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Java分布式锁

一、基于ReentrantLock锁解决超卖问题(单体)

1.1、重要代码

package com.example.distributedemo.service;
import com.example.distributedemo.dao.OrderItemMapper;
import com.example.distributedemo.dao.OrderInfoMapper;
import com.example.distributedemo.dao.ProductMapper;
import com.example.distributedemo.model.orderInfo;
import com.example.distributedemo.model.OrderItem;
import com.example.distributedemo.model.Product;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.TransactionDefinition;
import org.springframework.transaction.TransactionStatus;
import javax.annotation.Resource;
import java.math.BigDecimal;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
@Service
@Slf4j
public class OrderService { 

@Resource
private OrderInfoMapper orderMapper;
@Resource
private OrderItemMapper orderItemMapper;
@Resource
private ProductMapper productMapper;
//购买商品id
private Integer  purchaseProductId = 1;
//购买商品数量
private int purchaseProductNum = 1;
@Autowired
private PlatformTransactionManager platformTransactionManager;
@Autowired
private TransactionDefinition transactionDefinition;
private Lock lock = new ReentrantLock();
public Integer createOrder() throws Exception{ 

Product product = null;
lock.lock();
try { 

// 根据事务定义TransactionDefinition，获取事务
TransactionStatus transaction1 = platformTransactionManager.getTransaction(transactionDefinition);
product = productMapper.selectByPrimaryKey(purchaseProductId);
if (product==null){ 

// 回滚事务
platformTransactionManager.rollback(transaction1);
throw new Exception("购买商品："+purchaseProductId+"不存在");
}
// 商品当前库存
Integer currentCount = product.getCount();
System.out.println(Thread.currentThread().getName()+"库存数："+currentCount);
// 校验库存
if (purchaseProductNum > currentCount){ 

// 回滚事务
platformTransactionManager.rollback(transaction1);
throw new Exception("商品"+purchaseProductId+"仅剩"+currentCount+"件，无法购买");
}
Product product1 = new Product();
product1.setId(purchaseProductId);
product1.setCount(0);
productMapper.updateByPrimaryKeySelective(product1);
// 提交事务
platformTransactionManager.commit(transaction1);
}finally { 

lock.unlock();
}
TransactionStatus transaction = platformTransactionManager.getTransaction(transactionDefinition);
orderInfo order = new orderInfo();
order.setId(1);
order.setOrderName(product.getName());
order.setAmount(product.getPrice().multiply(new BigDecimal(purchaseProductNum)));
order.setOrderStatus(1);//待处理
orderMapper.insertSelective(order);
OrderItem orderItem = new OrderItem();
orderItem.setId(1);
orderItem.setOrderId(order.getId());
orderItem.setProductId(product.getId());
orderItemMapper.insertSelective(orderItem);
platformTransactionManager.commit(transaction);
return order.getId();
}
}

1.2、测试代码

package com.example;
import com.example.distributedemo.DistributeDemoApplication;
import com.example.distributedemo.service.OrderService;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
@RunWith(SpringRunner.class)
@SpringBootTest(classes = DistributeDemoApplication.class)
public class DistributeDemoApplicationTests { 

@Autowired
private OrderService orderService;
@Test
public void concurrentOrder() throws InterruptedException { 

CountDownLatch cdl = new CountDownLatch(5);
CyclicBarrier cyclicBarrier = new CyclicBarrier(5);
ExecutorService es = Executors.newFixedThreadPool(5);
for (int i =0;i<5;i++){ 

es.execute(()->{ 

try { 

cyclicBarrier.await();
Integer orderId = orderService.createOrder();
System.out.println("订单id："+orderId);
} catch (Exception e) { 

e.printStackTrace();
}finally { 

cdl.countDown();
}
});
}
cdl.await();
es.shutdown();
}
}

二、 基于数据库的分布式锁（分布式）

2.1、重要代码

package com.example.distributedemo.controller;
import com.example.distributedemo.dao.DistributeLockMapper;
import com.example.distributedemo.model.DistributeLock;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
/**
* @author zhuzhaoman
* @date 2020/5/2 14:56
* @description  基于数据库的分布式锁
*/
@Slf4j
@RestController
public class DemoController { 

@Resource
private DistributeLockMapper distributeLockMapper;
@RequestMapping("/singleLock")
@Transactional(rollbackFor = Exception.class)
public String singleLock() throws Exception { 

log.info("已经进入方法！");
DistributeLock distributeLock = distributeLockMapper.selectDistributeLock("demo");
if (distributeLock == null){ 

throw new Exception("分布式锁找不到");
}
log.info("已经进入了锁！");
Thread.sleep(30000);
return "我已经执行完成！";
}
}

2.2、重要sql语句

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.distributedemo.dao.DistributeLockMapper">
<resultMap id="BaseResultMap" type="com.example.distributedemo.model.DistributeLock">
<!--
WARNING - @mbg.generated
-->
<id column="id" jdbcType="INTEGER" property="id" />
<result column="business_code" jdbcType="VARCHAR" property="businessCode" />
<result column="business_name" jdbcType="VARCHAR" property="businessName" />
</resultMap>
<select id="selectDistributeLock" resultType="com.example.distributedemo.model.DistributeLock">
select *from distribute_lock
where business_code = #{businessCode}
for update
</select>
</mapper>

2.3、测试

http://localhost:8081/singleLock
http://localhost:8082/singleLock

三、基于redis分布式锁

3.1、重要代码

package com.example.distributedemo.controller;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.connection.RedisStringCommands;
import org.springframework.data.redis.core.RedisCallback;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.script.RedisScript;
import org.springframework.data.redis.core.types.Expiration;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.awt.print.Book;
import java.util.Arrays;
import java.util.List;
import java.util.UUID;
/**
* @author zhuzhaoman
* @date 2020/5/2 0002 17:05
* @description 基于redis分布式锁
*/
@RestController
@Slf4j
public class RedisLockController { 

@Autowired
private RedisTemplate redisTemplate;
@RequestMapping("/redisLock")
public String redisLock() throws InterruptedException { 

log.info("我进入了方法");
String key = "redisKey";
String value = UUID.randomUUID().toString();
RedisCallback<Boolean> redisCallback = redisConnection -> { 

// 设置NX
RedisStringCommands.SetOption setOption = RedisStringCommands.SetOption.ifAbsent();
// 设置过期时间
Expiration expiration = Expiration.seconds(30);
// 序列化key和value
byte[] redisKey = redisTemplate.getKeySerializer().serialize(key);
byte[] redisValue = redisTemplate.getValueSerializer().serialize(value);
// 执行set nx 操作
Boolean result = redisConnection.set(redisKey, redisValue, expiration, setOption);
return result;
};
// 获取分布式锁
Boolean lock = (Boolean) redisTemplate.execute(redisCallback);
if (lock) { 

log.info("我进入了锁！");
Thread.sleep(15000);
}
String script = "if redis.call(\"get\",KEYS[1]) == ARGV[1] then\n" +
" return redis.call(\"del\",KEYS[1])\n" +
"else\n" +
" return 0\n" +
"end";
RedisScript<Boolean> redisScript = RedisScript.of(script, Boolean.class);
List<String> keys = Arrays.asList(key);
Boolean result = (Boolean) redisTemplate.execute(redisScript, keys, value);
log.info("释放锁的结果：" + result);
log.info("方法执行完成");
return "方法执行完成";
}
}

3.2、yml配置

spring.datasource.username=root
spring.datasource.password=1999114zzm
spring.datasource.url=jdbc:mysql://localhost:3306/fen_bu_shi_suo?serverTimezone=Asia/Shanghai&useSSL=false
mybatis.mapper-locations=/mapper/*.xml
logging.pattern.dateformat=HH:mm:ss
spring.redis.host=你ip
spring.redis.port=6379

四、基于分布式锁解决定时任务重复问题

4.1、封装redis分布式锁

package com.example.distributedemo.lock;
import lombok.extern.slf4j.Slf4j;
import org.springframework.data.redis.connection.RedisStringCommands;
import org.springframework.data.redis.core.RedisCallback;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.script.RedisScript;
import org.springframework.data.redis.core.types.Expiration;
import java.util.Arrays;
import java.util.List;
import java.util.UUID;
/**
* @author zhuzhaoman
* @date 2020/5/2 0002 17:46
* @description 描述
*/
@Slf4j
public class RedisLockUtils implements AutoCloseable{ 

private RedisTemplate redisTemplate;
private String key;
private String value;
// 单位：秒
private int expireTime;
public RedisLockUtils(RedisTemplate redisTemplate, String key, int expireTime) { 

this.redisTemplate = redisTemplate;
this.key = key;
this.value = UUID.randomUUID().toString();
this.expireTime = expireTime;
}
/**
* 获取分布式锁
* @return
*/
public boolean getLock() { 

RedisCallback<Boolean> redisCallback = redisConnection -> { 

// 设置NX
RedisStringCommands.SetOption setOption = RedisStringCommands.SetOption.ifAbsent();
// 设置过期时间
Expiration expiration = Expiration.seconds(expireTime);
// 序列化key和value
byte[] redisKey = redisTemplate.getKeySerializer().serialize(key);
byte[] redisValue = redisTemplate.getValueSerializer().serialize(value);
// 执行set nx 操作
Boolean result = redisConnection.set(redisKey, redisValue, expiration, setOption);
return result;
};
// 获取分布式锁
Boolean lock = (Boolean) redisTemplate.execute(redisCallback);
return lock;
}
/**
* 释放锁
* @return
*/
public boolean unLock() { 

String script = "if redis.call(\"get\",KEYS[1]) == ARGV[1] then\n" +
" return redis.call(\"del\",KEYS[1])\n" +
"else\n" +
" return 0\n" +
"end";
RedisScript<Boolean> redisScript = RedisScript.of(script, Boolean.class);
List<String> keys = Arrays.asList(key);
Boolean result = (Boolean) redisTemplate.execute(redisScript, keys, value);
log.info("释放锁的结果：" + result);
return result;
}
@Override
public void close() throws Exception { 

// 释放锁
unLock();
}
}

4.2、重要代码

package com.example.distributedemo.controller;
import com.example.distributedemo.lock.RedisLockUtils;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
/**
* @author zhuzhaoman
* @date 2020/5/2 0002 17:05
* @description 描述
*/
@RestController
@Slf4j
public class RedisLockController { 

@Autowired
private RedisTemplate redisTemplate;
@RequestMapping("/redisLock")
public String redisLock() throws InterruptedException { 

log.info("我进入了方法");
// 获取锁
try(RedisLockUtils redisLock = new RedisLockUtils(redisTemplate, "redisKey", 30)) { 

boolean lock = redisLock.getLock();
if (lock) { 

log.info("我进入了锁！");
Thread.sleep(15000);
}
}catch (Exception e){ 

e.printStackTrace();
}
log.info("方法执行完成");
return "方法执行完成";
}
}

4.3、解决任务重复

• 启动类

package com.example.distributedemo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableScheduling;
import tk.mybatis.spring.annotation.MapperScan;
@SpringBootApplication
@EnableScheduling // 开启定时任务
public class DistributeDemoApplication { 

public static void main(String[] args) { 

SpringApplication.run(DistributeDemoApplication.class, args);
}
}

• 定时任务

package com.example.distributedemo.service;
import com.example.distributedemo.lock.RedisLockUtils;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Service;
/**
* @author zhuzhaoman
* @date 2020/5/2 0002 18:17
* @description 描述
*/
@Service
@Slf4j
public class SchedulerService { 

@Autowired
private RedisTemplate redisTemplate;
@Scheduled(cron = "0/5 * * * * ?")
public void sendSms() { 

try(RedisLockUtils redisLock = new RedisLockUtils(redisTemplate, "autoSms", 30)) { 

boolean lock = redisLock.getLock();
if (lock) { 

log.info("向138xxxxx用户发短信！");
}
}catch (Exception e) { 

e.printStackTrace();
}
}
}

五、zookeeper分布式锁代码实现

5.1、重要代码

package com.example.distributedemo.lock;
import lombok.extern.slf4j.Slf4j;
import org.apache.zookeeper.*;
import org.apache.zookeeper.data.Stat;
import java.io.IOException;
import java.util.Collections;
import java.util.List;
/**
* @author zhuzhaoman
* @date 2020/5/2 0002 18:52
* @description 描述
*/
@Slf4j
public class ZkLock implements AutoCloseable, Watcher { 

private ZooKeeper zooKeeper;
private String znode;
public ZkLock() throws IOException { 

this.zooKeeper = new ZooKeeper("49.232.26.207:2181", 60000, this);
}
public boolean getLock(String businessCode) { 

try { 

// 创建业务根节点
Stat stat = zooKeeper.exists("/" + businessCode, false);
if (stat==null){ 

zooKeeper.create("/" + businessCode,
businessCode.getBytes(),
ZooDefs.Ids.OPEN_ACL_UNSAFE,
CreateMode.PERSISTENT);
}
// 创建瞬时有序节点 /order/order_序号
znode = zooKeeper.create("/" + businessCode + "/" + businessCode + "_",
businessCode.getBytes(),
ZooDefs.Ids.OPEN_ACL_UNSAFE,
CreateMode.EPHEMERAL_SEQUENTIAL);
// 获取业务节点下所有的子节点
List<String> childrenNodes = zooKeeper.getChildren("/" + businessCode, false);
// 子节点排序
Collections.sort(childrenNodes);
// 获取序列号最小的（第一个）子节点
String firstNode = childrenNodes.get(0);
// 如果创建的节点时第一个子节点，则获得锁
if (znode.endsWith(firstNode)) { 

return true;
}
// 不是第一个子节点，则监听前一个节点
String lastNode = firstNode;
for (String node: childrenNodes){ 

if (znode.endsWith(node)) { 

zooKeeper.exists("/" + businessCode + "/" + lastNode, true);
break;
} else { 

lastNode = node;
}
}
synchronized (this) { 

wait();
}
return true;
}catch (Exception e) { 

e.printStackTrace();
}
return false;
}
@Override
public void process(WatchedEvent watchedEvent) { 

if (watchedEvent.getType() == Event.EventType.NodeDeleted) { 

synchronized (this) { 

notify();
}
}
}
@Override
public void close() throws Exception { 

zooKeeper.delete(znode, -1);
zooKeeper.close();
log.info("锁被释放");
}
}

5.2、测试代码

package com.example.distributedemo.controller;
import com.example.distributedemo.lock.ZkLock;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
/**
* @author zhuzhaoman
* @date 2020/5/2 0002 19:45
* @description 描述
*/
@RestController
@Slf4j
public class ZookeeperController { 

@RequestMapping("/zkLock")
public String zookeeperLock() { 

log.info("我进入了方法");
try(ZkLock zkLock = new ZkLock()) { 

boolean order = zkLock.getLock("order");
if (order) { 

log.info("获得了锁！");
Thread.sleep(10000);
}
}catch (Exception e){ 

e.printStackTrace();
}
log.info("方法执行完成！");
return "方法执行完成！";
}
}

六、基于curator分布式锁（推荐）

6.1、Application启动类

package com.example.distributedemo;
import org.apache.curator.RetryPolicy;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.retry.ExponentialBackoffRetry;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.scheduling.annotation.EnableScheduling;
import tk.mybatis.spring.annotation.MapperScan;
@SpringBootApplication
public class DistributeDemoApplication { 

public static void main(String[] args) { 

SpringApplication.run(DistributeDemoApplication.class, args);
}
@Bean(initMethod = "start", destroyMethod = "close")
public CuratorFramework getCuratorFramework() { 

RetryPolicy retryPolicy = new ExponentialBackoffRetry(30000, 3);
CuratorFramework curatorFramework = CuratorFrameworkFactory.newClient("49.232.26.207:2181", retryPolicy);
return curatorFramework;
}
}

6.2、测试代码

package com.example.distributedemo.controller;
import com.example.distributedemo.lock.ZkLock;
import lombok.extern.slf4j.Slf4j;
import org.apache.curator.RetryPolicy;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.recipes.locks.InterProcessMutex;
import org.apache.curator.retry.ExponentialBackoffRetry;
import org.checkerframework.checker.units.qual.A;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.concurrent.TimeUnit;
/**
* @author zhuzhaoman
* @date 2020/5/2 0002 19:45
* @description 描述
*/
@RestController
@Slf4j
public class ZookeeperController { 

@Autowired
private CuratorFramework curatorFramework;
@RequestMapping("/curatorLock")
public String curatorLock() throws Exception { 

log.info("我进入了方法");
InterProcessMutex lock = new InterProcessMutex(curatorFramework, "/order");
try { 

if (lock.acquire(30, TimeUnit.SECONDS)) { 

log.info("我获得了锁！");
Thread.sleep(10000);
}
} catch (Exception e) { 

e.printStackTrace();
} finally { 

log.info("释放了锁");
lock.release();
}
log.info("方法执行完成！");
return "方法执行完成！";
}
}

七、基于redisson分布式锁（推荐）

7.1、测试代码

package com.example.distributedemo.controller;
import lombok.extern.slf4j.Slf4j;
import org.redisson.Redisson;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.redisson.config.Config;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.concurrent.TimeUnit;
/**
* @author zhuzhaoman
* @date 2020/5/2 0002 16:53
* @description 描述
*/
@RestController
@Slf4j
public class RedissonLockController { 

@RequestMapping("/redissonLock")
public String redissonLock() throws InterruptedException { 

Config config = new Config();
config.useSingleServer().setAddress("redis://49.232.26.207:6379");
RedissonClient redissonClient = Redisson.create(config);
RLock rLock = redissonClient.getLock("order");
log.info("我进入了方法");
rLock.lock(30, TimeUnit.SECONDS);
log.info("获得了锁");
Thread.sleep(15000);
log.info("释放了锁");
rLock.unlock();
log.info("方法执行完成");
return "方法执行完成";
}
}

八、springboot引入redisson（推荐）

8.1、配置文件

spring.datasource.username=root
spring.datasource.password=1999114zzm
spring.datasource.url=jdbc:mysql://localhost:3306/fen_bu_shi_suo?serverTimezone=Asia/Shanghai&useSSL=false
mybatis.mapper-locations=/mapper/*.xml
logging.pattern.dateformat=HH:mm:ss
spring.redis.host=49.232.26.207
spring.redis.port=6379

8.2、测试文件

package com.example.distributedemo.controller;
import lombok.extern.slf4j.Slf4j;
import org.checkerframework.checker.units.qual.A;
import org.redisson.Redisson;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.redisson.config.Config;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.concurrent.TimeUnit;
/**
* @author zhuzhaoman
* @date 2020/5/2 0002 16:53
* @description 描述
*/
@RestController
@Slf4j
public class RedissonLockController { 

@Autowired
private RedissonClient redissonClient;
@RequestMapping("/redissonLock")
public String redissonLock() throws InterruptedException { 

RLock rLock = redissonClient.getLock("order");
log.info("我进入了方法");
rLock.lock(30, TimeUnit.SECONDS);
log.info("获得了锁");
Thread.sleep(15000);
log.info("释放了锁");
rLock.unlock();
log.info("方法执行完成");
return "方法执行完成";
}
}

九、完整的pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.7.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>distribute-demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>distribute-demo</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.redisson</groupId>
<artifactId>redisson</artifactId>
<version>3.11.2</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>3.6.0</version>
</dependency>
<dependency>
<groupId>org.apache.curator</groupId>
<artifactId>curator-recipes</artifactId>
<version>4.2.0</version>
</dependency>
<dependency>
<groupId>org.redisson</groupId>
<artifactId>redisson-spring-boot-starter</artifactId>
<version>3.11.2</version>
</dependency>
<!-- mybatis -->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.1.0</version>
</dependency>
<dependency>
<groupId>org.mybatis.generator</groupId>
<artifactId>mybatis-generator-core</artifactId>
<version>1.3.3</version>
</dependency>
<dependency>
<groupId>tk.mybatis</groupId>
<artifactId>mapper</artifactId>
<version>4.1.5</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.11</version>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.1.0</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.mybatis.generator</groupId>
<artifactId>mybatis-generator-maven-plugin</artifactId>
<version>1.3.7</version>
<dependencies>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.17</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
</project>