Java 读写GZIP格式文件代码详解编程语言

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();   
                }   
            }   
        }   
    }   
}