解压/压缩zip包

压缩/解压采用org.apache.tools.zip包，相对其他压缩/解压包，这个支持中文比较好

1.解压zip文件

   //解压文件
  public synchronized void unzip(String zipFileName, String extPlace,
                                 boolean whether) throws Exception {
    try {
      (new File(extPlace)).mkdirs();
      File f = new File(zipFileName);
      ZipFile zipFile = new org.apache.tools.zip.ZipFile(zipFileName);
      //zipFile = new ZipFile(zipFileName);
      if ( (!f.exists()) && (f.length() <= 0)) {
        throw new Exception("要解压的文件不存在!");
      }
      String strPath, gbkPath, strtemp;
      File tempFile = new File(extPlace);
      strPath = tempFile.getAbsolutePath();
      java.util.Enumeration e = zipFile.getEntries();
      while (e.hasMoreElements()) {
        org.apache.tools.zip.ZipEntry zipEnt = (org.apache.tools.zip.ZipEntry)
            e.nextElement();
        gbkPath = zipEnt.getName();
        if (zipEnt.isDirectory()) {
          strtemp = strPath + File.separator + gbkPath;
          File dir = new File(strtemp);
          dir.mkdirs();
          continue;
        }
        else {
          //读写文件
          InputStream is = zipFile.getInputStream(zipEnt);
          BufferedInputStream bis = new BufferedInputStream(is);
          gbkPath = zipEnt.getName();
          strtemp = strPath + File.separator + gbkPath;

          //建目录
          String strsubdir = gbkPath;
          for (int i = 0; i < strsubdir.length(); i++) {
            if (strsubdir.substring(i, i + 1).equalsIgnoreCase("/")) {
              String temp = strPath + File.separator + strsubdir.substring(0, i);
              File subdir = new File(temp);
              if (!subdir.exists()) {
                subdir.mkdir();
              }
            }
          }
          FileOutputStream fos = new FileOutputStream(strtemp);
          BufferedOutputStream bos = new BufferedOutputStream(fos);
          int c;
          while ( (c = bis.read()) != -1) {
            bos.write( (byte) c);
          }
          bos.close();
          fos.close();
        }
      }
    }
    catch (Exception e) {
      e.printStackTrace();
      throw e;
    }
  }

2.压缩，直接从数据库读出文件列表，动态加入zip文件包中下载，无需服务器端保留文件

  <%@page contentType="text/html;charset=GBK" import="com.jspsmart.upload.*"%>
<%@page import="com.tiantium.contractsub.util.*"%>
<%@page import="java.sql.*,java.util.*,java.io.*,oracle.sql.*,java.util.Vector"%>
<%@page import="org.apache.tools.zip.*"%>
<%
  Connection conn = null;
  PreparedStatement pre = null;
  ResultSet rs = null;
  String fileName="download.zip";

  try {
    com.tiantium.contractsub.util.DBUtil dbUtil = new com.tiantium.contractsub.util.DBUtil();
    conn = dbUtil.getConnection();
   
    String sql = "select file_name,file_content from contsub_upload_file";

    pre = conn.prepareStatement(sql);
    // 查询BLOB对象
    rs = pre.executeQuery();
    //建立压缩输出流
    response.setContentType( "application/x-zip-compressed" );
    response.setHeader( "Content-Disposition" , "inline; filename="+fileName);
    ServletOutputStream sos=response.getOutputStream();
    ZipOutputStream outZip=new ZipOutputStream(new BufferedOutputStream(sos));

    while (rs.next()) {
       //添加文件到zip压缩包
       outZip.putNextEntry(new ZipEntry(rs.getString("file_name")));
       oracle.sql.BLOB blob = (oracle.sql.BLOB) rs.getBlob("file_content");
       InputStream is = blob.getBinaryStream();
       byte[] buffer = new byte[4000];
       int length;
       while ((length = is.read(buffer)) != -1){
        outZip.write(buffer, 0, length);
       }
       is.close();
    }
    outZip.close();
  }
  catch (Exception e) {
    e.printStackTrace();
  }
  finally {
    DBAssistant.closeRSC(rs, pre, conn);
  }

%>