google snapy 壓縮文件

引入 google snappy 包

github 上snappy地址 http://github.com/google/snappy

org.xerial.snappy
snappy-java
1.1.2.6

使用snappy壓縮文件

import java.io.ByteArrayOutputStream;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

import org.xerial.snappy.Snappy;

public class SnappyDemo {

public static void main(String[] args) throws Exception {
// 待壓縮的文件,可以是任意文件
RandomAccessFile raf = new RandomAccessFile("c:/花好月圓夜.mp4", "r");
//壓縮後保存的文件
RandomAccessFile w = new RandomAccessFile("c:/cas-server-3.5.2-master.snappy", "rw");
FileChannel channel = raf.getChannel;
ByteBuffer buffer = ByteBuffer.allocate(4096);
ByteArrayOutputStream out = new ByteArrayOutputStream(1024);
while (channel.read(buffer) > -1) {
buffer.flip ;

while(buffer.hasRemaining){
out.write( buffer.get );
}
buffer.clear ;
}
//壓縮內容寫入 文件，如果文件比較大 壓縮後的文件可以分多個文件保存，
// 例如hadoop 文件每個塊自定義為128M
w.write( Snappy.compress(out.toByteArray) );
raf.close;
w.close;
out.close;
}
}

使用snappy解壓縮

import java.io.ByteArrayOutputStream;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

import org.xerial.snappy.Snappy;

public class UnSnappyDemo {

public static void main(String[] args) throws Exception {
RandomAccessFile raf = new RandomAccessFile("c:/cas-server-3.5.2-master.snappy", "r");
RandomAccessFile w = new RandomAccessFile("c:/cas-server-3.5.2-master.zip", "rw");
FileChannel channel = raf.getChannel;
ByteBuffer buffer = ByteBuffer.allocate(196);
ByteArrayOutputStream out = new ByteArrayOutputStream(1024);
while (channel.read(buffer) > -1){
buffer.flip ;
while(buffer.hasRemaining){
out.write( buffer.get );
}
buffer.clear ;
buffer = ByteBuffer.allocate(196);
}
w.write( Snappy.uncompress(out.toByteArray) );
raf.close;
w.close;
}
}

喜歡這篇文章嗎？立刻分享出去讓更多人知道吧！