Question

在下面的代码中，我将一个人的firstname和emailId保存在hashmap中。我希望打印以＆＃39; gmail.com＆＃39;结尾的emailId结尾的条目的名字。按升序排列。因为我使用了Java的TreeMap类。

但问题是打印emailId模式匹配的键..

public class RegExSolution {

public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    int N = in.nextInt();
    Map<String, String> emailDetail = new HashMap<>();
    for (int a0 = 0; a0 < N; a0++) {
        String firstName = in.next();
        String emailID = in.next();
        emailDetail.put(firstName, emailID);
    }
    Map<String, String> emailDetailTree = new TreeMap<>(emailDetail);

    Iterator i = emailDetailTree.entrySet().iterator();
    while (i.hasNext()) {
    i.next();
        if (Pattern.matches("[a-z]+@gmail\\.com$", "here I wish to get emaild from entry(i.e value from TreeMap)")) {
            System.out.println("here I wish to print the firstname(i.e. key from TreeMap) ");
        } else {
            continue;
        }
    }
}
}

提前致谢。

Answer 1

你丢弃了迭代器的结果。保留输入，您可以访问打印的键和值：

Iterator<Map.Entry<String, String>> i = emailDetailTree.entrySet().iterator();
while(i.hasNext()) {
    Map.Entry<String, String> entry = i.next();
    ...

从treemap对象中提取键

1 个答案: