Java BufferedReader readLine 方法不返回任何内容

Question

我有一个问题需要解决:http://www.urionlinejudge.com.br/judge/problems/view/1117

使用我的代码，当代码到达最后一行时，readLine 方法不会返回任何内容。它等待我输入另一行输入。

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

public class ValidacaoDeNota {
   public static void main(String[] args) throws IOException {
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

      String line = null;
      double num;

      Double ultimaNotaValida = null;

      while ((line=br.readLine()) != null) {
         num = Double.parseDouble(line);

         if (num < 0 || num > 10) {
            bw.write("nota invalida");
         } else if (ultimaNotaValida == null) {
            ultimaNotaValida = num;
         } else {
            bw.write("media = " + ((ultimaNotaValida+num) / 2) );
         }

         bw.write("\n");
      }

      bw.flush();
   }
}

Answer 1

您需要输入 Ctrl/d (Windows) 或 Ctrl/z(Unix、Linux 等)才能在控制台产生流结束。然后 readLine() 将返回 null 并且循环将终止。