浅谈mybatis 乐观锁实现,解决并发问题

drop table if exists account_wallet;
 
/*==============================================================*/
/* Table: account_wallet          */
/*==============================================================*/
create table account_wallet
(
 id     int not null comment '用户钱包主键',
 user_open_id   varchar(64) comment '用户中心的用户唯一编号',
 user_amount   decimal(10,5),
 create_time   datetime,
 update_time   datetime,
 pay_password   varchar(64),
 is_open    int comment '0:代表未开启支付密码，1:代表开发支付密码',
 check_key   varchar(64) comment '平台进行用户余额更改时，首先效验key值，否则无法进行用户余额更改操作',
 version    int comment '基于mysql乐观锁，解决并发访问'
 primary key (id)
);

 public AccountWallet selectByOpenId(String openId) {
 // TODO Auto-generated method stub
 return accountWalletMapper.selectByOpenId(openId);
 }
 
 public int updateAccountWallet(AccountWallet record) {
 // TODO Auto-generated method stub
 return accountWalletMapper.updateAccountWallet(record);
 }

 <!--通过用户唯一编号，查询用户钱包相关的信息 -->
 <select id="selectByOpenId" resultMap="BaseResultMap" parameterType="java.lang.String">
 select 
 <include refid="Base_Column_List" />
 from account_wallet
 where user_open_id = #{openId,jdbcType=VARCHAR}
 </select>
 <!--用户钱包数据更改 ，通过乐观锁(version机制)实现 -->
 <update id="updateAccountWallet" parameterType="com.settlement.model.AccountWallet">
   <![CDATA[
   update account_wallet set user_amount = #{userAmount,jdbcType=DECIMAL}, version = version + 1 where id =#{id,jdbcType=INTEGER} and version = #{version,jdbcType=INTEGER} 
   ]]> 
 </update>

package com.settlement.controller;
 
import java.math.BigDecimal;
import javax.servlet.http.HttpServletRequest;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import com.settlement.commons.base.BaseController;
import com.settlement.model.AccountWallet;
import com.settlement.service.AccountWalletService;
import com.taobao.api.internal.util.StringUtils;
 
/**
 * 用户钱包Controller
 * 
 * @author zzg
 * @date 2017-02-10
 */
 
@Controller
@RequestMapping(value = "/wallet")
public class WalletController extends BaseController {
 
	@Autowired
	private AccountWalletService accountWalletService;
 
	/**
	 * 针对业务系统高并发-----修改用户钱包数据余额，采用乐观锁
	 * 
	 * @return
	 */
	@RequestMapping(value = "/walleroptimisticlock.action", method = RequestMethod.POST)
	@ResponseBody
	public String walleroptimisticlock(HttpServletRequest request) {
 
		String result = "";
 
		try {
			String openId = request.getParameter("openId") == null ? null
					: request.getParameter("openId").trim(); // 用户唯一编号
			String openType = request.getParameter("openType") == null ? null
					: request.getParameter("openType").trim(); // 1:代表增加，2：代表减少
			String amount = request.getParameter("amount") == null ? null
					: request.getParameter("amount").trim(); // 金额
 
			if (StringUtils.isEmpty(openId)) {
				return "openId is null";
			}
			if (StringUtils.isEmpty(openType)) {
				return "openType is null";
			}
			if (StringUtils.isEmpty(amount)) {
				return "amount is null";
			}
			AccountWallet wallet = accountWalletService.selectByOpenId(openId);
 
			// 用户操作金额
			BigDecimal cash = BigDecimal.valueOf(Double.parseDouble(amount));
			cash.doubleValue();
			cash.floatValue();
			if (Integer.parseInt(openType) == 1) {
				wallet.setUserAmount(wallet.getUserAmount().add(cash));
			} else if (Integer.parseInt(openType) == 2) {
				wallet.setUserAmount(wallet.getUserAmount().subtract(cash));
			}
 
			int target = accountWalletService.updateAccountWallet(wallet);
			System.out.println("修改用户金额是否：" + (target == 1 ? "成功" : "失败"));
 
		} catch (Exception e) {
			result = e.getMessage();
			return result;
		}
 
		return "success";
	}
 
}

package com.settlement.concurrent; 
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.CountDownLatch; 
import com.settlement.commons.utils.HttpRequest; 
 
/**
 * 模拟用户的并发请求，检测用户乐观锁的性能问题
 * 
 * @author zzg
 * @date 2017-02-10
 */
public class ConcurrentTest {
	final static SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 
	public static void main(String[] args){
		CountDownLatch latch=new CountDownLatch(1);//模拟5人并发请求，用户钱包
		
		for(int i=0;i<5;i++){//模拟5个用户
			AnalogUser analogUser = new AnalogUser("user"+i,"58899dcd-46b0-4b16-82df-bdfd0d953bfb","1","20.024",latch);
			analogUser.start();
		}
		latch.countDown();//计数器減一 所有线程释放 并发访问。
		System.out.println("所有模拟请求结束 at "+sdf.format(new Date())); 		
	}	
	static class AnalogUser extends Thread{
		String workerName;//模拟用户姓名
		String openId;
		String openType;
		String amount;
		CountDownLatch latch;
		
		public AnalogUser(String workerName, String openId, String openType, String amount,
				CountDownLatch latch) {
			super();
			this.workerName = workerName;
			this.openId = openId;
			this.openType = openType;
			this.amount = amount;
			this.latch = latch;
		}
		@Override
		public void run() {
			// TODO Auto-generated method stub
			try { 
				latch.await(); //一直阻塞当前线程，直到计时器的值为0 
	  } catch (InterruptedException e) { 
	   e.printStackTrace(); 
	  } 			
			post();//发送post 请求 			
		} 
		
		public void post(){
			String result = "";
			System.out.println("模拟用户： "+workerName+" 开始发送模拟请求 at "+sdf.format(new Date())); 
			result = HttpRequest.sendPost("http://localhost:8080/Settlement/wallet/walleroptimisticlock.action", "openId="+openId+"&openType="+openType+"&amount="+amount);
			System.out.println("操作结果："+result);
			System.out.println("模拟用户： "+workerName+" 模拟请求结束 at "+sdf.format(new Date())); 
			
		}			
	}
}

package com.wuyd.mybatispulsdemo;

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.generator.AutoGenerator;
import com.baomidou.mybatisplus.generator.config.*;
import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy;

/**
 * @author wuyd
 * 创建时间：2019/10/8 11:17
 */
public class CodeGenerator {
 public static void main(String[] args) {
  AutoGenerator mpg = new AutoGenerator();

  //全局配置
  GlobalConfig gc = new GlobalConfig();
  gc.setOutputDir(System.getProperty("user.dir")+"/src/main/java");
  gc.setFileOverride(true);
  //不需要ActiveRecord特性的请改为false
  gc.setActiveRecord(true);
  gc.setSwagger2(true);
  gc.setAuthor("wuyd");

  //自定义文件命名，注意%s 会自动填充表实体属性
  gc.setControllerName("%sController");
  gc.setServiceName("%sService");
  gc.setServiceImplName("%sServiceImpl");
  gc.setEntityName("%sEntity");
  gc.setMapperName("%sMapper");

  mpg.setGlobalConfig(gc);

  //数据源配置
  DataSourceConfig dsc = new DataSourceConfig();
  dsc.setDbType(DbType.MYSQL);
  dsc.setDriverName("com.mysql.jdbc.Driver");
  dsc.setUsername("xxx");
  dsc.setPassword("xxx");
  dsc.setUrl("jdbc:mysql://xxx.xxx.xxx.xxx:3306/xxxxx?useUnicode=true&useSSL=false&characterEncoding=utf8");
  mpg.setDataSource(dsc);

  //策略配置
  StrategyConfig strategy = new StrategyConfig();
  //此处可以修改您的表前缀
  strategy.setTablePrefix(new String[]{});
  //表名生成策略
  strategy.setNaming(NamingStrategy.underline_to_camel);
  strategy.setColumnNaming(NamingStrategy.underline_to_camel);
  //需要生成的表
  strategy.setInclude(new String[]{"knapsacks","knapsacks_kind","knapsacks_prop","knapsacks_recharge_card"});

  strategy.setSuperServiceClass(null);
  strategy.setSuperServiceImplClass(null);

  strategy.setSuperMapperClass(null);
  strategy.setControllerMappingHyphenStyle(true);

  strategy.setEntityLombokModel(true);
  strategy.setEntitySerialVersionUID(true);
  strategy.setEntityTableFieldAnnotationEnable(true);

  mpg.setStrategy(strategy);
  // 配置模板
  TemplateConfig templateConfig = new TemplateConfig();
  templateConfig.setXml(null);
  mpg.setTemplate(templateConfig);

  //包配置
  PackageConfig pc = new PackageConfig();
  pc.setParent("com.wuyd.mybatispulsdemo");
  pc.setController("controller");
  pc.setService("service");
  pc.setServiceImpl("service.impl");
  pc.setMapper("mapper");
  pc.setEntity("entity");
  mpg.setPackageInfo(pc);

  //执行生成
  mpg.execute();
 }
}

  <dependency>
   <groupId>com.baomidou</groupId>
   <artifactId>mybatis-plus-generator</artifactId>
   <version>3.2.0</version>
  </dependency>
  <!-- ORM 选一款 -->
  <dependency>
   <groupId>com.baomidou</groupId>
   <artifactId>mybatis-plus-boot-starter</artifactId>
   <version>${mybatis-plus-boot-starter.version}</version>
  </dependency>
  <!-- Mysql驱动 注意版本！-->
  <dependency>
   <groupId>mysql</groupId>
   <artifactId>mysql-connector-java</artifactId>
   <version>${mysql-connector.version}</version>
  </dependency>
  <dependency>
   <groupId>org.apache.velocity</groupId>
   <artifactId>velocity-engine-core</artifactId>
   <version>2.1</version>
  </dependency>