BufferOverflowException的原因是什么？

本文介绍了BufferOverflowException的原因是什么？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

异常堆栈是

java.nio.BufferOverflowException at java.nio.DirectByteBuffer.put(DirectByteBuffer.java:327) at java.nio.ByteBuffer.put(ByteBuffer.java:813) mappedByteBuffer.put(bytes);

代码：

randomAccessFile = new RandomAccessFile(file, "rw"); fileChannel = randomAccessFile.getChannel(); mappedByteBuffer = fileChannel.map(MapMode.READ_WRITE, 0, file.length());

并调用 mappedByteBuffer.put（bytes）;

原因是什么 mappedByteBuffer.put（bytes） throws BufferOverflowException 如何查找原因？

What is the cause mappedByteBuffer.put(bytes) throws BufferOverflowException How to find the cause ?

推荐答案

FileChannel #map ：

此方法返回的映射字节缓冲区的位置为零，限制和容量大小;

The mapped byte buffer returned by this method will have a position of zero and a limit and capacity of size;

换句话说，如果 bytes.length> file.length <），你应该收到 BufferOverflowException 。

In other words, if bytes.length > file.length(), you should receive a BufferOverflowException.

要证明点，我测试了这段代码：

To prove the point, I have tested this code:

File f = new File("test.txt"); try (RandomAccessFile raf = new RandomAccessFile(f, "rw")) { FileChannel ch = raf.getChannel(); MappedByteBuffer buf = ch.map(MapMode.READ_WRITE, 0, f.length()); final byte[] src = new byte[10]; System.out.println(src.length > f.length()); buf.put(src); }

当且仅当 true ，抛出此异常：

Exception in thread "main" java.nio.BufferOverflowException at java.nio.DirectByteBuffer.put(DirectByteBuffer.java:357) at java.nio.ByteBuffer.put(ByteBuffer.java:832)