ArrayList的<String>刪除查詢

Question

這裏是我的輸出：

-----Query----- 
[1]Update 
[2]Delete 
[3]Search 
[4]Show 
Choose Query:1 
Enter Your Student ID:1 
Enter Your First Name: Respo 
Enter Your Middle Name: Topher 
Enter Your Last Name: Raspo 
Do you want to back to Query?(Yes/No) 
Yes 
-----Query----- 
[1]Update 
[2]Delete 
[3]Search 
[4]Show 
Choose Query: 4 
12 
Christopher 
Reposo 
Porras 
1 
Respo 
Topher 
Raspo 

正如你可以在圖片中看到，我試圖讓沒有數據庫一個簡單的小系統，但使用ArrayList中包含這些數據我現在的問題是在刪除查詢。現在在刪除查詢中，我告訴用戶鍵入1的學生號碼，然後刪除它的信息和它的包含名字，中間名，姓氏的信息。但是我沒有太多邏輯在ArrayList中做這樣的事情。順便說一下，在這種情況下可能只使用一個ArrayList，或者我需要製作多個數組列表來解決我的問題。

public static void main(String[] args) { 
    //initialize Scanner for input process 
    Scanner scan = new Scanner(System.in); 

    //initialize needs variable 
    List<String> list = new ArrayList<String>(); 
    int choose,chooseQuery; 
    String chooseYesOrNo = " "; 
    String chooseYesOrNo2 = " ";  

    do { 
     //Startup Program 
     System.out.println("=====-----LibrarySystem-----====="); 
     System.out.println("[1]Student Information"); 
     System.out.println("[2]Book Information"); 
     System.out.print("Choose Table:"); 
     choose = scan.nextInt(); 

     do {    
      if(choose == 1) { 
       System.out.println("-----Query-----"); 
       System.out.println("[1]Update"); 
       System.out.println("[2]Delete"); 
       System.out.println("[3]Search"); 
       System.out.println("[4]Show"); 
       //reserved 
       //reserved 
       System.out.print("Choose Query:"); 
       chooseQuery = scan.nextInt(); 

       if(chooseQuery == 1) {      
        System.out.print("Enter Your Student ID:"); 
        String id = scan.next(); 
        list.add(id); 
        System.out.print("Enter Your First Name:"); 
        String name = scan.next(); 
        list.add(name); 
        System.out.print("Enter Your Middle Name:"); 
        String middle_name = scan.next(); 
        list.add(middle_name); 
        System.out.print("Enter Your Last Name:"); 
        String last_name = scan.next(); 
        list.add(last_name);   

        System.out.println("Do you want to back to Query?(Yes/No)"); 
        chooseYesOrNo = scan.next();        
       } else if (chooseQuery == 2) { //Delete Query 
        System.out.print("Enter Student ID:"); 
        String find_id = scan.next();        
       } else if(chooseQuery == 3) { //Search Query 

       } else if(chooseQuery == 4) { //Show Query 
        for (String s : list) { 
         System.out.println(s); 
        } 
       } 
      } 
     } while(chooseYesOrNo.equals("Yes")); 

     System.out.println("Do you want to get back at tables?(Yes/No)"); 
     chooseYesOrNo2 = scan.next();         
    } while(chooseYesOrNo2.equals("Yes")); 

    System.out.println("-----=====Program Terminated=====-----"); 
} 

Answer 1

1. 創建一個包含所有你需要的字段（學號，姓名等）

   class Student { 
       int studentId; 
       String firstname; 
       String middlename; 
       String lastname; 
   } 
   

2. 有一個數組列表Student對象

   java.util.List<Student> list = new java.util.ArrayList<Student>(); 
   

3. Student對象

   選擇刪除操作時，遍歷列表以查找對象並將其刪除。有關如何遍歷arraylist的nice blog。我最喜歡的方法如下：

   for (Student std:list) { 
       if (std.studentId == targetId) { 
       list.remove(std); 
       break; //since you've removed target, you can exit the loop 
       } 
   }