【Spring5】Spring5基础教程(9)

前言：

本文内容：事务回顾、Spring声明式事务

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Spring5笔记代码下载地址：

蓝奏云：下载地址 密码：joker

百度云：下载地址 提取码：aidp

事务回顾

回顾

• 把一组业务当成一个业务来做，要么都成功，要么都失败
• 事务在项目开发中，十分重要，涉及到数据一致性问题
• 确保完整性和一致性

事务ACID原则

• 原子性

• 一致性

• 隔离性

  多个业务可能操作同一个资源，防止数据损坏

• 持久性

  事务一旦提交，无论系统发生什么问题，结果都不会在被影响

搭建事务测试环境

UserMapper.java

package com.jokerdig.mapper;

import com.jokerdig.pojo.User;
import org.apache.ibatis.annotations.Param;

import java.util.List;

/**
 * @author Joker大雄
 * @data 2022/5/23 - 13:25
 **/
public interface UserMapper {
    public List<User> selectUser();
    // 添加一个用户
    public int add(User user);
    // 删除一个用户
    public int delete(int id);
}

UserMapper.xml

<?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.jokerdig.mapper.UserMapper">

    <!--    查询用户 来测试缓存-->
    <select id="selectUser" resultType="user">
        select * from user
    </select>
<!--    添加-->
    <insert id="add" parameterType="user">
        insert into user (id,name,pwd) value (#{id},#{name},#{pwd})
    </insert>
<!--    删除 这里delete写错为了测试事务是否生效 不配置事务，即使删除报错，也没影响数据插入-->
    <delete id="delete" parameterType="int">
        deletes from user where id=#{id}
    </delete>
</mapper>

UserMapperImpl.java

package com.jokerdig.mapper;

import com.jokerdig.pojo.User;
import org.mybatis.spring.support.SqlSessionDaoSupport;

import java.util.List;

/**
 * @author Joker大雄
 * @data 2022/5/23 - 14:06
 **/
public class UserMapperImpl extends SqlSessionDaoSupport implements UserMapper{

    // 查询所有
    public List<User> selectUser() {
        User user = new User(4, "小王", "123123");
        UserMapper mapper = getSqlSession().getMapper(UserMapper.class);
        mapper.add(user);
        mapper.delete(4);
        return mapper.selectUser();
    }

    //添加
    public int add(User user) {
        UserMapper mapper = getSqlSession().getMapper(UserMapper.class);
        return mapper.add(user);
    }

//    删除
    public int delete(int id) {
        UserMapper mapper = getSqlSession().getMapper(UserMapper.class);
        return mapper.delete(id);
    }
}

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">


<!--    datasource 使用spring数据源代替mybatis数据源-
            DriverManagerDataSource
-->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=false&amp;serverTimezone=UTC"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
    </bean>

<!--    sqlSessionFactory-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
<!--        绑定mybatis-->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <property name="mapperLocations" value="classpath:com/jokerdig/mapper/*.xml"/>
    </bean>
    <!--   引入UserMapperImpl2 使用SqlSessionDaoSupport  -->
    <bean id="userMapper" class="com.jokerdig.mapper.UserMapperImpl">
        <property name="sqlSessionFactory" ref="sqlSessionFactory" />
    </bean>
</beans>

mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!--    别名-->
    <typeAliases>
        <package name="com.jokerdig.pojo"/>
    </typeAliases>
<!--    设置-->
</configuration>

User.java

package com.jokerdig.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

/**
 * @author Joker大雄
 * @data 2022/5/23 - 13:03
 **/
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
    private int id;
    private String name;
    private String pwd;
}

SpringTest.java

package com.jokerdig.test;

import com.jokerdig.mapper.UserMapper;
import com.jokerdig.pojo.User;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import java.util.List;

/**
 * @author Joker大雄
 * @data 2022/5/25 - 11:25
 **/
public class SpringTest {
    @Test
    public void test12(){
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");

        UserMapper userMapper = context.getBean("userMapper", UserMapper.class);

        List<User> users = userMapper.selectUser();

        for (User user : users) {
            System.out.println(user);
        }
    }
}

Spring声明式事务

• 声明式事务 AOP
• 编程式事务 需要在代码中，进行事务的管理

添加事务

在上方代码的基础上添加事务

在pom.xml添加事务需要的依赖

<dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.22</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.6</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.19</version>
        </dependency>
        <!--        连接spring-jdbc-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.3.8</version>
        </dependency>
        <!--        mybatis-spring-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.2</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.10</version>
        </dependency>
<!--        使用事务需要的依赖-->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.7</version>
        </dependency>

    </dependencies>
    <!--    解决资源导出问题-->

    <build>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
        <!--        junit测试必须的插件 否则会报错-->
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>2.22.1</version>
                <configuration>
                    <skipTests>true</skipTests>
                </configuration>
            </plugin>
        </plugins>
    </build>

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
       http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">


<!--    datasource 使用spring数据源代替mybatis数据源-
            DriverManagerDataSource
-->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=false&amp;serverTimezone=UTC"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
    </bean>

<!--    sqlSessionFactory-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
<!--        绑定mybatis-->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <property name="mapperLocations" value="classpath:com/jokerdig/mapper/*.xml"/>
    </bean>
    <!--   引入UserMapperImpl2 使用SqlSessionDaoSupport  -->
    <bean id="userMapper" class="com.jokerdig.mapper.UserMapperImpl">
        <property name="sqlSessionFactory" ref="sqlSessionFactory" />
    </bean>
<!--    配置声明式事务-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    </bean>
<!--    结合AOP植入事务-->
<!--    配置事务通知-->
    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
<!--             propagation="REQUIRED" 为默认选择 也可以不写-->
            <tx:method name="add" propagation="REQUIRED"/>
            <tx:method name="delete"/>
            <tx:method name="update"/>
            <tx:method name="query" read-only="true"/>
            <tx:method name="*"/>
        </tx:attributes>
    </tx:advice>
<!--    配置事务切入-->
    <aop:config>
        <aop:pointcut id="txPointCut" expression="execution(* com.jokerdig.mapper.*.*(..))"/>
        <aop:advisor advice-ref="txAdvice" pointcut-ref="txPointCut"/>
    </aop:config>
</beans>

运行结果

User(id=1, name=admin, pwd=123)
User(id=2, name=abc, pwd=123)
User(id=3, name=def, pwd=123)
User(id=4, name=小王, pwd=123123)

Process finished with exit code 0

为什么需要事务

• 如果不配置事务，可能存在数据不一致的情况
• 如果我们不在Spring中去配置声明事务，就需要在代码中手动配置事务
• 事务在项目开发中十分重要，涉及到数据的一致性和完整性

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