使用BufferedReader读取文本文件 [英] Using BufferedReader to read Text File

问题描述

我使用BufferedReader有问题

I'm having problems with using the BufferedReader

我想打印文本文件的6行：

I want to print the 6 lines of a text file:

public class Reader {

public static void main(String[]args) throws IOException{

    FileReader in = new FileReader("C:/test.txt");
    BufferedReader br = new BufferedReader(in);

    while (br.readLine() != null) {
        System.out.println(br.readLine());
    }
    in.close();

}

现在我每次调用readLine （）方法会自动前进到下一行。

Now from what I can gather every time I call the readLine() method it automatically advances to the next line.

所以我不能使用条件br.readLine（）！= null，因为它已经提前一个行，我得到输出：

So I can't use the condition br.readLine() != null since it'll already advance it one line and I get the output:

Line 2
Line 4
Line 6

我使用什么条件来检查文本字段中是否还有一行。

What Condition do I use to check if there is still a new line in the text field.

提前感谢！

推荐答案

这是问题：

while (br.readLine() != null) {
    System.out.println(br.readLine());
}

您有两个调用 readLine - 第一个只有检查有一行（但读取它并将其丢弃），第二个读取下一个行。你想要：

You've got two calls to readLine - the first only checks that there's a line (but reads it and throws it away) and the second reads the next line. You want:

String line;
while ((line = br.readLine()) != null) {
    System.out.println(line);
}

现在我们只调用 readLine（） / code> 一次循环迭代，并使用我们已经读过的我们完成了的行？和打印出行部分。

Now we're only calling readLine() once per loop iteration, and using the line that we've read both for the "have we finished?" and "print out the line" parts.

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