用CashFilter实现页面级缓存实践

1.mysql在本地localhost的test数据库建person表,暂以字段id,name,password ,表中可输入一行值.

2.建类 DAOUtil

import java.sql.Connection;
import java.sql.DriverManager;

public class DAOUtil {
public DAOUtil() {
}

   public static Connection getConn() {
        Connection conn = null;
        String db_url = "jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=gb2312";
        String db_user = "root";
        String db_password= "admin";
        String db_driver = "com.mysql.jdbc.Driver";

        try {
            Class.forName(db_driver);
            conn = DriverManager.getConnection(db_url, db_user, db_password);
             } catch (Exception ex) {
             ex.printStackTrace();
        }
        return conn;
    }

/**
* dbclose
* 关闭Connection，Statement
* @param conn Connection
* @param stmt Statement
*/
public static void dbclose(Connection conn, Statement stmt) {
       try {
           if (stmt != null)
               stmt.close();
       } catch (Exception e) {
         e.printStackTrace();
       }
       try {
           if (conn != null)
               conn.close();
       } catch (Exception e) {
          e.printStackTrace();
       }
   }

}

3.建类 PersonDAO

import java.util.*;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;

public class PersonDAO {
    static PersonDAO pdao;
    public static PersonDAO getInstance() {
        if (pdao == null) {
            synchronized (PersonDAO.class) {
                pdao = new PersonDAO();
            }
        }
        return pdao;
    }

public PersonDAO() {
super(); }

    public static void main(String[] args) {
          System.out.println("person==="+PersonDAO.getInstance().getPersonInfo());
    }

       private static List getPersonInfo() {
          String name = "";
          String password = "";
          Connection conn = null;
          List list = new java.util.ArrayList();
          Statement stmt = null;
          String sql =
                  "select name,password from person";
          try {
              conn = DAOUtil.getConn();
              stmt = conn.createStatement();
              ResultSet rs = stmt.executeQuery(sql);
              while (rs.next()) {
                  name = (String)rs.getString("name");
                  password = (String)rs.getString("password");
                  list.add(name+","+password);
                 }
          } catch (Exception ex) {
              ex.printStackTrace();
               } finally {
              DAOUtil.dbclose(conn, stmt);
          }
          return list;
      }
}

4.建testCache.jsp,testCache2.jsp

<%@page contentType="text/html; charset=GBK"%>
<%@page import="com.mcsky.dao.PersonDAO" session="false"%>
<%@page import="java.util.List" session="false"%>
<html>
<body bgcolor="#FFFFFF">
test ,hello world!!<p>
<table width="85%" border="1" align="center">
   <tr>
      <td width="8%" height="20"> <div align="center">序号</div></td>
      <td width="12%"><div align="center">名字</div></td>
      <td width="17%"><div align="center">密码 </div></td>
       </tr>
<%
//todo connect mysql server (localhost root/admin) and test(db) person(table)
List list =PersonDAO.getInstance().getPersonInfo();
System.out.println("size==="+list.size());
for(int i=0;i<list.size();i++){
String namePass = (String)list.get(i);
java.util.StringTokenizer st = new java.util.StringTokenizer(namePass,",");
String   name = st.nextToken();
String    pass = st.nextToken();
System.out.println("namePass+++++"+namePass);
%>
<tr>
      <td><div align="center"><%=i+1%></div></td>
      <td> <div align="center"><%=name%></div></td>
      <td><div align="center"><%=pass%></div></td>
      </tr>
    <%
        }
%>
</table>

</body>
</html>

5.把module部署在tomcat的webapp下

5.1 在WEB-INF\lib\log4j-1.2.8.jar,mysql-connector-java-3.0.11-stable-bin.jar,oscache-2.3.2.jar,commons-logging.jar,jgroups-all.jar

5.2 在WEB-INF\classes拷贝cach\etc\下的oscache.tld,oscache.properties

5.3 只对/testCache.jsp缓存

修改WEB-INF\web.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>
<display-name>test</display-name>
<taglib><taglib-uri>oscache</taglib-uri><taglib-location>/WEB-INF/classes/ oscache.tld</taglib-location></taglib>
   <filter>
   <filter-name>CacheFilter</filter-name>
   <filter-class>com.opensymphony.oscache.web.filter.CacheFilter</filter-class>
   </filter>
   <filter-mapping>
   <filter-name>CacheFilter</filter-name>
       <url-pattern>/testCache.jsp</url-pattern>
      </filter-mapping>
</web-app>

启动tomcat,在mysql的person中增加一条记录,发现已对/testCache.jsp页面进行缓存,而/testCache2.jsp页面未缓存,如去掉黑体,则数据表增加一行,testCache.jsp也随之修改

5.4对所有的jsp缓存,

修改WEB-INF\web.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>
<display-name>test</display-name>
      <filter>
        <filter-name>CacheFilter</filter-name>
        <filter-class>com.opensymphony.oscache.web.filter.CacheFilter</filter-class>
          <init-param>
           <param-name>time</param-name>
                    <param-value>60</param-value>
           </init-param>
          <init-param>
          <param-name>scope</param-name>
                     <param-value>session</param-value>
          </init-param>
          </filter>
          <filter-mapping>
          <filter-name>CacheFilter
          </filter-name>
            <url-pattern>*.jsp</url-pattern>
          </filter-mapping>
</web-app>

其中60s,是失效时间,在mysql的person中增加一条记录,发现已对/testCache.jsp,/testCache2.jsp页面进行缓存,页面不变化,60s后页面变化.

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