HOWTO · Java
스레드 기본 Java.Util.NoSuchElementException의 예외: 줄을 찾을 수 없음
이 자습서는 스레드 메인 java.util.NoSuchElementException의 예외를 해결하는 방법을 보여줍니다. Java에서 줄을 찾을 수 없습니다.
이 튜토리얼은 Java에서 스레드 "main" java.util.NoSuchElementException의 예외: 줄을 찾을 수 없음을 해결하는 방법을 보여줍니다.
스레드 "main"의 예외 java.util.NoSuchElementException: 줄을 찾을 수 없음
java.util.NoSuchElementException은 런타임 확인되지 않은 예외입니다. JVM은 next(), nextElement(), 반복자 또는 메소드 또는 열거와 같은 메소드를 사용할 때 이 예외를 발생시킵니다.
스레드 "main" 예외 java.util.NoSuchElementException: 라인을 찾을 수 없음 오류는 스캐너를 사용하여 nextLine()과 같은 메서드로 사용자 입력을 가져올 때 발생합니다. 경계 없이 메서드를 사용하려고 하면 오류가 발생합니다.
이 오류를 보여주는 예를 살펴보겠습니다.
package delftstack;
import java.util.Scanner;
public class Example {
static boolean[][] Articles;
public static void main(String[] args) {
// This initiates all array values to be false
Articles = new boolean[4][4];
for (int i = 0; i < 4; i++) {
for (int j = 0; j < 4; j++) {
Articles[i][j] = false;
}
// Welcome message
System.out.println("-------------------------");
System.out.println("Welcome to Delftstack.com.");
System.out.println("-------------------------\n");
// Starts program
Programstart();
}
}
public static void Programstart() {
// to read users' input
Scanner sc = new Scanner(System.in);
// user input
String Requested_Lanuguage;
String Requested_Article;
// Counters for articles array
int Count_Language = 0;
int Count_Artciles = 0;
// User to select their choice of Programming Language
System.out.print("Please type 1 for Java or 2 for Python: ");
// Language preference
Requested_Lanuguage = sc.nextLine();
switch (Requested_Lanuguage) {
case "1":
// User selects Java
System.out.println(">>> You have selected Java. \n");
break;
case "2":
// User selects Python
System.out.println(">>> You have selected Python. \n");
break;
default:
// User has not selected a valid Programming Language
System.out.println(">>> You have not selected a valid choice. Please try again. \n");
Programstart();
break;
}
// user to select their choice of article
System.out.print("Please type 1 for Web and 2 for App: ");
// Article preference
Requested_Article = sc.nextLine();
switch (Requested_Article) {
case "1":
// User selects Web Articles
System.out.println(">>> You have selected Web Articles. \n");
break;
case "2":
// User selects App Articles
System.out.println(">>> You have selected App Articles. \n");
break;
default:
// User has not selected a valid article
System.out.println(">>> You have not selected a choice. Please try again. \n");
Programstart();
break;
}
// Closes Scanner
sc.close();
}
}
위 코드의 출력은 다음과 같습니다.
-------------------------
Welcome to Delftstack.com.
-------------------------
Please type 1 for Java or 2 for Python: 1
>>> You have selected Java.
Please type 1 for Web and 2 for App: 1
>>> You have selected Web Articles.
Exception in thread "main" -------------------------
Welcome to Delftstack.com.
-------------------------
Please type 1 for Java or 2 for Python: java.util.NoSuchElementException: No line found
at java.base/java.util.Scanner.nextLine(Scanner.java:1651)
at delftstack.Example.Programstart(Example.java:45)
at delftstack.Example.main(Example.java:24)
경계 없이 nextLine() 메서드를 사용하기 때문에 오류가 발생합니다. 이 문제를 해결하려면 Requested_Article = sc.nextLine(); 코드를 교체해야 합니다. 다음 코드로.
while (sc.hasNextLine()) {
Requested_Article = sc.nextLine();
// Switch condition here
}
해결책을 시도해 봅시다.
package delftstack;
import java.util.Scanner;
public class Example {
static boolean[][] Articles;
public static void main(String[] args) {
// This initiates all array values to be false
Articles = new boolean[4][4];
for (int i = 0; i < 4; i++) {
for (int j = 0; j < 4; j++) {
Articles[i][j] = false;
}
// Welcome message
System.out.println("-------------------------");
System.out.println("Welcome to Delftstack.com.");
System.out.println("-------------------------\n");
// Starts program
Programstart();
}
}
public static void Programstart() {
// to read users' input
Scanner sc = new Scanner(System.in);
// user input
String Requested_Lanuguage;
String Requested_Article;
// Counters for articles array
int Count_Language = 0;
int Count_Artciles = 0;
// User to select their choice of Programming Language
System.out.print("Please type 1 for Java or 2 for Python: ");
// Language preference
Requested_Lanuguage = sc.nextLine();
switch (Requested_Lanuguage) {
case "1":
// User selects Java
System.out.println(">>> You have selected Java. \n");
break;
case "2":
// User selects Python
System.out.println(">>> You have selected Python. \n");
break;
default:
// User has not selected a valid Programming Language
System.out.println(">>> You have not selected a valid choice. Please try again. \n");
Programstart();
break;
}
// user to select their choice of article
System.out.print("Please type 1 for Web and 2 for App: ");
// Article preference
while (sc.hasNextLine()) {
Requested_Article = sc.nextLine();
switch (Requested_Article) {
case "1":
// User selects Web Articles
System.out.println(">>> You have selected Web Articles. \n");
break;
case "2":
// User selects App Articles
System.out.println(">>> You have selected App Articles. \n");
break;
default:
// User has not selected a valid article
System.out.println(">>> You have not selected a choice. Please try again. \n");
Programstart();
break;
}
}
// Closes Scanner
sc.close();
}
}
위의 코드는 이제 Exception in thread "main" java.util.NoSuchElementException: No line found를 발생시키지 않습니다. 출력을 참조하십시오.
-------------------------
Welcome to Delftstack.com.
-------------------------
Please type 1 for Java or 2 for Python: 1
>>> You have selected Java.
Please type 1 for Web and 2 for App: 1
>>> You have selected Web Articles.
1
>>> You have selected Web Articles.
>>> You have not selected a choice. Please try again.
Please type 1 for Java or 2 for Python:
