java - 编译器不会让 String 变量出现在 switch 语句中

Question

在为我的应用程序设定任何条件之前，我需要能够让 switch 语句在 while 循环下运行。据说它无法在1.7以下的任何编译器下工作。 JRE。我不知道这意味着什么，也不知道如何将变量更改为枚举类型。

package PokerApp;
import java.util.Scanner;
public class PokerApp {

    public static void main(String[] args) {

int card1 = 0;
int card2 = 0;
int play;
String fc1 = "", fc2 ="";
String answer = "";

Scanner scan = new Scanner(System.in);

//**************************************
//              Card1
//**************************************
System.out.println("Press 1 to evalaute your cards: ");
play = scan.nextInt();
while (play != 0){

System.out.println("First Card: ");
if (scan.hasNextInt())
{
    card1 = scan.nextInt(9)+2;
}
else{
    fc1 = scan.next();
    switch(fc1)
    {
    case "A":
        card1 = 14;
        break;
    case "K":
        card1 = 13;
        break;
    case "Q":
        card1 = 12;
        break;
    case "J":
        card1 = 11;
        break;
        default:System.out.println("Incvalid entry");
    }
//***************************************
//              Card2
//***************************************

System.out.println("Second card: ");
if (scan.hasNextInt())
{
    card2 = scan.nextInt(9) +2;
}
else{
    fc2 = scan.next();
    switch (fc2)
    {
    case "A":
        card2 = 14;
        break;
    case "K":
        card2 = 13;
        break;
    case "Q":
        card2 = 12;
        break;
    case "J":
        card2 = 11;
        break;
    default:System.out.println("Invalid entry.");
    }

    }
}

    }

}
}

Answer 1

Allowing Strings in switch statements was new in Java 1.7.将 Java 升级到 1.7+ 并在 Eclipse 中使用它，或者如果不能，则必须将案例转换为 if-else 语句。