redis optimistic lock practice flash sale

Demand: There is a bid (it can be understood as grabbing red envelopes, the accountBalance is pre-assigned 1,000 yuan), and everyone can snap up it. After each user succeeds in snapping up, the total number of the last bid will be updated. In the case of concurrency, redis's optimistic lock is used to ensure updates. To check the correctness of the total bid value, first put a bid amount into redis:

set accountBalance "1000"

The implementation method is as follows:

pom. bid.jsp

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>mybatisPage</groupId>
	<artifactId>page</artifactId>
	<version>1.0-SNAPSHOT</version>
	<packaging>war</packaging>

	<name>PageHelperSample</name>
	<url>http://git.oschina.net/free/Mybatis-Sample</url>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
	</properties>

	<dependencies>
		<!-- jstl -->
		<dependency>
			<groupId>jstl</groupId>
			<artifactId>jstl</artifactId>
			<version>1.1.2</version>
		</dependency>
		<dependency>
			<groupId>taglibs</groupId>
			<artifactId>standard</artifactId>
			<version>1.1.2</version>
		</dependency>
		<!-- jstl -->
		<dependency>
			<groupId>commons-pool</groupId>
			<artifactId>commons-pool</artifactId>
			<version>1.6</version>
		</dependency>

		<!-- log mybatis sql -->
		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-log4j12</artifactId>
			<version>1.7.5</version>
		</dependency>
		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-api</artifactId>
			<version>1.7.5</version>
		</dependency>
		<!-- log mybatis sql -->

		<!-- fastjson -->
		<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>fastjson</artifactId>
			<version>1.2.5</version>
		</dependency>
		<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>fastjson</artifactId>
			<version>1.2.4</version>
		</dependency>
		<!-- web -->
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>servlet-api</artifactId>
			<version>2.5</version>
			<scope>provided</scope>
		</dependency>
		<dependency>
			<groupId>javax.servlet.jsp</groupId>
			<artifactId>jsp-api</artifactId>
			<version>2.1</version>
			<scope>provided</scope>
		</dependency>
		<dependency>
			<groupId>taglibs</groupId>
			<artifactId>standard</artifactId>
			<version>1.1.2</version>
		</dependency>
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>jstl</artifactId>
			<version>1.2</version>
		</dependency>

		<dependency>
			<groupId>com.github.pagehelper</groupId>
			<artifactId>pagehelper</artifactId>
			<version>3.7.4</version>
		</dependency>
		<dependency>
			<groupId>com.github.jsqlparser</groupId>
			<artifactId>jsqlparser</artifactId>
			<version>0.9.1</version>
		</dependency>

		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>4.11</version>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>log4j</groupId>
			<artifactId>log4j</artifactId>
			<version>1.2.17</version>
		</dependency>
		<dependency>
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis</artifactId>
			<version>3.2.5</version>
		</dependency>
		<!-- util -->
		<dependency>
			<groupId>org.apache.commons</groupId>
			<artifactId>commons-lang3</artifactId>
			<version>3.1</version>
		</dependency>
		<!-- mysql -->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>5.1.35</version>
		</dependency>
		<!-- redis -->
		<dependency>
			<groupId>redis.clients</groupId>
			<artifactId>jedis</artifactId>
			<version>2.1.0</version>
			<type>jar</type>
		</dependency>
	</dependencies>
	<build>
		<plugins>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-compiler-plugin</artifactId>
				<configuration>
					<source>1.6</source>
					<target>1.6</target>
					<encoding>utf-8</encoding>
				</configuration>
			</plugin>
			<plugin>
				<groupId>org.mortbay.jetty</groupId>
				<artifactId>jetty-maven-plugin</artifactId>
				<version>8.0.0.M3</version>
			</plugin>
		</plugins>
	</build></project>

list.jsp

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://java.sun.com/xml/ns/javaee"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
	version="3.0">
	<welcome-file-list>
		<welcome-file>index.jsp</welcome-file>
	</welcome-file-list>
	
	<servlet>
		<servlet-name>bid</servlet-name>
		<servlet-class>com.heli.mybatis.page.servlet.ReidsMatchServlet</servlet-class>
	</servlet>
	<servlet-mapping>
		<servlet-name>bid</servlet-name>
		<url-pattern>/bid</url-pattern>
	</servlet-mapping>
	<servlet>
		<servlet-name>list</servlet-name>
		<servlet-class>com.heli.mybatis.page.servlet.ReidsMatchListServlet</servlet-class>
	</servlet>
	<servlet-mapping>
		<servlet-name>list</servlet-name>
		<url-pattern>/list</url-pattern>
	</servlet-mapping></web-app>