线程“main”中的异常java.lang.NumberFormatException：对于输入字符串：“t1”？

我是Java的新手,我在这里遇到了这个问题.我会发布链接并记住,这里的其他类似问题对我没有帮助,因为我有不同的代码,因此我在这里创建了这个帐户.

码：

package secret.package.guys;

import java.util.Scanner;

public class NewClass {
public static void main(String[] args) {

    System.out.println("Number: ");
    Scanner scanner = new Scanner(System.in); 
    String data=scanner.nextLine(); 
    System.out.println(data);


    int a = 0; 

    while(a < 6) {
        System.out.println(a);
        a  ; 
        }

    if (a > 6){ 
        System.out.println("SAFE SPACE");


    } else {
        System.out.println("Get in the Safe Space");
        System.out.println("PERSON has entered the Safe Space. Safe Space closes instantly.");
    }                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
    String s = new String("Old marks: ");
    String t = new String("5.5"); 
    String u = new String("4"); 
    String v = new String("3"); 
    String w = new String("2.5"); 
    String x = new String("6.0"); 
    String y = new String("5.2"); 
    String z = new String("4"); 

    String t1 = t.replaceAll("5.5", "6");
    String u1 = u.replaceAll("4", "4");
    String v1 = v.replaceAll("3", "5");
    String w1 = w.replaceAll("2.5", "3");
    String x1 = x.replaceAll("6.0", "2");
    String y1 = y.replaceAll("5.2", "1.8");
    String z1 = z.replaceAll("4", "4.4");
    System.out.println("New: "   s   " "   t1   " "   u1   " "   v1   " "   w1   " " 
      x1   " "   y1   " "   z1);
    System.out.println("Enter new marks: ");

    int foo = Integer.parseInt("t1"); 
    int foo1 = Integer.parseInt("u1"); 
    int foo2 = Integer.parseInt("v1"); 
    int foo3 = Integer.parseInt("w1"); 
    int foo4 = Integer.parseInt("x1"); 
    int foo5 = Integer.parseInt("y1"); 
    int foo6 = Integer.parseInt("z1"); 

    System.out.println("foo1   foo2   foo3   foo4   foo5   foo6");

}   

}

解决方法:

您必须在String变量的值上调用parseInt,而不是在变量名称上调用.

例如,

int foo = Integer.parseInt("t1"); 

应该

int foo = Integer.parseInt(t1); 

这只有在t1包含整数的String表示时才会起作用(这意味着parseInt(z1)和parseInt(y1)仍会失败,因为这些字符串不包含整数).

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