Question

我正在尝试编写一个处理读取文件的类。为了逐字阅读文件，我使用了以下在互联网上找到的代码。 Netbeans似乎不同意并说它无法在while循环中找到符号br。

public class Reader {
  public String file2string() {
    String line;
    try (InputStream fis = new FileInputStream("smth")) {
      InputStreamReader isr = new InputStreamReader(fis, Charset.forName("UTF-8"));
      BufferedReader br = new BufferedReader(isr);
    } catch (IOException ex) {
      Logger.getLogger(Reader.class.getName()).log(Level.SEVERE, null, ex);
    }
    {
      while ((line = br.readLine()) != null) {
        String[] words = line.split(" ");
        // Now you have a String array containing each word in the current line
      }
    }
    return line;
  }
}

Answer 1

您的try语句后有{}个阻止

{
    InputStreamReader isr = new InputStreamReader(fis, Charset.forName("UTF-8"));
    BufferedReader br = new BufferedReader(isr);
}

然后你有另一个{}阻止。

{
    while ((line = br.readLine()) != null) {
        String[] words = line.split(" ");
        // Now you have a String array containing each word in the current line
    }
}

第一个块中声明的变量在第二个块中不可见。

结合两个区块：

public String file2string() {
    String line;
    try (InputStream fis = new FileInputStream("smth")) {
        InputStreamReader isr = new InputStreamReader(fis, Charset.forName("UTF-8"));
        BufferedReader br = new BufferedReader(isr);
        while ((line = br.readLine()) != null) {
            String[] words = line.split(" ");           
        }
        return line;
    } catch (IOException ex) {
        Logger.getLogger(Reader.class.getName()).log(Level.SEVERE, null, ex);
    }
    // you need to decide what you want to return here if you got an exception.
}

您似乎正在拆分每一行并忽略结果，然后返回文件的最后一行。我不知道你为什么这样做，或者你真正想做的事情;但这是修复编译错误的方法。

Answer 2

变量＆＃34; br＆＃34;在try {}块中声明，以便它的范围。它不会在那个街区之外可见。尝试将while循环放在try块中。

Answer 3

您的循环超出了try，因此变量br在上下文中是未知的。将while-loop放在try结构中，如下所示：

public String file2string() {
    String line = null;
    try (InputStream fis = new FileInputStream("smth")) {
        InputStreamReader isr = new InputStreamReader(fis, Charset.forName("UTF-8"));
        BufferedReader br = new BufferedReader(isr);

        while ((line = br.readLine()) != null) {
            String[] words = line.split(" ");
            // Now you have a String array containing each word in the current line
        }
    } catch (IOException ex) {
        Logger.getLogger(Reader.class.getName()).log(Level.SEVERE, null, ex);
    }  
    return line;
}

BufferReader里面的try子句：找不到符号

3 个答案: