JSP高访问量下的计数程序

有时要为每一篇文章统计其点击次数，如果每一次浏览都要更新一次库的话，那性能在访问量很大的情况下，服务器的压力就会很大了，比较好一点的方法就是先将要更新的数据缓存起来，然后每隔一段时间再利用数据库的批量处理，批量更新库。源码如下：

    半分钟更新一次计数.

    count包中三个*.java文件

    1.CountBean.java

    package count;

    public class CountBean {  private String countType;

     int countId;

     public CountBean() {  }

     public void setCountType(String countTypes) {   this.countType = countTypes;  }

     public void setCountId(int countIds) {   this.countId = countIds;  }

     public String getCountType() {   return countType;  }

     public int getCountId() {   return countId;  } }

    2 CountCache.java

    package count;

    import java.util.*;

    public class CountCache {  public static LinkedList list = new LinkedList();

     public CountCache() {  }

     public static void add(CountBean cb) {   if (cb != null) {    list.add(cb);   }  }

    } 3.CountControl.java

    package count;

    import java.sql.*; import com.pp.db.*;

    public class CountControl {  private static long lastExecuteTime = 0;// 上次更新时间

     private static long executeSep = 30000;// 定义更新间隔时间，单位毫秒 半分钟

     public CountControl()
{
  }

     public synchronized void executeUpdate()
{
   Connection conn = null;
   PreparedStatement ps = null;
   try
{
    conn = new DBConnection().getConn();
    conn.setAutoCommit(false);
    ps = conn
      .prepareStatement("update t_news set hits=hits+1 where id=?");
    for (int i = 0; i < CountCache.list.size(); i++)
{
     CountBean cb = (CountBean) CountCache.list.getFirst();
     CountCache.list.removeFirst();
     ps.setInt(1, cb.getCountId());
     ps.executeUpdate();
    // ps.addBatch();
    }
   // int[] counts = ps.executeBatch();
    conn.commit();
   }
catch (Exception e)
{
    e.printStackTrace();
   }

 finally
{
    try
{
     if (ps != null)
{
      ps.clearParameters();
      ps.close();
      ps = null;
      conn.close();
     }
    }
catch (SQLException e) {    }

      }
  }

     public long getLast()
{
   return lastExecuteTime;
  }

     public void run()
{
   long now = System.currentTimeMillis();
   if ((now - lastExecuteTime) > executeSep)
{
     System.out.print("lastExecuteTime:"+lastExecuteTime);
     System.out.print(" now:"+now+"\n");
     System.out.print(" sep="+(now - lastExecuteTime)+"\n");
    lastExecuteTime=now;
    executeUpdate();
   }
   else
{
    System.out.print("wait for "+(now - lastExecuteTime)+" seconds:"+"\n");
   }
  }
}

    4.使用

    <% CountBean cb=new CountBean(); cb.setCountId(Integer.parseInt(request.getParameter("cid")));
  //计数的资源id CountCache.add(cb);
System.out.print(CountCache.list.size()+"<br>");
CountControl c=new CountControl();
c.run();
System.out.print(CountCache.list.size()+"<br>");
%>