java - 无法处理 ArrayIndexOutOfBoundsException

Question

我想分割字符串并将 token 分配给不同的字段，如果 token 大小不符合预期，则会抛出ArrayIndexOutOfBoundsException。当数据符合预期时，它显示空值。

示例代码:

public class Test {
    public static void main(final String[] args) {
         List<String> firstNames = new ArrayList<>();
         List<String> lastNames = new ArrayList<>();
         List<String> useCaseIds = new ArrayList<>();
         List<String> partner = new ArrayList<>();
         List<String> comments = new ArrayList<>();

         String s = "Annie-Marie--Joe"; // -NoData";
        // final String s = "Annie-Marie-83B782-Joe-NoData"; //showing empty value when printing the list.
         String[] tokens = s.split("-");

        switch (tokens.length) {
        case 1:
            firstNames.add(tokens[0]);
        case 2:
            lastNames.add(tokens[1]);
        case 3:
            useCaseIds.add(tokens[2]);
        case 4:
            partner.add(tokens[3]);
        case 5:
            comments.add(tokens[4]);
        default:
            break;
        }

        System.out.println("firstNames " + firstNames);
        System.out.println("lastNames " + lastNames);
        System.out.println("useCaseIds " + useCaseIds);
        System.out.println("partner " + partner);
        System.out.println("comments " + comments);
    }

}

输出:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 4

--编辑--修改代码如下所示。

final String s = "Annie-Marie-83B782-Joe"; // showing empty value when
// printing the list.
final String[] tokens = s.split("-");

switch (tokens.length) {
case 1:
    firstNames.add(tokens[0]);
    break;
case 2:
    lastNames.add(tokens[1]);
    break;
case 3:
    useCaseIds.add(tokens[2]);
    break;
case 4:
    partner.add(tokens[3]);
    break;
case 5:
    comments.add(tokens[4]);
    break;
default:
    break;
}

System.out.println("firstNames " + firstNames);
System.out.println("lastNames " + lastNames);
System.out.println("useCaseIds " + useCaseIds);
System.out.println("partner " + partner);
System.out.println("comments " + comments);

}

输出:

firstNames []
lastNames []
useCaseIds []
partner [Joe]
comments []

为什么在我的上述场景中，名字、姓氏...都是空白。

Answer 1

您必须在棘手的 switch 语句中使用不同的顺序:

import java.util.List;
import java.util.ArrayList;
public class Test {
    public static void main(final String[] args) {
         List<String> firstNames = new ArrayList<>();
         List<String> lastNames = new ArrayList<>();
         List<String> useCaseIds = new ArrayList<>();
         List<String> partner = new ArrayList<>();
         List<String> comments = new ArrayList<>();

         //String s = "Annie-Marie--Joe"; // -NoData";
         final String s = "Annie-Marie-83B782-Joe-NoData"; //showing empty value when printing the list.
         String[] tokens = s.split("-");

        switch (tokens.length) {
        case 5:
            comments.add(tokens[4]);                
        case 4:
            partner.add(tokens[3]);             
        case 3:
            useCaseIds.add(tokens[2]);
        case 2:
            lastNames.add(tokens[1]);
        case 1:
            firstNames.add(tokens[0]);
        default:
            break;
        }

        System.out.println("firstNames " + firstNames);
        System.out.println("lastNames " + lastNames);
        System.out.println("useCaseIds " + useCaseIds);
        System.out.println("partner " + partner);
        System.out.println("comments " + comments);
    }

}

在 jdoodle 上测试