浙江20选5中奖:JSP高訪問量下的計數程序

浙江20选5开奖结果走势图 www.kcvsu.com 10/25/2006來源:JSP實例人氣:29380

  有時要為每一篇文章統計其點擊次數,如果每一次瀏覽都要更新一次庫的話,那性能在訪問量很大的情況下,服務器的壓力就會很大了,比較好一點的方法就是先將要更新的數據緩存起來,然后每隔一段時間再利用數據庫的批量處理,批量更新庫。源碼如下:

  CountBean.java

/*
* CountData.java
*
* Created on 2006年10月18日, 下午4:44
*
* To change this template, choose Tools | Options and locate the template under
* the Source Creation and Management node. Right-click the template and choose
* Open. You can then make changes to the template in the Source Editor.
*/

  package com.tot.count;

/**
*
* @author //www.tot.name
*/
public class CountBean {
 PRivate String countType;
 int countId;
 /** Creates a new instance of CountData */
 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;
 }
}

  CountCache.java

/*
* CountCache.java
*
* Created on 2006年10月18日, 下午5:01
*
* To change this template, choose Tools | Options and locate the template under
* the Source Creation and Management node. Right-click the template and choose
* Open. You can then make changes to the template in the Source Editor.
*/

package com.tot.count;
import java.util.*;
/**
*
* @author //www.tot.name
*/
public class CountCache {
 public static LinkedList list=new LinkedList();
 /** Creates a new instance of CountCache */
 public CountCache() {}
 public static void add(CountBean cb){
  if(cb!=null){
   list.add(cb);
  }
 }
}

 CountControl.java

 /*
 * CountThread.java
 *
 * Created on 2006年10月18日, 下午4:57
 *
 * To change this template, choose Tools | Options and locate the template under
 * the Source Creation and Management node. Right-click the template and choose
 * Open. You can then make changes to the template in the Source Editor.
 */

package com.tot.count;
import tot.db.DBUtils;
import java.sql.*;
/**
*
* @author //www.tot.name
*/
public class CountControl{
 private static long lastExecuteTime=0;//上次更新時間 
 private static long executeSep=60000;//定義更新間隔時間,單位毫秒
 /** Creates a new instance of CountThread */
 public CountControl() {}
 public synchronized void executeUpdate(){
  Connection conn=null;
  PreparedStatement ps=null;
  try{
   conn = DBUtils.getConnection();
   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();⑴
    //ps.addBatch();⑵
   }
   //int [] counts = ps.executeBatch();⑶
   conn.commit();
  }catch(Exception e){
   e.printStackTrace();
  } finally{
  try{
   if(ps!=null) {
    ps.clearParameters();
ps.close();
ps=null;
  }
 }catch(SQLException e){}
 DBUtils.closeConnection(conn);
 }
}
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");
 }
}
}
//注:如果你的數據庫驅動支持批處理,那么可以將⑵,⑶標記的代碼前的注釋去掉,同時在代碼⑴前加上注釋

  類寫好了,下面是在jsp中如下調用。

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