SpringMvc整合Mybatis并使用声明式事务

（1）、引入相关依赖

    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.1.12</version>
    </dependency>

    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.13</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-orm</artifactId>
      <version>4.3.22.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>2.0.0</version>
    </dependency>
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.5.0</version>
    </dependency>

（2）、编写Mybatis配置类

package cn.coreqi.config;

import com.alibaba.druid.pool.DruidDataSource;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import javax.sql.DataSource;

@EnableTransactionManagement    //启动事务管理器
@Configuration
@MapperScan(value = "cn.coreqi.mapper") //扫描Mapper文件
public class MybatisConfig {
    @Bean
    public DataSource dataSource(){
        DruidDataSource ds = new DruidDataSource();
        ds.setDriverClassName("com.mysql.jdbc.Driver");
        ds.setUrl("jdbc:mysql://localhost:3306/mybatisdemo?serverTimezone=UTC");
        ds.setUsername("root");
        ds.setPassword("123456");
        return ds;
    }

    //注册Mybatis SqlSessionFactory
    @Bean
    public SqlSessionFactoryBean sqlSessionFactory(DataSource dataSource){
        SqlSessionFactoryBean sqlSessionFactory = new SqlSessionFactoryBean();
        sqlSessionFactory.setDataSource(dataSource);
        return sqlSessionFactory;
    }
    
    //注册事务管理器
    @Bean
    public DataSourceTransactionManager transactionManager(DataSource dataSource){
        DataSourceTransactionManager transactionManager = new DataSourceTransactionManager();
        transactionManager.setDataSource(dataSource);
        return transactionManager;
    }
}

（3）、编写Mapper文件

package cn.coreqi.mapper;

import cn.coreqi.entities.User;
import org.apache.ibatis.annotations.*;

@Mapper
public interface UserMapper{
    @Select("select * from users where Id = #{id}")
    public User getUserById(Integer id);
    @Insert("insert into users(UserName,PassWord,Enabled) values(#{UserName},#{PassWord},#{Enabled})")
    @Options(useGeneratedKeys = true,keyProperty = "Id")
    public int addUser(User user);
    @Update("update users set UserName = #{UserName},PassWord = #{PassWord},Enabled = #{Enabled} where Id = #{Id}")
    public int modifyUser(User user);
    @Delete("delete from users where Id = #{id}")
    public void delById(Integer id);
}

（4）、编写Service文件

package cn.coreqi.service;

import cn.coreqi.entities.User;
import cn.coreqi.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Isolation;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

import java.io.IOException;
import java.sql.SQLException;

@Service
public class UserService {
    @Autowired
    private UserMapper userMapper;

    @Transactional(readOnly = true)
    public User getUserById(Integer id){
        return userMapper.getUserById(id);
    }

    @Transactional
    public User insertUser(User user){
        userMapper.addUser(user);
        return user;
    }

    //@Transactional属性
    //  1.propagation   指定当前事务的传播行为，共7种，常用的有REQUIRES_NEW和REQUIRED
    //  2.isolation     指定当前事务的隔离级别，共5种，常用的有READ_COMMITTED，*事务的隔离级别要得到底层数据库的支持，而不是应用程序和框架的支持
    //  3.rollbackFor&noRollbackFor   指定当前事务的回滚属性，rollbackFor指定遇到那些异常进行回滚，noRollbackFor指定遇到那些异常不进行回滚。*如果不指定这两个属性的默认情况下
    //                                Spring的声明式事务对所有的运行时异常（RuntimeException）和Error类型的异常进行回滚。
    //  4.readOnly      指定当前事务是否只读，true表示这个事务只读取数据而不对数据做修改，这样可以帮助数据库引擎优化事务
    //  5.timeout       指定当前事务可以保持多久，防止长期运行事务占用资源，单位秒。
    @Transactional(propagation = Propagation.REQUIRES_NEW,isolation = Isolation.READ_COMMITTED,
            rollbackFor = {IOException.class, SQLException.class},noRollbackFor = {ArithmeticException.class},
    readOnly = false,timeout = 30)
    public User modifyUser(User user){
        userMapper.modifyUser(user);
        return user;
    }
    
    @Transactional
    public void delById(Integer id){
        userMapper.delById(id);

    }
}