java秒杀系统方案优化1-3 集成Mybatis+Druid

前言

 　　mybatis参考文档: https://mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/index.html

集成Mybatis+Druid

• 添加依赖

    <dependency>
      <groupId>org.mybatis.spring.boot</groupId>
      <artifactId>mybatis-spring-boot-starter</artifactId>
      <version>1.3.1</version>
    </dependency>

    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
    </dependency>

    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.0.5</version>
    </dependency>

• 添加配置

# mybatis
mybatis.type-aliases-package=com.luckey.flashsale.domain
mybatis.configuration.map-underscore-to-camel-case=true
mybatis.configuration.default-fetch-size=100
mybatis.configuration.default-statement-timeout=3000
mybatis.mapperLocations = classpath:com/luckey/flashsale/dao/*.xml
# druid
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/miaosha?useUnicode=true&characterEncoding=utf-8&allowMultiQueries=true&useSSL=false
spring.datasource.username=root
spring.datasource.password=1234
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.filters=stat
spring.datasource.maxActive=2
spring.datasource.initialSize=1
spring.datasource.maxWait=60000
spring.datasource.minIdle=1
spring.datasource.timeBetweenEvictionRunsMillis=60000
spring.datasource.minEvictableIdleTimeMillis=300000
spring.datasource.validationQuery=select 'x'
spring.datasource.testWhileIdle=true
spring.datasource.testOnBorrow=false
spring.datasource.testOnReturn=false
spring.datasource.poolPreparedStatements=true
spring.datasource.maxOpenPreparedStatements=20

•  编写一个demo展示查询效果

 控制器里新增一个查询db方法

    @RequestMapping("/db/get")
    @ResponseBody
    public Result<User> dbGet() {
        User user = userService.getById(1);
        return Result.success(user);
    }

依次新建User,UserDao,UserService对象

@Mapper
public interface UserDao {

    @Select("select * from user where id = #{id}")
    public User getById(@Param("id") int id);
}

@Service
public class UserService {
    @Resource
    private UserDao userDao;

    public User getById(int id){
        return userDao.getById(id);
    }
}

重启服务查看页面:

事务Transaction

 　　验证一下mybatis的事务,简单思路:db中已有id为1的数据,先插入一条id为3的记录,然后再插入一条id为1的会报错(主键冲突),验证一下id为3的记录是否会回滚.

cotroller

    @RequestMapping("/db/tx")
    @ResponseBody
    public Result<Boolean> dbTx() {
        Boolean result = userService.tx();
        return Result.success(result);
    }

dao

    @Insert("insert into user(id,name) values (#{id}, #{name})")
    public int insert(User user);

service

    @Transactional
    public Boolean tx() {
        User u1 = new User();
        u1.setId(2);
        u1.setName("2222");
        userDao.insert(u1);

        User u2 = new User();
        u2.setId(1);
        u2.setName("11111");
        userDao.insert(u2);

        return true;
    }

重启服务访问 /db/tx 报错,发现数据库中没有新增记录

 

 

 备注:如果去掉@Transactional 注解或者捕捉异常,则会新增一条id为2的记录

 

后记