Java读取文件 利用MappedByteBuffer进行缓冲

package sean;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.RandomAccessFile;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.util.Scanner;

public class Snippet {
public void readResource() {
long fileLength = 0;
final int BUFFER_SIZE = 0x300000;// 3M的缓冲

//for (String fileDirectory : this.readResourceDirectory())// 得到文件存放路径，我这里使用了一个方法从XML文件中读出文件的
// 存放路径，当然也可以用绝对路径来代替这里的fileDriectory
//{
File file = new File("D:\\MyData.txt");
fileLength = file.length();
try {
MappedByteBuffer inputBuffer = new RandomAccessFile(file, "r")
.getChannel().map(FileChannel.MapMode.READ_ONLY, 0,
fileLength);// 读取大文件

byte[] dst = new byte[BUFFER_SIZE];// 每次读出3M的内容

for (int offset = 0; offset < fileLength; offset += BUFFER_SIZE) {
if (fileLength - offset >= BUFFER_SIZE) {
for (int i = 0; i < BUFFER_SIZE; i++)
dst[i] = inputBuffer.get(offset + i);
} else {
for (int i = 0; i < fileLength - offset; i++)
dst[i] = inputBuffer.get(offset + i);
}
// 将得到的3M内容给Scanner，这里的XXX是指Scanner解析的分隔符
Scanner scan = new Scanner(new ByteArrayInputStream(dst))
.useDelimiter(" ");
while (scan.hasNext()) {
// 这里为对读取文本解析的方法
System.out.print(scan.next() + " ");
}
scan.close();
}
} catch (Exception e) {
e.printStackTrace();
}
//}
}
public static void main(String[] args)
{
Snippet sp = new Snippet();
sp.readResource();
}
}