为什么这个for循环在接收输入后无限地运行？ （Java）

Question

好吧，这段代码要求用户输入名称，年份和性别，并显示所选年份的名称排名。它从网址读取数据，并将其放入每年的地图中。然后将这些映射放入数组中，最后将等级显示给用户。进入while循环后，我的程序从未完成运行。下面是代码：

public static void main(String[] args) throws MalformedURLException, IOException { 
    Scanner input = new Scanner(System.in); 
    Map[] boyArray = new Map[10]; 
    Map[] girlArray = new Map[10]; 
    System.out.print("Enter year (between 2001 and 2010): "); 
    String year = input.nextLine(); 
    System.out.print("Enter gender (M or F): "); 
    String gender = input.nextLine(); 
    System.out.print("Enter name: "); 
    String name = input.nextLine(); 

    for (int i = 0; i < 10; i++) { 
     Map<String, String> boys = new HashMap<>(); 
     Map<String, String> girls = new HashMap<>(); 
     try { 
      java.net.URL url = new java.net.URL("http://www.cs.armstrong.edu/liang/data/babynamesranking"+ year + ".txt"); 
      Scanner urlInput = new Scanner(url.openStream()); 
      while (urlInput.hasNext()) { 
       String rank = input.next(); 
       boys.put(urlInput.next(), rank); 
       urlInput.next(); 
       girls.put(input.next(), rank); 
       urlInput.next(); 
      } 
     } 
     catch (IOException ex) { 
     } 
     boyArray[i] = boys; 
     girlArray[i] = girls; 
    } 
    if (gender.charAt(0) == 'M') { 
     System.out.println("The name " + name + " was ranked " + boyArray[Integer.parseInt(year) - 2001].get(name) + " in " + year); 
    } else { 
     System.out.println("The name " + name + " was ranked " + girlArray[Integer.parseInt(year) - 2001].get(name) + " in " + year); 
    } 

} 

}

Answer 1

它看起来像，作为@uthark已经指出的那样，你的程序是等待输入，因为在你的while循环你从System.in与线等待输入String rank = input.next();（和行girls.put(input.next(), rank);）。您可能的意思是编写String rank = urlInput.next();和girls.put(urlInput.next(), rank);，以便排名和女孩姓名来自http://www.cs.armstrong.edu/liang/data/babynamesranking YYYY .txt。