输入为空！");
		 if(a==1) {
			 my.add(a1);
		 a1.setBounds(140,100,100,40);
		 }
		 else if(a==0) {
			 my.add(a2);
		 	 a2.setBounds(140,100,100,40);
		 }
		 else if(a==2) {
			 my.add(a3);
			 a3.setBounds(140,100,100,40);
		 }
		 my.add(b1); 
		 b1.setBounds(230,190,80,30);
		my.addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent evt) {
				my.setVisible(false);
				my.dispose();
				}
			});
	}
//******************************************************************************************************
	public void actionPerformed(ActionEvent e) {
		if(e.getSource()==btn1) {
		a1=tf1.getText();
    	if(a1.equals(""))
    		a=2;
    	else {
    	a=0;
		a2=tf2.getText();
		a3=Double.parseDouble(tf3.getText() );
		a4=Double.parseDouble(tf4.getText() );
		a5=Double.parseDouble(tf5.getText() );
		a6=Double.parseDouble(tf5.getText() );
    	sum=a3+a4+a5+a6;   //总成绩
    	aver=sum/4;    //平均成绩
    	
    	SQL bd=new SQL();
		Connection conn=bd.getConn();
    	try {
    	Statement stmt = conn.createStatement(); //创建Statement对象
    	try {
        String sql = "insert into students values(?,?,?,?,?,?,?,?)"; //要执行的SQL
        PreparedStatement pst = conn.prepareStatement(sql);
        pst.setString(1,a1);                             //传入带占位符的SQL语句
		pst.setString(2,a2);
		pst.setDouble(3,a3);
		pst.setDouble(4,a4);
		pst.setDouble(5,a5);
		pst.setDouble(6,a6);
		pst.setDouble(7,sum);
		pst.setDouble(8,aver);
		pst.executeUpdate(); //执行 update和insert、delete等sql语句
		pst.close();
    	}catch(SQLIntegrityConstraintViolationException e1) {
    		a=1;
    	}
        stmt.close();
        conn.close();
    	}catch(SQLException e2){
    		e2.printStackTrace();
    	}
    	}
    	gui();
		}else if(e.getSource()==btn2) {
			setVisible(false);
			dispose();
		}else if(e.getSource()==b1) {
			my.setVisible(false);
			my.dispose();
		}
		
	}
//*******************************************************************************************
			 public void addComponent(Component c,int row,int col, int nrow,int ncol){ 
			 gbc.gridx=col; //设置组件显示区域的开始边单元格
			 gbc.gridy=row; //设置组件显示区域的顶端单元格
			 gbc.gridheight=ncol; //设置组件显示区域一列的单元格数
			 gbc.gridwidth=nrow; //设置组件显示区域一行的单元格数
			 gb.setConstraints(c,gbc); //设置布局的约束条件
			 add(c); //组件 c 添加到容器中
	        }
//******************************入口***********************************************************			 
	public static void main(String[] args) {
		GUIinput mygb =new GUIinput(); 
		 mygb.setSize(600,400);
		 mygb.setVisible(true);
	}
}
package kechengsheji;
import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import kechengsheji.SQL;
public class GUISeeknum extends Frame implements ActionListener{
	Frame my;
	String b;
	private Label a1;
	private Button b1,b2;
	private TextField c1;
	private GridBagLayout gb;
	private GridBagConstraints gbc;
	public GUISeeknum() {
		a1=new Label("请输入学生姓名： ");
		c1=new TextField(20);
		gb=new GridBagLayout(); //初始化 gb 
		setLayout(gb); //设置窗口布局管理器 gb 
		gbc=new GridBagConstraints(); //初始化网格包容器
		b1=new Button("查询"); //初始化按钮 btn1 
		b2=new Button("退出"); 
	    b1.addActionListener(this);
		b2.addActionListener(this);
		 Panel p0 = new Panel(); //创建，并初始化面板 p1 
		 p0.add(a1); 
		 p0.add(c1);
		 Panel p1 = new Panel();
		 p1.add(b1);
		 p1.add(b2);
		 
		 addWindowListener(new WindowAdapter(){ 
			 public void windowClosing(WindowEvent e){
		     setVisible(false);
		     dispose();
			 System.exit(0); //程序退出
			 } 
			 }); 
		 
		 gbc.fill=GridBagConstraints.HORIZONTAL; //设置 gbc 的 fill 域
		 addComponent(p0,0, 2, 1, 2);
		 addComponent(p1,4, 2, 1, 1);
	}
	
	public void actionPerformed(ActionEvent e) {
		if(e.getActionCommand()=="查询") {
			b=c1.getText();
			gui1(b);
		}else if(e.getActionCommand()=="退出") {
		     setVisible(false);
		     dispose();
		}else if(e.getActionCommand()=="返回") {
			 my.setVisible(false);
		     my.dispose();
		}
	}
	
	public void gui1(String n) {
		Label a0,a1,a2,a3,a4,a5,a6,a7,a8;
		my=new Frame();
		my.setBounds(300,300,450,450);
		my.setLayout(null);
		my.setVisible(true); 
		Button b1=new Button("返回");
		b1.addActionListener(this);
		a0=new Label("该学生不存在！ ");
		int a=0;
		SQL bd=new SQL();
		Connection conn=bd.getConn(); 
		try {
            Statement stmt = conn.createStatement(); //创建Statement对象
            String sql = "select * from students;";    //要执行的SQL
            ResultSet rs = stmt.executeQuery(sql);//创建数据对象，产生单个结果集的语句
            while(rs.next()) {
          	  if(rs.getString("name").equals(n)) {
          		  a=1;//有成绩
	    	          //从数据库查找成绩
          		a1=new Label("姓名："+rs.getString(1));
          		a2=new Label("学号："+rs.getString(2));
          		a3=new Label("应用数学：" +rs.getDouble(3));
          		a4=new Label("大学英语 ：" +rs.getDouble(4));
          		a5=new Label("java程序设计：" +rs.getDouble(5));
          		a6=new Label("计算机应用基础：" +rs.getDouble(6));
          		a7=new Label("总分：" +rs.getDouble(7));
          		a8=new Label("平均分：" +rs.getDouble(8));
	        	  my.add(a1);
	        	  my.add(a2);
	        	  my.add(a3);
	        	  my.add(a4);
	        	  my.add(a5);
	        	  my.add(a6);
	        	  my.add(a7);
	        	  my.add(a8);
			        a1.setBounds(70,20,300,60);// 距左边的距离   距顶部的距离   长度  高度
			 		a2.setBounds(70, 70,300,50);
			 		a3.setBounds(70, 110, 300,50);
			 		a4.setBounds(70, 150, 300,50);
			 		a5.setBounds(70, 190, 300,50);
			 		a6.setBounds(70, 230, 300,50);
			 		a7.setBounds(70, 270, 300,50);
			 		a8.setBounds(70, 310, 300,50);
	        	  
	    	          //数据库
	    	          break;
          	  }  
            }
	          if(a==0) {
	      		my.add(a0);
	      		a0.setBounds(170,180,300,60);
	          }
	 		 my.add(b1); 
	 		 	b1.setBounds(300, 360, 100,40);
	 		my.addWindowListener(new WindowAdapter() {
	 			public void windowClosing(WindowEvent evt) {
	 				my.setVisible(false);
	 				my.dispose();
	 				}
	 			});
	          rs.close();
            stmt.close();
            conn.close();
      	 }catch (SQLException e) {
      		 e.printStackTrace();
			}
	}
	
	 public void addComponent(Component c,int row,int col, int nrow,int ncol){ 
	 gbc.gridx=col; //设置组件显示区域的开始边单元格
	 gbc.gridy=row; //设置组件显示区域的顶端单元格
	 gbc.gridheight=ncol; //设置组件显示区域一列的单元格数
	 gbc.gridwidth=nrow; //设置组件显示区域一行的单元格数
	 gb.setConstraints(c,gbc); //设置布局的约束条件
	 add(c); //组件 c 添加到容器中
   }
	 
	public static void main(String[] args) {
		GUISeeknum mygb =new GUISeeknum(); 
		 mygb.setSize(600,400);
		 mygb.setVisible(true);
	}
}
package kechengsheji;
import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import kechengsheji.SQL;
public class GUIOutnum extends Frame implements ActionListener{
	private double sum,max,min;
	private String s;
	private TextArea m1;
	Frame c1,c2;
	private Button b1,b2,b3,b4,b5;
	private GridBagLayout gb;
	private GridBagConstraints gbc;
	public GUIOutnum() {
		gb=new GridBagLayout(); //初始化 gb 
		 setLayout(gb); //设置窗口布局管理器 gb 
		 gbc=new GridBagConstraints(); //初始化网格包容器
		 b1=new Button("               总体排名                "); //初始化按钮 btn1 
		 b2=new Button("      科目成绩        "); 
		 b3=new Button("        返回         ");
		 b1.addActionListener(this);
		 b2.addActionListener(this);
		 b3.addActionListener(this);
		 addWindowListener(new WindowAdapter(){ 
			 public void windowClosing(WindowEvent e){
		     setVisible(false);
		     dispose();
			 System.exit(0); //程序退出
			 } 
			 }); 
			 gbc.fill=GridBagConstraints.HORIZONTAL;//设置 gbc 的 fill 域horizontal
			 addComponent(b1,0, 2, 1, 2);
			 addComponent(b2,2, 2, 1, 2);
			 addComponent(b3,4, 2, 1, 2);
	}
	
	 public void addComponent(Component c,int row,int col, int nrow,int ncol){ 
	 gbc.gridx=col; //设置组件显示区域的开始边单元格
	 gbc.gridy=row; //设置组件显示区域的顶端单元格
	 gbc.gridheight=ncol; //设置组件显示区域一列的单元格数
	 gbc.gridwidth=nrow; //设置组件显示区域一行的单元格数
	 gb.setConstraints(c,gbc); //设置布局的约束条件
	 add(c); //组件 c 添加到容器中
   }
	 
		public void actionPerformed(ActionEvent e) {
			if(e.getSource()==b1) {
				//*********总体排名**********
				c2=new Frame();
				c2.setBounds(600,130,500,750);
				c2.setLayout(null);
				c2.setVisible(true); 
				b5=new Button("返回");
				b5.addActionListener(this);
		 		c2.addWindowListener(new WindowAdapter() {
		 			public void windowClosing(WindowEvent evt) {
		 				c2.setVisible(false);
		 				c2.dispose();
		 				}
		 			});
		 		
				
				SQL bd=new SQL();
				Connection conn=bd.getConn(); 
				int a=1;
			       try {
			        	//数据库
			        	Statement stmt;
			        	stmt = conn.createStatement();
			        	String sql="select name,num,average from students order by average desc;";
			        	ResultSet rs = stmt.executeQuery(sql);
			        	s="排 名"+"	"+"姓 名"+"	"+"  学 号"+"		"+"平 均 成 绩"+"
";
			        	while(rs.next()) {
			        	s=s+"
"+" "+a+"        "+rs.getString("name")+"        "+rs.getString("num")+"                "+rs.getDouble("average");	
			        	a++;
			        	}
			        	m1=new TextArea(s);
			        	m1.setEditable(false);
			        	m1.setBounds(50,50,400,550);
			        	c2.add(m1);
			        	b5.setBounds(380,690,80,30);
			        	c2.add(b5);
			        	
			        	rs.close();
			        	stmt.close();
			            conn.close();
			        }catch(Exception e1){
			        	e1.printStackTrace();
			        }
			       
			}else if(e.getSource()==b2) {
				//********科目成绩***********
				c1=new Frame();
				c1.setBounds(300,300,450,450);
				c1.setLayout(null);
				c1.setVisible(true);
				Label a1,a2,a3,a4,a5;
				a1=new Label("                  平均成绩      最高成绩       最低成绩");
				b4=new Button("返回");
				b4.addActionListener(this);
		 		c1.addWindowListener(new WindowAdapter() {
		 			public void windowClosing(WindowEvent evt) {
		 				c1.setVisible(false);
		 				c1.dispose();
		 				}
		 			});
				SQL bd=new SQL();
				Connection conn=bd.getConn(); 
				try {
					Statement stmt = conn.createStatement(); //创建Statement对象
					int i=0;
					String sql = "select math from students order by math desc;";    //要执行的SQL
			        ResultSet rs = stmt.executeQuery(sql);
			        while(rs.next()) {
			        	sum=sum+rs.getDouble("math");
			        	i++;
			        	if(rs.isFirst())
			        		max=rs.getDouble("math");
			        	if(rs.isLast())
			        		min=rs.getDouble("math");
			        }
			        sum=sum/i;//平均成绩
			        a2=new Label("应用数学成绩：           "+String.format("%.2f", sum)+"              "+max+"                "+min);
			        
			        i=0;
			        sum=0.0;
					String sql1 = "select English from students order by English desc;";    //要执行的SQL
			        ResultSet rs1 = stmt.executeQuery(sql1);
			        while(rs1.next()) {
			        	sum=sum+rs1.getDouble("English");
			        	i++;
			        	if(rs1.isFirst())
			        		max=rs1.getDouble("English");
			        	if(rs1.isLast())
			        		min=rs1.getDouble("English");
			        }
			        sum=sum/i; //平均成绩
			        a3=new Label("大学英语成绩：           "+String.format("%.2f", sum)+"            "+max+"               "+min);
			        
			        i=0;
			        sum=0.0;
			        //数据库
					String sql2 = "select Java from students order by Java desc;";    //要执行的SQL
			        ResultSet rs2 = stmt.executeQuery(sql2);
			        while(rs2.next()) {
			        	sum=sum+rs2.getDouble("Java");
			        	i++;
			        	if(rs2.isFirst())
			        		max=rs2.getDouble("Java");
			        	if(rs2.isLast())
			        		min=rs2.getDouble("Java");
			        }
			        sum=sum/i;//平均成绩
			       a4=new Label("Java程序设计成绩：   "+String.format("%.2f", sum)+"            "+max+"                "+min);
			        
			        i=0;
			        sum=0.0;
					String sql3 = "select computer from students order by computer desc;";    //要执行的SQL
			        ResultSet rs3 = stmt.executeQuery(sql3);
			        while(rs3.next()) {
			        	sum=sum+rs3.getDouble("computer");
			        	i++;
			        	if(rs3.isFirst())
			        		max=rs3.getDouble("computer");
			        	if(rs3.isLast())
			        		min=rs3.getDouble("computer");
			        }
			        sum=sum/i;                //平均成绩
			        a5=new Label("计算机应用基础成绩：  "+String.format("%.2f", sum)+"          "+max+"                "+min);
			        
			        a1.setBounds(70,20,300,60);// 距左边的距离   距顶部的距离   长度  高度
			 		a2.setBounds(10, 70,300,50);
			 		a3.setBounds(10, 110, 300,50);
			 		a4.setBounds(10, 150, 300,50);
			 		a5.setBounds(10, 190, 300,50);
			 		b4.setBounds(300, 360, 100,40);
			 		 c1.add(a1);
			 		 c1.add(a2);
			 		 c1.add(a3);
			 		 c1.add(a4);
			 		 c1.add(a5);
			 		 c1.add(b4);
			 		
			        rs.close();
			        rs1.close();
			        rs2.close();
			        rs3.close();
			        stmt.close();
			        conn.close();
					}catch(SQLException e1) {
						e1.printStackTrace();
					}				
				
			}else if(e.getSource()==b3) {
				setVisible(false);
				dispose();
			}else if(e.getSource()==b4) {
				c1.setVisible(false);
				c1.dispose();
			}else if(e.getSource()==b5) {
				c2.setVisible(false);
				c2.dispose();
			}
		}		
	public static void main(String[] args) {
		GUIOutnum mygb=new GUIOutnum();
		 mygb.setSize(700,500);
		 mygb.setVisible(true);
	}
}
package kechengsheji;
import java.sql.*;
public class SQL {
	Connection conn;
	public Connection getConn() {
		 try {
			 Class.forName("com.mysql.cj.jdbc.Driver");
	                
	            String url="jdbc:mysql://localhost:3306/swy"
		        		+ "?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8&useSSL=false";    //JDBC的URL    
	            conn = DriverManager.getConnection(url, "root","266531"); //建立数据库连接，获得连接对象conn
		 }catch(ClassNotFoundException e){
			 e.printStackTrace();
		 }catch (SQLException e) {
			e.printStackTrace();
		}
		return conn;
	}
	public static void main(String[] args) {
		System.out.println("hello world!");
	}
}

6.结果展示

附上源码的下载链接，由于本人是初学者，此系统是我做的课程设计，由于时间比较仓促，水平有限，仅供大家参考学习。

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源码下载链接