package org.phoenix.cases.kafka;import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import org.apache.commons.io.IOUtils;
import org.apache.commons.io.LineIterator;
import org.junit.Test;
/**
* 内存映射文件方式处理文件的实例
* @author mengfeiyang
*
*/
public class MappedBytes {
String filePath = "E:\\工作目录\\新项目\\凤舞一期\\backup\\new_show_style_json.txt";
/**
* 内存映射文件方式处理文件的实例
* @throws FileNotFoundException
* @throws IOException
*/
@SuppressWarnings("resource")
@Test
public void testMappedByte() throws FileNotFoundException, IOException {
long start = System.currentTimeMillis();
File file = new File(filePath);
long fileLength = file.length();
final int BUFFER_SIZE=0x500000;//5M
MappedByteBuffer inputBuffer = new RandomAccessFile(file,"rw").getChannel().map(FileChannel.MapMode.READ_WRITE, 0, fileLength);
byte[] dst = new byte[BUFFER_SIZE];
int count=0;
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);
}
String bs = new String(dst,"UTF-8");//将buffer中的字节转成字符串
String[] ns = bs.split("\n");
for(String s : ns){
if(s.contains(" -1- ")){
count++;
System.out.println(s.split("- 1 -")[0]);
}
}
System.out.println();
//String s = IOUtils.toString(new ByteArrayInputStream(dst));
//System.out.println(s);
}
System.out.println("总处理条数："+count);
long end = System.currentTimeMillis();
System.out.println((end - start)/1000);//处理809M的文件，90000条数据，只用了6秒
}
}
}
