java中zip与gzip实现文件压缩，解压

GZIP对文件进行压缩解压，代码如下：

package cn.com.normal.io;import java.io.*;import java.util.zip.GZIPInputStream;import java.util.zip.GZIPOutputStream;/** * GZIP压缩和解压 */public class GZIP {    /**     * gzip文件压缩     * @param inputFile     * @param targetName     */    public void compressFile(File inputFile,String targetName) throws IOException {        System.out.println("程序开始...");        //字符输入流,以utf-8格式读入        BufferedReader in=new BufferedReader(new InputStreamReader(new FileInputStream(inputFile),"utf-8"));        //字符输出流        BufferedOutputStream out=new BufferedOutputStream(new GZIPOutputStream(new FileOutputStream(targetName)));        int n;        while ((n=in.read())!=-1){            out.write(String.valueOf((char) n).getBytes("utf-8"));        }        in.close();        out.close();        System.out.println("压缩完毕...");    }    /**     * 解压文件     * @param inputFile     * @param targetName     * @throws IOException     */    public void decompressFile(File inputFile,String targetName) throws IOException {        BufferedReader reader=new BufferedReader(new InputStreamReader(new GZIPInputStream(new FileInputStream(inputFile)),"utf-8"));        String s;        FileOutputStream fos=new FileOutputStream(targetName);        while ((s=reader.readLine())!=null){            fos.write(s.getBytes());        }        reader.close();        fos.close();        System.out.println("解压完毕...");    }}

ZIP对一个文件夹中的文件进行压缩和解压，代码如下：

package cn.com.normal.io;import java.io.*;import java.nio.charset.Charset;import java.util.zip.GZIPInputStream;import java.util.zip.ZipEntry;import java.util.zip.ZipInputStream;import java.util.zip.ZipOutputStream;/** * ZIP压缩方式 */public class ZIP {    private void _zip(String zipEntry,File file,ZipOutputStream out,BufferedOutputStream os) throws IOException {        if(file.isDirectory()){            File[] files=file.listFiles();            if(file.length()==0){                out.putNextEntry(new ZipEntry(zipEntry+File.separator));            }else{                for(File f:files){                    _zip(zipEntry+File.separator+f.getName(),f,out,os);                }            }        }else{            out.putNextEntry(new ZipEntry(zipEntry));            FileInputStream in=new FileInputStream(file);            BufferedInputStream bin=new BufferedInputStream(in);            int n;            while ((n=bin.read())!=-1){                os.write(n);            }            bin.close();            in.close();        }    }    public void zip(String output,File input) throws IOException {        FileOutputStream fos=new FileOutputStream(output);        ZipOutputStream out=new ZipOutputStream(fos);        BufferedOutputStream os=new BufferedOutputStream(out);        _zip(input.getName(),input,out,os);        os.close();        out.close();    }    public void unzip(String directory,String inputFile) throws IOException {        ZipInputStream zin=new ZipInputStream(new FileInputStream(inputFile));        BufferedInputStream bin=new BufferedInputStream(zin);        ZipEntry entry=null;        File file=null;        while ((entry=zin.getNextEntry())!=null&&!entry.isDirectory()){            file=new File(directory,entry.getName());            if(!file.exists()){                (new File(file.getParent())).mkdirs();            }            FileOutputStream out=new FileOutputStream(file);            BufferedOutputStream bout=new BufferedOutputStream(out);            int n;            while ((n=bin.read())!=-1){                bout.write(n);            }            out.close();            bout.close();        }        bin.close();        zin.close();    }}

小结：压缩文本文件一般通过字符操作压缩，压缩过程中指定编码的格式，解压过程中也通过指定解压的格式，最后获得准确解压文件，格式指定错误，将得到乱码的文件。