为什么我输入$后不会退出while循环

时间:2015-03-14 19:03:57

标签: java while-loop

当我输入$时,我会期望退出while循环,但它会继续循环。谢谢你的帮助

import java.io.*; 
import java.util.*;

public class test {

    public static void main(String[] args) {

        String oneLine = "";
        try {
            BufferedReader indata = new
                    BufferedReader(new InputStreamReader(System.in));

            while (!oneLine.equals("$")) {

                oneLine = indata.readLine();
                System.out.println(oneLine);
            }
        }
        catch (Exception e) {
            System.out.println("Error --" + e.toString());
        }
        System.out.println("outside of while \n");
        return;
    }
}

1 个答案:

答案 0 :(得分:0)

将您的代码更改为:

String oneLine = "";
while ( !oneLine.equals ("$") && oneLine != null){
   oneLine = indata.readLine();
   System.out.println(oneLine); 
}

您正在将BufferedReader对象与String进行比较。我相信你想要与现有的线路进行比较。同样如评论中所述 - 您需要将oneLine初始化为非空值,以便在您第一次进入while循环时避免NullPointerException