querypage.java

来自「一个利用javabeanjsp产生联动分布的源代码」· Java 代码 · 共 125 行

//Source file: C:\\Rose2Java\\zhsoft\\dbcon\\QueryPage.java

package zhsoft.dbcon;


/**
 * 查询结果分页处理
 *
 * @author 雨亦奇([e-mail])
 * @version 1.0
 * @since 2003.05.18
 */
public class QueryPage
{

   /**
    * 每页行数
    */
   private int linesPerPage = 1;

   /**
    * 总页数
    */
   private int totalPages = 1;

   /**
    * 查询结果集
    */
   private QueryResult result = null;

   /**
    * @roseuid 3ED8688102EC
    */
   public QueryPage()
   {

   }

   /**
    * Access method for the linesPerPage property.
    *
    * @return   the current value of the linesPerPage property
    */
   public int getLinesPerPage()
   {
      return linesPerPage;
   }

   /**
    * Access method for the totalPages property.
    *
    * @return   the current value of the totalPages property
    */
   public int getTotalPages()
   {
      return totalPages;
   }

   /**
    * 初始化查询
    *
    * @param sql
    *  - 查询SQL语句
    * @param linesPerPage
    *  - 用户指定的每页行数
    * @throws java.lang.Exception
    * @roseuid 3ED8098600F8
    */
   public void init(String sql, int linesPerPage) throws Exception
   {
       if (linesPerPage<1) {
           throw new Exception("每页行数应大于等于1");
       }
       result = DBCon.runQuery(sql);
       this.linesPerPage = linesPerPage;
       totalPages = result.size()/linesPerPage;
       if (result.size()%linesPerPage!=0) {
           totalPages++;
       }
       if (totalPages==0) {
           totalPages = 1;
       }
   }

   /**
    * 是否已初始化
    *
    * @return boolean
    * @roseuid 3ED8098A0379
    */
   public boolean isInit()
   {
       if (result==null) {
           return false;
       } else {
           return true;
       }
   }

   /**
    * 返回指定页的查询结果
    *
    * @param pageno - 指定页号
    * @return ResultRow[]
    * @throws java.lang.Exception
    * @roseuid 3ED809A20388
    */
   public ResultRow[] getPage(int pageno) throws Exception
   {
       if (pageno<1||pageno>getTotalPages()) {
           throw new Exception("页号范围应为[1.."+getTotalPages()+"]");
       }
       ResultRow[] rr = null;
       if (pageno==getTotalPages()) {
           rr = new ResultRow[result.size()-(pageno-1)*linesPerPage];
       } else {
           rr = new ResultRow[linesPerPage];
       }
       for (int i=0;i<rr.length;i++) {
           rr[i] = (ResultRow)result.getRow((pageno-1)*linesPerPage+i).clone();
       }
       return rr;
   }
}