Java 为什么fileChannel.read循环永远不会结束？

我尝试使用nio读取仅包含5个字符的小文本，但是fileChannel.read循环永远不会结束

public static void main(String[] args) throws IOException {
        FileChannel fileChannel = FileChannel.open(Paths.get("input.txt"), StandardOpenOption.READ, StandardOpenOption.WRITE);
        ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
        while (fileChannel.read(byteBuffer) != -1) {
            byteBuffer.flip();
            while (byteBuffer.hasRemaining()) {
                char c = (char)byteBuffer.get();
                System.out.println(c);
            }
        }
    }

---

问题是，在内部

while

循环之后，您忘记重置缓冲区的限制和位置。读取前1024个字符后，缓冲区将满，每次尝试读取缓冲区时，将尝试读取最多

remaining=limit-position

字节，即缓冲区满后读取0字节

此外，您应该始终从

fileChannel.read（）

捕获返回值。在您的情况下，它会告诉您它正在连续返回

0

在内部循环解决问题后调用

byteBuffer.clear（）

：

public static void main(String[] args) throws IOException {
  FileChannel fileChannel = FileChannel.open(Paths.get("JPPFConfiguration.txt"), StandardOpenOption.READ, StandardOpenOption.WRITE);
  ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
  int n;
  long sum = 0L;
  while ((n = fileChannel.read(byteBuffer)) != -1) {
    sum += n;
    byteBuffer.flip();
    while (byteBuffer.hasRemaining()) {
      char c = (char) byteBuffer.get();
      System.out.print(c);
    }
    System.out.println("\n read " + n  + " bytes");
    byteBuffer.clear();
  }
  System.out.println("read " + sum + " bytes total");
}