EnterpriseLibrary+Oralce实现缓存失效并加载数据

本文主要介绍一个简单的解决方案。

主要用到了Caching Application Block+Data Access Application Block+Oracle

原理介绍：给表增加一个触发器，在修改数据时，调用Java存储过程修改一个外部txt文件，让缓存失效，然后重新加载数据。

增加一个测试表wf_sms，表结构如下：

Java存储过程代码：

create or replace and compile java source named say as
import java.io.*;
public class Hello
{
  public static void  say(String str)
  {
    try {
     File aa=new File("C:\\aaa.txt");
         aa.delete();
         aa.createNewFile();
         FileWriter  bb=new FileWriter(aa);
         bb.write(str);
         bb.flush();
         bb.close();
         }
         catch(IOException e)
         {
         
         }
  }
}

增加一个函数调用用Java存储过程：

create or replace function hello(name varchar2) return varchar2
as language java name 'Hello.say(java.lang.String) return java.lang.String';

增加一个触发器：

CREATE OR REPLACE TRIGGER tr_wf_sms
BEFORE INSERT OR DELETE OR UPDATE ON wf_sms
FOR EACH ROW
    
DECLARE
    abc VARCHAR(200);
BEGIN
 
SELECT hello(:NEW.Test2) INTO abc FROM dual;
--execute immediate hello(:NEW.Test2); 
END;

数据库方面的准备工作做完了，现在新建一个c/s程序，界面如下

详细代码如下：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Microsoft.Practices.EnterpriseLibrary.Caching;
using Microsoft.Practices.EnterpriseLibrary.Caching.Expirations;
using Microsoft.Practices.EnterpriseLibrary.Common;
using Microsoft.Practices.EnterpriseLibrary.Data;
using System.Data.Common;

namespace EnterpriseLibraryTest1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        ICacheManager cacheManager;
        Database db = DatabaseFactory.CreateDatabase();
        DataTable _table;        

        /// <summary>
        /// 加载缓存
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
            FileDependency _fileDep = new FileDependency("c:\\aaa.txt");
            cacheManager.Add(_table.Rows[0]["test1"].ToString(), _table.Rows[0]["test2"].ToString(), CacheItemPriority.Normal, null, _fileDep);//加入缓存
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            cacheManager = CacheFactory.GetCacheManager();//实例化ICachemanager
            string sql = "select * from wf_sms";
            DbCommand dc = db.GetSqlStringCommand(sql);
            _table = db.ExecuteDataSet(dc).Tables[0];
        }
        /// <summary>
        /// 获取缓存数据
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button2_Click(object sender, EventArgs e)
        {
            if (cacheManager.GetData("aaa") == null)
            {
                FileDependency _fileDep1 = new FileDependency("c:\\aaa.txt");
                cacheManager.Remove("aaa");
                string sql = "select test2 from wf_sms where test1='aaa'";
                DbCommand dc = db.GetSqlStringCommand(sql);
                string str = (string)db.ExecuteScalar(dc);
                cacheManager.Add("aaa", str, CacheItemPriority.Normal, null, _fileDep1);
            }
            this.richTextBox1.Text = cacheManager.GetData("aaa").ToString();
        }
        /// <summary>
        /// 修改数据
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button3_Click(object sender, EventArgs e)
        {
            string sql = "update wf_sms set test2='" + Guid.NewGuid().ToString() + "' where test1='aaa'";
            db.ExecuteNonQuery(CommandType.Text, sql);
        }
    }
}