java缓存技术memcached实例

1 下载memcached-1.2.1-win32.zip 并且解压.

2 新建web project项目名字自己取,然后导入必要的包,alisoft-xplatform-asf-cache-2.5.1.jar,commons-logging-1.0.3.jar,log4j-1.2.13.jar

3 新建类 user.java

package bean;

import java.io.Serializable;

public class User implements Serializable{

    /**
     * 序列号
     */
    private static final long serialVersionUID = -3896605600471191953L;
    private int uid;
    private String uname;
    private String upass;

    public int getUid() {
       return uid;
    }
    public void setUid(int uid) {
       this.uid = uid;
    }
    public String getUname() {
       return uname;
    }
    public void setUname(String uname) {
       this.uname = uname;
    }
    public String getUpass() {
       return upass;
    }
    public void setUpass(String upass) {
       this.upass = upass;
    }

}

4 新建 JdbcConnector.java

package util;

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

public class JdbcConnector {
// 定义数据库连接常量
    private final static String DRIVER = "com.mysql.jdbc.Driver";
    private final static String URL = "jdbc:mysql://192.168.1.13:3306/test";
    private final static String DBNAME = "root";
    private final static String DBPASS = "123456";

    /**
     * 得到数据库连接
     * @return
     * @throws ClassNotFoundException
     * @throws SQLException
     */
    public Connection getConn()throws ClassNotFoundException,SQLException {
       // 加载驱动
       Class.forName(DRIVER);
       // 通过DriverManager对象得到连接
       Connection conn = DriverManager.getConnection(URL,DBNAME,DBPASS);
       // 返回数据库连接
       return conn;
    }
}

5 新建 UserDao.java

package util;

import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import bean.User;

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.PreparedStatement;
import com.mysql.jdbc.ResultSet;

public class UserDao extends JdbcConnector {
    // 定义全局变量
    Connection conn = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;

    /**
     * 根据Id查询用户
     * @param uid
     * @return
     */
    public User getUserById(int uid) {
       // 创建User对象
       User user = null;
       // 创建SQL语句
       String sql = "select * from user where uid=?";

       try {
           // 获得数据库连接
           conn = (Connection) this.getConn();
           // 通过Connection对象创建PrepareStatement对象
           pstmt = (PreparedStatement) conn.prepareStatement(sql);
           // 设置SQL语句的参数
           pstmt.setInt(2, uid);
           // 执行查询，将查询结果赋给ResultSet对象
           rs = (ResultSet) pstmt.executeQuery();
           // 遍历指针
           while (rs.next())
           {
              user = new User();
              user.setUid(rs.getInt("uid"));
              user.setUname(rs.getString("uname"));
              user.setUpass(rs.getString("upass"));
           }
       } catch (ClassNotFoundException e) {
           e.printStackTrace();
       } catch (SQLException e) {
           e.printStackTrace();
       }
       return user;
    }

    /**
     * 查询所有用户
     * @return
     */
    @SuppressWarnings("unchecked")
    public List getUserList() {
       // 创建ArrayList对象
       List userList = new ArrayList();

       // 创建SQL对象
       String sql = "select * from user";

       try {
           conn = (Connection) this.getConn();
           pstmt = (PreparedStatement) conn.prepareStatement(sql);
           rs = (ResultSet) pstmt.executeQuery();
           while (rs.next())
           {
              User user = new User();
              user.setUid(rs.getInt("uid"));
              user.setUname(rs.getString("uname"));
              user.setUpass(rs.getString("upass"));

              userList.add(user);
           }
       } catch (ClassNotFoundException e) {
           e.printStackTrace();
       } catch (SQLException e) {
           e.printStackTrace();
       }
       return userList;
    }

}

6 新建 MemcachedManager.java

package memcachedTest;

import java.util.Date;
import java.util.List;

import util.UserDao;
import bean.User;

import com.alisoft.xplatform.asf.cache.memcached.client.MemCachedClient;
import com.alisoft.xplatform.asf.cache.memcached.client.SockIOPool;

public class MemcachedManager {

   // 创建MemCachedClient全局对象
    private static MemCachedClient mcc = new MemCachedClient();

    static {
       // 创建服务器列表及其权重
       String[] servers = {"127.0.0.1:11211"};
       Integer[] weights = {3};

       // 创建Socket连接池对象
       SockIOPool pool = SockIOPool.getInstance();

       // 设置服务器信息
       pool.setServers(servers);
       pool.setWeights(weights);
       pool.setFailover(true);

       // 设置初始连接数、最小和最大连接数以及最大处理时间
       pool.setInitConn(5);
       pool.setMinConn(5);
       pool.setMaxConn(250);
       pool.setMaxIdle(1000*60*60*6);

       // 设置主线程睡眠时间
       pool.setMaintSleep(30);

       // 设置TCP参数、连接超时等
       pool.setNagle(false);
       pool.setSocketTO(3000);
       pool.setSocketConnectTO(0);
       pool.setAliveCheck(true);

       // 初始化连接池
       pool.initialize();

       // 压缩设置，超过指定大小（单位为K）的数据都会被压缩
       mcc.setCompressEnable(true);
       mcc.setCompressThreshold(64 * 1024);
    }

    /**
     * 无参构造
     */
    protected MemcachedManager (){

    }

    // 受保护的对象
    protected static MemcachedManager instance = new MemcachedManager();

    /**
     * 为受保护的对象提供一个公共的访问方法
     */
    public static MemcachedManager getInstance () {
       return instance;
    }

    /**
     * 添加对象到缓存中，构成方法重载
     * @param key
     * @param value
     * @return
     */
    public boolean add(String key,Object value) {
       return mcc.add(key, value);
    }
    public boolean add (String key,Object value,Date expiry) {
       return mcc.add(key, value,expiry);
    }

    public boolean replace (String key,Object value) {
       return mcc.replace(key, value);
    }

    public boolean replace (String key,Object value,Date expiry)
    {
       return mcc.replace(key, value, expiry);
    }

    /**
     * 根据指定的关键字获取对象
     */
    public Object get(String key) {
       return mcc.get(key);
    }



    /**
     * 利用MemCached测试将单个对象存入缓存，并从缓存中取出
     */
// public static void main(String[] args) {
//      // 得到MemcachedManager实例
//     MemcachedManager cache = MemcachedManager.getInstance();
//
//     // 创建UserDao对象
//     UserDao userDao = new UserDao();
//     // 查询单个User对象
//     User user = userDao.getUserById(4);
//
//     // 将User对象添加到缓存中
//     cache.add("user", user.getUname());
//
//     // 将User对象从缓存中取出来
//     String uname = (String)cache.get("user");
//
//     System.out.println("从缓存中取出的对象为：" + uname);
// }



    /**
     * 利用MemCached对象将集合存入缓存，并从缓存中取出
     */
    @SuppressWarnings({ "unchecked", "rawtypes" })
    public static void main(String[] args) {
       // 得到MemcachedManager实例
       MemcachedManager cache = MemcachedManager.getInstance();

       // 创建UserDao对象
       UserDao userDao = new UserDao();
       // 得到集合对象
       List userList = userDao.getUserList();

       // 创建User对象
       User user = null;
       for (int i=0; i<userList.size(); i++)
       {
           // 循环遍历集合对象
           user = (User)userList.get(i);
           user.getUid();
           user.getUname();
           user.getUpass();

           // 将集合对象存入缓存中
           cache.add("userList" + i,user.getUname());

           // 将集合从缓存中取出
           String uname = (String)cache.get("userList"+i);

           System.out.println("从缓存中取得的集合为：" + uname);
       }
    }

}

结果从控制台输出:

从缓存中取得的集合为：uname
从缓存中取得的集合为：uname1
从缓存中取得的集合为：uname2
从缓存中取得的集合为：uname3

java缓存技术memcached实例

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