public static void main(String[] args) throws IOException { long timeStart = System.currentTimeMillis(); File file = new File("testData.txt");//文件路径 FileReader fileReader = new FileReader(file); LineNumberReader reader = new LineNumberReader(fileReader); int number = 99;//设置指定行数 String txt = ""; int lines = 0; while (txt != null) { lines++; txt = reader.readLine(); if (lines == number) { System.out.println("第" + reader.getLineNumber() + "的内容是：" + txt + "\n"); long timeEnd = System.currentTimeMillis(); System.out.println("总共花费：" + (timeEnd - timeStart) + "ms"); System.exit(0); } } reader.close(); fileReader.close(); }}原文：https://www.cnblogs.com/ysySelf/p/10468909.html