[英]Every row get same value in 2d array after assigning different values in java
'''
FileChannel channel = new FileInputStream("test.txt").getChannel();
MappedByteBuffer buffer = channel.map(FileChannel.MapMode.READ_ONLY, 0,50000);
byte[] data = new byte[102];
byte[][] bufferArray = new byte[(buffer.capacity() / 102)][100];
int i = 0;
while (buffer.hasRemaining()) {
int remaining = data.length;
if (buffer.remaining() < remaining)
remaining = buffer.remaining();
buffer.get(data, 0, remaining);
bufferArray[i++] = data;
System.out.println("Value before " + new String(bufferArray[43777]));
System.out.println("Value before 0 " + new String(bufferArray[0]));
System.out.println("Value before 100 " + new String(bufferArray[100]));
}
System.out.println("Value after 0 " + new String(bufferArray[0]));
System.out.println("Value after 100 " + new String(bufferArray[100]));
System.out.println("Value after 43777 " + new String(bufferArray[43777]));
''' * 之前的值不同,但之后的值都相同*缓冲区是从 txt 文件中读取的 MappedByteBuffer
在循环内移动数据数组初始化。 通过将其留在代码之外,重复覆盖相同的内存
FileChannel channel = new FileInputStream("test.txt").getChannel();
MappedByteBuffer buffer = channel.map(FileChannel.MapMode.READ_ONLY, 0,50000);
byte[] data;
byte[][] bufferArray = new byte[(buffer.capacity() / 102)][100];
int i = 0;
while (buffer.hasRemaining()) {
data = new byte[102];
int remaining = data.length;
if (buffer.remaining() < remaining)
remaining = buffer.remaining();
buffer.get(data, 0, remaining);
bufferArray[i++] = data;
System.out.println("Value before " + new String(bufferArray[43777]));
System.out.println("Value before 0 " + new String(bufferArray[0]));
System.out.println("Value before 100 " + new String(bufferArray[100]));
}
System.out.println("Value after 0 " + new String(bufferArray[0]));
System.out.println("Value after 100 " + new String(bufferArray[100]));
System.out.println("Value after 43777 " + new String(bufferArray[43777]));
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