java gzip压缩解压缩代码详解编程语言

java Gzip压缩实现代码

import java.io.FileInputStream;  
import java.io.FileNotFoundException;  
import java.io.FileOutputStream;  
import java.io.IOException;  
import java.util.zip.GZIPOutputStream;  
 
public class CompressFileGZIP {  
private static void doCompressFile(String inFileName) {  
 
        try {  
 
            System.out.println("Creating the GZIP output stream.");  
            String outFileName = inFileName + ".gz";  
            GZIPOutputStream out = null;  
            try {  
                out = new GZIPOutputStream(new FileOutputStream(outFileName));  
            } catch(FileNotFoundException e) {  
                System.err.println("Could not create file: " + outFileName);  
                System.exit(1);  
            }  
 
            System.out.println("Opening the input file.");  
            FileInputStream in = null;  
            try {  
                in = new FileInputStream(inFileName);  
            } catch (FileNotFoundException e) {  
            System.err.println("File not found. " + inFileName);  
                System.exit(1);  
            }  
 
            System.out.println("Transfering bytes from input file to GZIP Format.");  
            byte[] buf = new byte[1024];  
            int len;  
            while((len = in.read(buf)) > 0) {  
                out.write(buf, 0, len);  
            }  
            in.close();  
 
            System.out.println("Completing the GZIP file");  
            out.finish();  
            out.close();  
 
        } catch (IOException e) {  
            e.printStackTrace();  
            System.exit(1);  
        }  
 
    }  
 
    /**  
     * Sole entry point to the class and application.  
     * @param args Array of String arguments.  
     */  
    public static void main(String[] args) {  
    String str="E://AUTORUN.INF";  
 
            doCompressFile(str);  
 
    }  
} 

java Gzip解压缩代码

import java.util.zip.GZIPInputStream;  
import java.io.FileOutputStream;  
import java.io.FileInputStream;  
import java.io.FileNotFoundException;  
import java.io.IOException;  
 
public class UncompressFileGZIP {  
 
    /**  
     * Uncompress the incoming file.  
     * @param inFileName Name of the file to be uncompressed  
     */  
    private static void doUncompressFile(String inFileName) {  
 
        try {  
 
            if (!getExtension(inFileName).equalsIgnoreCase("gz")) {  
                System.err.println("File name must have extension of /".gz/"");  
                System.exit(1);  
            }  
 
            System.out.println("Opening the compressed file.");  
            GZIPInputStream in = null;  
            try {  
                in = new GZIPInputStream(new FileInputStream(inFileName));  
            } catch(FileNotFoundException e) {  
                System.err.println("File not found. " + inFileName);  
                System.exit(1);  
            }  
 
            System.out.println("Open the output file.");  
            String outFileName = getFileName(inFileName);  
            FileOutputStream out = null;  
           try {  
                out = new FileOutputStream(outFileName);  
            } catch (FileNotFoundException e) {  
                System.err.println("Could not write to file. " + outFileName);  
                System.exit(1);  
            }  
 
            System.out.println("Transfering bytes from compressed file to the output file.");  
            byte[] buf = new byte[1024];  
            int len;  
            while((len = in.read(buf)) > 0) {  
                out.write(buf, 0, len);  
            }  
 
            System.out.println("Closing the file and stream");  
            in.close();  
            out.close();  
 
        } catch (IOException e) {  
            e.printStackTrace();  
            System.exit(1);  
        }  
 
    }  
 
    /**  
     * Used to extract and return the extension of a given file.  
     * @param f Incoming file to get the extension of  
     * @return <code>String</code> representing the extension of the incoming  
     *         file.  
     */  
    public static String getExtension(String f) {  
        String ext = "";  
        int i = f.lastIndexOf('.');  
 
        if (i > 0 &&  i < f.length() - 1) {  
            ext = f.substring(i+1);  
        }       
        return ext;  
    }  
 
    /**  
     * Used to extract the filename without its extension.  
     * @param f Incoming file to get the filename  
     * @return <code>String</code> representing the filename without its  
     *         extension.  
     */  
    public static String getFileName(String f) {  
        String fname = "";  
        int i = f.lastIndexOf('.');  
 
        if (i > 0 &&  i < f.length() - 1) {  
            fname = f.substring(0,i);  
        }       
        return fname;  
    }  
 
    /**  
     * Sole entry point to the class and application.  
     * @param args Array of String arguments.  
     */  
    public static void main(String[] args) {  
 
            doUncompressFile("E://AUTORUN.INF.gz");  
 
    }  
 
}