1 package Student_Manage;2 3 public class Student {4     public String name ;5     public int score ;6     public int code ;7 }

  1 package Student_Manage;  2 import javax.swing.JOptionPane;  3   4 public class Manage_UseClass {  5       6     public static Student [] student = new Student [20];//创建Student类的数组，用于存放学生  7     public static int number = 0;//学生数目  8       9     public static void main(String[] args) { 10         // 学生管理系统 11         //要求实现登陆，学生信息的添加、显示， 删除，修改，查询，排序，退出功能 12         /**欢迎光临界面*/ 13         JOptionPane.showMessageDialog(null, "欢迎光临！"); 14          15         /**登陆用户名、密码验证*/ 16         String user = "111" ; 17         String pwd = "222"; 18         for (int i = 0;i<3 ; i++){ 19             String in_user = JOptionPane.showInputDialog(null , "用户名："); 20             String in_pwd = JOptionPane.showInputDialog(null , "密码："); 21             if ( in_user.equals(user) && in_pwd.equals(pwd)){//判定用户名和密码是否正确 22                 break ; 23             }else { 24                 JOptionPane.showMessageDialog(null, "用户名或密码错误！"); 25                 if (i==2){ 26                     JOptionPane.showMessageDialog(null, "非法用户！"); 27                     System.exit(0); 28                 } 29             } 30         } 31          32         /**菜单选项*/ 33         while (true){ 34             int choose_num = Integer.parseInt(JOptionPane.showInputDialog(null , "1、添加\n2、显示\n3、删除\n4、修改\n5、查询\n6、排序\n7、退出")); 35             switch (choose_num){ 36                 case 1 :  37                     add() ;  38                     break ; 39                 case 2 :  40                     show();  41                     break ; 42                 case 3 :  43                     del() ;  44                     break ; 45                 case 4 :  46                     repair();  47                     break ; 48                 case 5 :  49                     check();  50                     break ; 51                 case 6 :  52                     sort();  53                     break ; 54                 case 7 :  55                     JOptionPane.showMessageDialog(null, "系统已退出！"); 56                     System.exit(0); 57                     break ; 58                 default : JOptionPane.showMessageDialog(null, "无此选项，请重新选择！");break ; 59             } 60         } 61     } 62     /**添加一个学生*/ 63     public static void add(){ 64         Student stu = new Student(); 65         stu.name = JOptionPane.showInputDialog(null,"请输入姓名："); 66         stu.code = Integer.parseInt(JOptionPane.showInputDialog(null, "请输入学号：")); 67         stu.score = Integer.parseInt(JOptionPane.showInputDialog(null, "请输入成绩：")); 68         student [number] = stu ; 69         number ++; 70     } 71      72     /**排序*/ 73     public static void sort() { 74         Student s = new Student() ; 75             for (int i =0;i < number ; i++){ 76                 for (int j = i; j<number;j++){ 77                     if(student [i].score < student [j].score){ 78                         s = student [i] ; 79                         student [i] = student [j] ; 80                         student [j] = s ; 81                     } 82                 } 83             } 84             JOptionPane.showMessageDialog(null, "排序成功！");     85     } 86     /**显示*/ 87     public static void show(){ 88         String s = "学号"+"    "+"姓名"+"    "+"成绩"+"\n"; 89         for (int i = 0 ;i< number ;i++){ 90             s+=student [i].code + "    "+ student [i].name+"    "+ student [i].score+"\n"; 91         } 92         JOptionPane.showMessageDialog(null, s); 93     } 94     /**删除*/ 95     public static void del(){ 96         int index = findByName(); 97         if (index != -1){ 98             //方法一：将最后位置的一个元素放在被删除元素的位置 99 //        name [index] = name[ number-1];100 //        card [index] =card[ number-1];101 //        score [index] = score[ number-1];102 //        number--;103             //方法二 ：连续将后一个元素填补至前一个元素104             for (int i = index; i <number  ; i++){105                 student [i] = student [i+1] ;106             }107             number--;108         JOptionPane.showMessageDialog(null, "删除成功！");    109         }110     }111     /**修改*/112     public static void repair(){113         int index = findByName();114         if (index !=-1){115             student[index].name  = JOptionPane.showInputDialog(null , "请输入新的名字：");116             student[index].code  = Integer.parseInt(JOptionPane.showInputDialog(null , "请输入该学生的学号"));117             student[index].score = Integer.parseInt(JOptionPane.showInputDialog(null , "请输入该学生的成绩"));118             JOptionPane.showMessageDialog(null, "修改成功！");119         }120     }121     /**查询*/122     public static void check(){123         int index  =findByName();124         if (index !=-1){125         JOptionPane.showMessageDialog(null,student[index].name+"\n学号：" +student[index].code+"\n成绩："+student[index].score);126         }127     }128     /**代码重用---查找*/129     public static int findByName (){130         int index = -1 ;131         String check_name = JOptionPane.showInputDialog(null,"请输入要查询的名字：");132         for (int i = 0; i< number ;i++){133             if (check_name.equals(student[i].name)){134                 return i ;135             }136         }137         if (index == -1){138             JOptionPane.showMessageDialog(null, "查无此人！");139         }140         return index ;141     }142 }