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); }//********************************************************************************8public 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
来源地址:https://blog.csdn.net/m0_67402236/article/details/125401535