java實現zip與unzip

jdk提供了Zip 相關的類方便的實現壓縮和解壓縮。使用方法很簡單。下邊分別是壓縮和解壓縮的簡單事例
1，壓縮的

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

public class Zip {
    static final int BUFFER = 2048;

    public static void main(String argv[]) {
        try {
            BufferedInputStream origin = null;
            FileOutputStream dest = new FileOutputStream("E:\\test\\myfiles.zip");
            ZipOutputStream out = new ZipOutputStream(new BufferedOutputStream(
                    dest));
            byte data[] = new byte[BUFFER];
            File f = new File("e:\\test\\a\\");
            File files[] = f.listFiles();

            for (int i = 0; i < files.length; i++) {
                FileInputStream fi = new FileInputStream(files[i]);
                origin = new BufferedInputStream(fi, BUFFER);
                ZipEntry entry = new ZipEntry(files[i].getName());
                out.putNextEntry(entry);
                int count;
                while ((count = origin.read(data, 0, BUFFER)) != -1) {
                    out.write(data, 0, count);
                }
                origin.close();
            }
            out.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

 2，解壓縮的。

 

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.util.Enumeration;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

public class UnZip {
    static final int BUFFER = 2048;

    public static void main(String argv[]) {
        try {
            String fileName = "E:\\test\\myfiles.zip";
            String filePath = "E:\\test\\";
            ZipFile zipFile = new ZipFile(fileName);
            Enumeration emu = zipFile.entries();
            int i=0;
            while(emu.hasMoreElements()){
                ZipEntry entry = (ZipEntry)emu.nextElement();
                //會把目錄作為一個file讀出一次，所以只建立目錄就可以，之下的檔案還會被迭代到。
                if (entry.isDirectory())
                {
                    new File(filePath + entry.getName()).mkdirs();
                    continue;
                }
                BufferedInputStream bis = new BufferedInputStream(zipFile.getInputStream(entry));
                File file = new File(filePath + entry.getName());
                //加入這個的原因是zipfile讀取檔案是隨機讀取的，這就造成可能先讀取一個檔案
                //而這個檔案所在的目錄還沒有出現過，所以要建出目錄來。
                File parent = file.getParentFile();
                if(parent != null && (!parent.exists())){
                    parent.mkdirs();
                }
                FileOutputStream fos = new FileOutputStream(file);
                BufferedOutputStream bos = new BufferedOutputStream(fos,BUFFER);           
                
                int count;
                byte data[] = new byte[BUFFER];
                while ((count = bis.read(data, 0, BUFFER)) != -1)
                {
                    bos.write(data, 0, count);
                }
                bos.flush();
                bos.close();
                bis.close();
            }
            zipFile.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}