.txt ファイルを読み取り、学生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ために、ProcessRecords クラスに保存されている Arralist を検索するにはどうすればよいでしょうか? 別のクラスから呼び出す方法がわかりません。
以下は私のコードです：
ファーストクラス: main メソッドを使用
import java.util.*;
import java.io.*;
import java.lang.*;
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");
Query query = new Query(studentRecords);
int searchType=preference.nextInt();
//How would I throw an exception here if the user doesn't enter a number or enters a number less than 1 or great than 4
//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 colletion
case 2:
System.out.println("What graduation year would you like to search for? \n");
String yearsearch=preference.next();
//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();
//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());
}
}
二級生の記録
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;
}
}
サード クラス (私が助けを求めているもの)
import java.util.*;
import java.io.*;
public class Query
{
//public static ProcessRecords studentrecord = new ProcessRecords();
private List<StudentRecord> records;
public Query(List<StudentRecord> records) {
this.records = records;
}
public int getYear(int yearSearch) {
int count = 0;
for(StudentRecord record : records) {
if(record.getYear() == yearSearch) {
count++;
}
}
return count;
}
}
新しい投稿を追加しました!