java - 检查文件结尾未按预期工作

Question

我尝试检查是否已到达文件末尾，但空字符串的条件不起作用

public void readEquation(String fileName) {  
        File aFile = new File(fileName);
        String line = null;
        int cnt = 0;
        try {
            FileReader reader = new FileReader(aFile);
            BufferedReader bufferedReader = new BufferedReader(reader);
            while ((line = bufferedReader.readLine()) != null) {      
                //but line gets null
                intoMap(line, cnt);
                cnt++;
            }
        } catch (IOException e1) {
            e1.printStackTrace();
        }
    }

Answer 1

您错误地一次读取两行而不是一行。循环的条件本身读取一行，然后在循环内读取另一行。我建议进行此更改:

public void readEquation(String fileName) {  
        File aFile = new File(fileName);
        String line = null;
        int cnt = 0;
        try {
            FileReader reader = new FileReader(aFile);
            BufferedReader bufferedReader = new BufferedReader(reader);
            line = bufferedReader.readLine();
            while (line != null) {                  
                intoMap(line, cnt);
                cnt++;
                line = bufferedReader.readLine();
            }
        } catch (IOException e1) {
            e1.printStackTrace();
        }
    }