java学生信息管理Arraylist的运用

  1 import java.io.File;
  2 import java.io.FileNotFoundException;
  3 import java.io.PrintStream;
  4 import java.util.ArrayList;
  5 import java.util.Iterator;
  6 import java.util.Scanner;
  7  
  8 public class Windzly {
  9     
 10     static ArrayList<Student> list = new ArrayList<Student>();
 11     
 12     public static void main(String[] arg) throws FileNotFoundException {
 13         Scanner sc = new Scanner(System.in);
 14         
 15         readfile();//读取文本文件
 16         
 17         
 18         int n;
 19         while(true)
 20         {
 21             System.out.println("1、添加学生    2、删除指定学号的学生    3、修改指定学号的成绩   "
 22                     + " 4、查找指定学号的信息    5、打印所有的学生信息    6、退出");
 23             n = sc.nextInt();
 24             if(n == 1)
 25             {
 26                 addstudent();//添加学生；
 27             }
 28             else if(n == 2)
 29             {
 30                 erasestudent();//删除指定学号的学生
 31                     
 32             }
 33             else if(n == 3)
 34             {
 35                 editstudent();//修改指定学号的成绩
 36             }
 37             else if(n == 4)
 38             {
 39                 findstudent();//查找学生信息
 40             }
 41             else if(n == 5)
 42             {
 43                 printstudent();//打印所有学生的信息
 44             }
 45             else if(n == 6)
 46             {
 47                 savestudent();
 48                 System.exit(0);
 49                 break;
 50             }
 51         }
 52     }
 53 
 54     public static void savestudent() throws FileNotFoundException {
 55         PrintStream put = System.out;
 56         System.setOut(new PrintStream(new File("y.txt")));
 57         Iterator it = list.iterator();
 58         while(it.hasNext())
 59         {
 60             Object object = it.next();
 61             System.out.println(object);
 62         }
 63         System.setOut(put);
 64     }
 65 
 66     public static void readfile() throws FileNotFoundException {
 67         Scanner sc = new Scanner(new File("s.txt"));
 68         while(sc.hasNext())
 69         {
 70             String s = sc.nextLine();
 71             String []ss = s.split(" ");
 72             Student student = new Student(ss[0],ss[1],ss[2]);
 73             list.add(student);
 74         }
 75     }
 76 
 77     public static void printstudent() {
 78         for(int i = 0; i < list.size(); i ++)
 79         {
 80             System.out.println(list.get(i).toString());
 81         }
 82     }
 83 
 84     public static void findstudent() {
 85         String s;
 86         Scanner sc = new Scanner(System.in);
 87         System.out.println("请输入学号");
 88         s = sc.nextLine();
 89         for(int i = 0; i < list.size(); i ++)
 90         {
 91             if(list.get(i).getNo().equals(s))
 92             {
 93                 System.out.println(list.get(i).toString());
 94             }
 95         }
 96     }
 97 
 98     public static void editstudent() {
 99         String s,sco;
100         Scanner sc = new Scanner(System.in);;
101         System.out.println("请输入学号");
102         s = sc.nextLine();
103         for(int i = 0; i < list.size(); i ++)
104         {
105             if(list.get(i).getNo().equals(s))
106             {
107                 System.out.println("请输入修改后的成绩");
108                 sco = sc.nextLine();
109                 list.get(i).setScore(sco);
110             }
111         }
112     }
113 
114     public static void erasestudent() {
115         Scanner sc = new Scanner(System.in);
116         String s;
117         System.out.println("请输入指定的学号");
118         s = sc.nextLine();
119         for(int i = 0; i < list.size(); i ++)
120         {
121             if(list.get(i).getNo().equals(s))
122             {
123                 list.remove(i);
124             }
125         }
126     }
127 
128     public static void addstudent() {
129         String s; 
130         Scanner sc = new Scanner(System.in);
131         System.out.println("输出新同学的学号，姓名，成绩");
132         s = sc.nextLine();
133         String [] ss = s.split(" ");
134         Student student = new Student(ss[0],ss[1],ss[2]);
135         list.add(student);
136     }
137 }
138 
139 class Student
140 {
141     String no;
142     String name;
143     String score;
144     public Student() {
145         super();
146     }
147     public Student(String no, String name, String score) {
148         super();
149         this.no = no;
150         this.name = name;
151         this.score = score;
152     }
153     @Override
154     public String toString() {
155         return "Student [学号：" + no + ", 姓名：" + name + ", 成绩：" + score
156                 + "]";
157     }
158     @Override
159     public int hashCode() {
160         final int prime = 31;
161         int result = 1;
162         result = prime * result + ((name == null) ? 0 : name.hashCode());
163         result = prime * result + ((no == null) ? 0 : no.hashCode());
164         result = prime * result + ((score == null) ? 0 : score.hashCode());
165         return result;
166     }
167     public String getNo() {
168         return no;
169     }
170     public void setNo(String no) {
171         this.no = no;
172     }
173     public String getName() {
174         return name;
175     }
176     public void setName(String name) {
177         this.name = name;
178     }
179     public String getScore() {
180         return score;
181     }
182     public void setScore(String score) {
183         this.score = score;
184     }
185     
186 }

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