Always close streams

Always close streams

import java.io.*;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.io.compress.CompressionCodec;
import org.apache.hadoop.io.compress.CompressionOutputStream;
import org.apache.hadoop.io.compress.GzipCodec;
import org.apache.hadoop.util.ReflectionUtils;

public class TestBlock2 {
	
	public static void main(String[] args) throws Exception {
//		Configuration conf = new Configuration();
//		Class<?> codecClass = Class.forName("org.apache.hadoop.io.compress.GzipCodec");
//		CompressionCodec codec = (CompressionCodec) ReflectionUtils.newInstance(codecClass, conf);
		CompressionCodec codec = new GzipCodec();
		
		InputStream in  = new FileInputStream(new File("a.txt"));
		
		File fileOut = new File("a.txt"+codec.getDefaultExtension());
		FileOutputStream outStream = new FileOutputStream(fileOut);
		
		CompressionOutputStream out = codec.createOutputStream(outStream);
		
		IOUtils.copyBytes(in, out, 4096, false);
		in.close();
//		out.close();
		outStream.close();
		
	}
}

　　测试该代码的时候，犯了个基础的错误，在流的关闭上没有把最后引用的流关闭。

即 out.close(); 导致的问题就是压缩流 CompressionOutputStream 没有把压缩的内容输出到文件中。

NOTE: 记得关闭相应的流。