將String轉換為Int。 字符串值=掃描儀輸入…很難解釋

Question

好吧，我正在嘗試轉換幾件事。

所以我已經將我的Scanner轉換為String，現在我要做的是，獲取他們輸入的值並將其用作其他if語句的整數。 它工作正常！

到目前為止，這是我的代碼：

import java.util.Scanner;
public class apples {
public static void main(String args[]) {

    Scanner fname = new Scanner(System.in);
    Scanner sname = new Scanner(System.in);
    Scanner number = new Scanner(System.in);
    tuna weight = new tuna();

    System.out.println("Enter Your First Name: ");
    String fname1 = fname.nextLine();
    String fnames = fname1;

    System.out.println("Enter Your Last Name: ");
    String sname1 = sname.nextLine();
    String snames = sname1;

    System.out.println("Enter Your Weight (Lbs.) : ");
    String num = number.nextLine();
    String num1 = num;

    System.out.println("Okay " + fname1 + " " + sname1
            + " I can see here that you weigh " + num + "lbs.");
    int num2 = num1.parseInt();
    if (num1 >= 275)
        System.out
                .println("You know, you should maybe consider laying off the candy my friend.....");
}

}

Answer 1

您應該在parseInt使用一個參數：

int num2 = Integer.parseInt(num1);

和

if (num2 >= 275) 
...

Answer 2

嘗試這個：

try{
  num2 = Integer.parseInt(num1);
}
catch(Exception ex) {
  System.out.println("Something went wrong, the string could not be converted to int.");
}

try-catch非常重要，因為該字符串可能包含無法轉換為int的字符，因此您需要比這更好地捕獲它，但請記住

Answer 3

您也可以使用其他類型的掃描儀方法來獲取int值

num = number.nextInt();

Answer 4

這是我所做的：

Scanner input = new Scanner(System.in);
System.out.println("Type number");
int number = input.nextInt();
System.out.println(number);

希望這可以幫助...

Answer 5

我自己不是Java專業人士，但我將您的代碼調整了一個檔次才能使其正常工作。 這里是。 很高興，如果有幫助。

p

ackage APPLE;
import java.util.Scanner;
public class apples {
public static void main(String args[]) {

    Scanner fname = new Scanner(System.in);
    Scanner sname = new Scanner(System.in);
    Scanner number = new Scanner(System.in);
    Scanner intScanner = new Scanner(System.in);

    System.out.println("Enter Your First Name: ");
    String fname1 = fname.nextLine();
    String fnames = fname1;

    System.out.println("Enter Your Last Name: ");
    String sname1 = sname.nextLine();
    String snames = sname1;

    System.out.println("Enter Your Weight (Lbs.) : ");
    int num = intScanner.nextInt();


    System.out.println("Okay " + " " + fname1 + " " + sname1 
            + " I can see here that you weigh " + num + "lbs.");

    if (num > 275){
        System.out.println("You know, you should maybe consider laying off the candy my friend.....");
    }
}
}