.txtファイルを読み取り、学生のデータを抽出してコレクションに保存するプログラムを作成しています。次に、ユーザーはいくつかの異なるクエリを選択できるはずです。私が助けを求めているクエリは、たとえば 2014 年に卒業するすべての学生を選択し、これらの結果を画面に出力することです。
要するに、たとえば 2014 年に卒業する学生のクラスにArraylist保存されているスローを検索するにはどうすればよいですか? ProcessRecords何らかの理由で、特定の年に卒業した学生の記録を返すことができないようです。
以下は私のコードです。
最初のクラス: ProcessRecords (メイン メソッドを使用)
import java.util.*;
import java.io.*;
public class ProcessRecords {
public static void AskUser()
throws Exception {
Scanner preference = new Scanner(System.in);
//Creating a new scanner will allow us to gather user input
boolean flag=true;
//I will use this for my while loop
while (flag) {
System.out.println("What type of Search would you like to run?\n 1)Search for all students\n 2) Search for students graduating in a specific year\n 3)Search for students whose last name begins with a certain string\n");
int searchType=preference.nextInt();
//This variable will store what type of query the user would like to run
switch(searchType) {
case 1:
System.out.println("Gathering Records for all students\n");
//Call Query Method in the Query Class to return all students in the collection
break;
//Call Query Method in the Query Class to return all students in the colletion
case 2: System.out.println("What graduation year would you like to search for? \n");
String yearsearch=preference.next();
query.getYear(Integer.parseInt(yearsearch));
//getYear();
break;
//Call Query Method to return students who are graduating in the specified year
//Pass the "yearsearch" variable to the Query class
case 3:
System.out.println("What string would you like to search for? \n");
String lstsearch=preference.next();
break;
default:
System.out.println("Please pick a number between 1 and 3") ;
break;
//Call Query Method in the Query Class to return students who have the string in their last name
//Also I need to pass the "lstsearch" variable to the Query class to search through last names
}
}
}
public static void main(String[] args)
throws Exception
{
Scanner input = new Scanner(new File("students.txt"));
//This will import the file
input.nextLine();
//This will skip the headers in the file
System.out.println("Processing file now...");
//Let the user know that the file is being processed
int id;
String last;
String first;
int year;
int i=1;
// Declare variables that we will extract from the file
//Now we will being processing the file with a while loop
List<StudentRecord> studentRecords = new ArrayList<StudentRecord>();
while(input.hasNext())
{
id=input.nextInt();
last=input.next();
first=input.next();
year=input.nextInt();
StudentRecord record = new StudentRecord(id, last, first, year);
studentRecords.add(record);
System.out.println(id + " " + last + " " + first + " " + year + "\n");
}
System.out.println(" You have successfully read and printed from the file!");
for (StudentRecord s : studentRecords)
System.out.println(s.toString());
Query query = new Query(studentRecords);
}
}
2 番目のクラス: StudentRecord
import java.util.*;
public class StudentRecord
{
private int id;
private String last;
private String first;
private int year;
public StudentRecord(int id, String last, String first, int year)
{
this.id=id;
this.last=last;
this.first=first;
this.year=year;
}
public String toString()
{
return id + " " + last + " " + first + " " + year;
}
public int getYear()
{
return year;
}
3 番目のクラス: クエリ
import java.util.*;
import java.io.*;
public class Query
{
private List<StudentRecord> records;
public Query(List<StudentRecord> records) {
this.records = records;
}
public void getYear(int yearSearch) {
//I am trying to create a method to get students who are graduating in a specific year.
// I want to call this method in the ProcessRecord SwitchCase Case #2
int count = 0;
for(StudentRecord record : records) {
if(record.getYear() == yearSearch) {
System.out.println(record.toString());
count++;
}
}
}
}
質問
Arraylist特定の年に卒業する学生の学生記録を検索し、行全体を画面に出力する方法を理解するのを手伝ってくれれば、素晴らしいことです! 私はプログラミングに非常に慣れていないので、あなたが私に提供できるすべての助けに感謝します.