使用GZIP格式压缩文本以缩减文件大小，于是乎接触到了 GZIPInputStream/ GZIPOutputStream这两个类，还有 ByteArrayOutputStream这个类。这里写了一个简单的示例代码记录一下

import java.io.ByteArrayOutputStream;  
import java.io.File;  
import java.io.FileInputStream;  
import java.io.FileNotFoundException;  
import java.io.FileOutputStream;  
import java.io.IOException;  
import java.io.InputStream;  
import java.util.zip.GZIPInputStream;  
import java.util.zip.GZIPOutputStream;  
  
public class GZipFileTest {  
      
    private static final int BUFFER_SIZE = 1024;  
    /** 
     * @param args 
     */  
    public static void main(String[] args) {  
  
        File inputFile = new File("D:/test/input.txt");  
          
        File outputFile = new File("D:/test/test.dat");  
          
        writeGZip(inputFile,outputFile);  
          
        readGZip(outputFile);  
    }  
  
    public static void readGZip(File file) {  
          
        GZIPInputStream gzipInputStream = null;  
        ByteArrayOutputStream baos = null;  
        try {  
            gzipInputStream = new GZIPInputStream(new FileInputStream(file));  
              
            baos = new ByteArrayOutputStream();  
              
            byte[] buf = new byte[BUFFER_SIZE];  
            int len = 0;  
            while((len=gzipInputStream.read(buf, 0, BUFFER_SIZE))!=-1){  
                baos.write(buf, 0, len);  
            }  
              
            baos.toByteArray();  
              
            String result = baos.toString("UTF-8");  
              
            System.out.println("result="+result);  
              
        } catch (FileNotFoundException e) {  
            e.printStackTrace();  
        } catch (IOException e) {  
            e.printStackTrace();  
        }finally{  
            if(gzipInputStream!=null){  
                try {  
                    gzipInputStream.close();  
                } catch (IOException e) {  
                    e.printStackTrace();  
                }  
            }  
            if(baos!=null){  
                try {  
                    baos.close();  
                } catch (IOException e) {  
                    e.printStackTrace();  
                }  
            }  
        }  
    }  
      
    public static void writeGZip(File inputFile, File outputFile) {  
          
        GZIPOutputStream gzipOutputStream = null;  
        InputStream in = null;  
        try {  
            gzipOutputStream = new GZIPOutputStream(new FileOutputStream(outputFile));  
              
            in = new FileInputStream(inputFile);  
              
            byte[] buffer = new byte[BUFFER_SIZE];  
  
            int len = 0;  
            while ((len = in.read(buffer,0,BUFFER_SIZE)) > 0) {  
                gzipOutputStream.write(buffer, 0, len);  
            }  
            gzipOutputStream.finish();  
              
        } catch (FileNotFoundException e) {  
            e.printStackTrace();  
        } catch (IOException e) {  
            e.printStackTrace();  
        }finally{  
            if(gzipOutputStream!=null){  
                try {  
                    gzipOutputStream.close();  
                } catch (IOException e) {  
                    e.printStackTrace();  
                }  
            }  
            if(in!=null){  
                try {  
                    in.close();  
                } catch (IOException e) {  
                    e.printStackTrace();  
                }  
            }  
        }  
    }  
}