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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

在这里插入图片描述
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("\t\t\t+++++++++++++++++++++++");
		System.out.println("\t\t\t+ 0 退出 +");
		System.out.println("\t\t\t+ 1 录入成绩 +");
		System.out.println("\t\t\t+ 2 查询成绩 +");
		System.out.println("\t\t\t+ 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"+"\t"+"姓名"+"\t"+" 学号"+"\t\t"+"平均成绩");
while(rs.next()) { 

System.out.println(a+"\t"+rs.getString("name")+"\t"+rs.getString("num")+"\t\t"+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("\t\t"+"平均成绩"+"\t\t"+"最高成绩"+"\t\t"+"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： \t"+String.format("%.2f", sum)+"\t\t"+max+"\t\t"+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： \t"+String.format("%.2f", sum)+"\t\t"+max+"\t\t"+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)+"\t\t"+max+"\t\t"+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)+"\t\t"+max+"\t\t"+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"+"\t"+"姓 名"+"\t"+" 学 号"+"\t\t"+"平 均 成 绩"+"\n";
while(rs.next()) { 

s=s+"\n\n"+" "+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!");
	}
}