java解压缩文件代码详解编程语言

/* 
** a simple unZIP tool 
** 
** ex.  java UnZip file.zip file1   to unzip file 1 from file.zip 
**      java UnZip file.zip         to unzip file.zip  
** 
*/ 
import java.io.*; 
import java.util.*; 
import java.util.zip.*; 
import java.text.*; 
 
class UnZip { 
  public static void main(String args[]) throws IOException { 
    InputStream in =  
      new BufferedInputStream(new FileInputStream(args[0])); 
    ZipInputStream zin = new ZipInputStream(in); 
    ZipEntry e; 
 
    while((e=zin.getNextEntry())!= null) { 
      if (args.length > 1) { 
        if (e.getName().equals(args[1])) { 
           unzip(zin, args[1]); 
           break; 
          } 
        } 
       unzip(zin, e.getName()); 
      } 
    zin.close(); 
    } 
 
  public static void unzip(ZipInputStream zin, String s)  
     throws IOException { 
    System.out.println("unzipping " + s); 
    FileOutputStream out = new FileOutputStream(s); 
    byte [] b = new byte[512]; 
    int len = 0; 
    while ( (len=zin.read(b))!= -1 ) { 
      out.write(b,0,len); 
      } 
    out.close(); 
    } 
}