需求:有一个标(理解成抢红包也行,accountbalance预赋值1000元),大家可以抢购,每个用户抢购成功后,更新最后标的总数,在并发情况下,使用redis的乐观锁,保证更新标总值正确性,先往redis放一个标的金额:
set accountBalance "1000"
实现方式如下:
pom.xml
4.0.0 mybatisPage page 1.0-SNAPSHOT war PageHelperSample http://git.oschina.net/free/Mybatis-Sample UTF-8 jstl jstl 1.1.2 taglibs standard 1.1.2 commons-pool commons-pool 1.6 org.slf4j slf4j-log4j12 1.7.5 org.slf4j slf4j-api 1.7.5 com.alibaba fastjson 1.2.5 com.alibaba fastjson 1.2.4 javax.servlet servlet-api 2.5 provided javax.servlet.jsp jsp-api 2.1 provided taglibs standard 1.1.2 javax.servlet jstl 1.2 com.github.pagehelper pagehelper 3.7.4 com.github.jsqlparser jsqlparser 0.9.1 junit junit 4.11 test log4j log4j 1.2.17 org.mybatis mybatis 3.2.5 org.apache.commons commons-lang3 3.1 mysql mysql-connector-java 5.1.35 redis.clients jedis 2.1.0 jar org.apache.maven.plugins maven-compiler-plugin 1.6 1.6 utf-8 org.mortbay.jetty jetty-maven-plugin 8.0.0.M3
web.xml
index.jsp bid com.heli.mybatis.page.servlet.ReidsMatchServlet bid /bid list com.heli.mybatis.page.servlet.ReidsMatchListServlet list /list
servlet
package com.heli.mybatis.page.servlet;
import java.io.IOException;
import java.util.List;
import java.util.Random;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.lang3.StringUtils;
import com.commnon.RedisAPI;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.Transaction;
public class ReidsMatchServlet extends HttpServlet {
public static JedisPool pool = RedisAPI.getPool();
// RedisAPI.set("accountBalance", "999999999");// 标还剩999999999块钱
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Jedis jedis = pool.getResource();
long start = System.currentTimeMillis();
int flag = 0;
try {
flag = bid(request, response, jedis);
} catch (Exception e) {
e.printStackTrace();
response.getWriter().write("fail buy");
} finally {
pool.returnBrokenResource(jedis);
RedisAPI.returnResource(pool, jedis);
}
if (flag == 1) {
response.getWriter().write("success buy");
} else if (flag == 2) {
response.getWriter().write("have buy");
} else if (flag == 0) {
response.getWriter().write("bid is zero ,you can not buy");
}else{
response.getWriter().write("fail buy");
}
long end = System.currentTimeMillis();
System.out.println("--------------------------------------------请求耗时:" + (end - start) + "毫秒");
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
private int bid(HttpServletRequest request, HttpServletResponse response, Jedis jedis) throws Exception {
int flag = 0;// 1,成功,2已经购买,3已经没钱了,其他異常
// 每个请求对应一个userId
int userId = new Random().nextInt(999999);
// 观察 总标值,每人抢购一元
while ("OK".equals(jedis.watch("accountBalance"))) {
// 判断是否购买过
Boolean isBuy = RedisAPI.sismember("userIdSet", userId + "");
if (isBuy) {
flag = 2;
return flag;
}
//投资额
int r = 1;// new Random().nextInt(2);
int lastAccount = 0;
String balance = RedisAPI.get("accountBalance");
if (StringUtils.isNotBlank(balance)) {
lastAccount = Integer.valueOf(balance) - r;
}
if (lastAccount < 0) {
flag = 3;
break;
}
Transaction tx = jedis.multi();
tx.set("accountBalance", lastAccount + "");
Listpackage com.heli.mybatis.page.servlet;
import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.commnon.RedisAPI;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
public class ReidsMatchListServlet extends HttpServlet {
public static JedisPool pool= RedisAPI.getPool();;
public static Jedis jedis;
static {
jedis = pool.getResource();
}
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
list(request, response);
try {
response.sendRedirect("list.jsp");
} catch (IOException e) {
e.printStackTrace();
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
private void list(HttpServletRequest request, HttpServletResponse response) {
Set set = jedis.smembers("userIdSet");
Iterator ite = set.iterator();
System.out.println("中标名单-------------------------");
int i = 0;
Map map = new HashMap();
while (ite.hasNext()) {
i++;
Object obj1 = ite.next();
System.out.println("第" + i + "名:" + obj1);
map.put("第" + i + "名:", obj1 + "");
}
request.getSession().setAttribute("user", map);
System.out.println("中标名单-------------------------");
}
} 工具类
package com.commnon;
import java.util.ResourceBundle;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;
/**
* Redis操作接口
*
* @author 林计钦
* @version 1.0 2013-6-14 上午08:54:14
*/
public class RedisAPI {
private static JedisPool pool = null;
private static ThreadLocal poolThreadLocal = new ThreadLocal();
/**
* 构建redis连接池
*
* @param ip
* @param port
* @return JedisPool
*/
public static JedisPool getPool() {
if (pool == null) {
ResourceBundle bundle = ResourceBundle.getBundle("redis");
if (bundle == null) {
throw new IllegalArgumentException(
"[redis.properties] is not found!");
}
JedisPoolConfig config = new JedisPoolConfig();
config.setMaxActive(Integer.valueOf(bundle
.getString("redis.pool.maxActive")));
config.setMaxIdle(Integer.valueOf(bundle
.getString("redis.pool.maxIdle")));
config.setMaxWait(Long.valueOf(bundle.getString("redis.pool.maxWait")));
config.setTestOnBorrow(Boolean.valueOf(bundle
.getString("redis.pool.testOnBorrow")));
config.setTestOnReturn(Boolean.valueOf(bundle
.getString("redis.pool.testOnReturn")));
pool = new JedisPool(config, bundle.getString("redis.ip"),
Integer.valueOf(bundle.getString("redis.port")));
}
return pool;
}
public static JedisPool getConnection() {
// ②如果poolThreadLocal没有本线程对应的JedisPool创建一个新的JedisPool,将其保存到线程本地变量中。
if (poolThreadLocal.get() == null) {
pool = RedisAPI.getPool();
poolThreadLocal.set(pool);
return pool;
} else {
return poolThreadLocal.get();// ③直接返回线程本地变量
}
}
/**
* 返还到连接池
*
* @param pool
* @param redis
*/
public static void returnResource(JedisPool pool, Jedis redis) {
if (redis != null) {
pool.returnResource(redis);
}
}
/**
* 获取数据
*
* @param key
* @return
*/
public static String get(String key) {
String value = null;
JedisPool pool = null;
Jedis jedis = null;
try {
pool = getPool();
jedis = pool.getResource();
value = jedis.get(key);
} catch (Exception e) {
e.printStackTrace();
} finally {
// 释放redis对象
pool.returnBrokenResource(jedis);
// 返还到连接池
returnResource(pool, jedis);
}
return value;
}
/**
* 赋值数据
*
* @param key
* @return
*/
public static String set(String key, String value) {
String result = null;
JedisPool pool = null;
Jedis jedis = null;
try {
pool = getPool();
jedis = pool.getResource();
result = jedis.set(key, value);
} catch (Exception e) {
e.printStackTrace();
} finally {
// 释放redis对象
pool.returnBrokenResource(jedis);
// 返还到连接池
returnResource(pool, jedis);
}
return result;
}
/**
* 赋值数据
*
* @param key
* @return
*/
public static Long sadd(String key, String value) {
Long result = null;
JedisPool pool = null;
Jedis jedis = null;
try {
pool = getPool();
jedis = pool.getResource();
result = jedis.sadd(key, value);
} catch (Exception e) {
e.printStackTrace();
} finally {
// 释放redis对象
pool.returnBrokenResource(jedis);
// 返还到连接池
returnResource(pool, jedis);
}
return result;
}
/**
* 判断set中是否有值
*
* @param key
* @return
*/
public static Boolean sismember(String key, String member) {
Boolean result = null;
JedisPool pool = null;
Jedis jedis = null;
try {
pool = getPool();
jedis = pool.getResource();
result = jedis.sismember(key, member);
} catch (Exception e) {
e.printStackTrace();
} finally {
// 释放redis对象
pool.returnBrokenResource(jedis);
// 返还到连接池
returnResource(pool, jedis);
}
return result;
}
} redis.properties
#\u6700\u5927\u5206\u914d\u7684\u5bf9\u8c61\u6570 redis.pool.maxActive=1024 #\u6700\u5927\u80fd\u591f\u4fdd\u6301idel\u72b6\u6001\u7684\u5bf9\u8c61\u6570 redis.pool.maxIdle=200 #\u5f53\u6c60\u5185\u6ca1\u6709\u8fd4\u56de\u5bf9\u8c61\u65f6\uff0c\u6700\u5927\u7b49\u5f85\u65f6\u95f4 redis.pool.maxWait=1000 #\u5f53\u8c03\u7528borrow Object\u65b9\u6cd5\u65f6\uff0c\u662f\u5426\u8fdb\u884c\u6709\u6548\u6027\u68c0\u67e5 redis.pool.testOnBorrow=true #\u5f53\u8c03\u7528return Object\u65b9\u6cd5\u65f6\uff0c\u662f\u5426\u8fdb\u884c\u6709\u6548\u6027\u68c0\u67e5 redis.pool.testOnReturn=true #IP redis.ip=127.0.0.1 #Port redis.port=6379
bid.jsp
<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>抢标秒杀
list.jsp
<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>抢标秒杀 <% java.util.MapmapBean = (java.util.Map ) request.getSession() .getAttribute("user"); %>










