整合Mybatis-Spring

文章目录

1.回顾Mybatis

1.0创建数据库

CREATE DATABASE `mybatis`;

USE `mybatis`;

CREATE TABLE `user`(
  `id` INT(20) NOT NULL PRIMARY KEY,
  `name` VARCHAR(30) DEFAULT NULL,
  `pwd` VARCHAR(30) DEFAULT NULL
)ENGINE=INNODB DEFAULT CHARSET=utf8;

INSERT INTO `user`(`id`,`name`,`pwd`) VALUES 
(1,'王麻子','123456'),
(2,'张三','123456'),
(3,'李四','123890');

完成CRUD需要下面的操作。

导入依赖
新建实体类
编写操作用户接口
编写绑定UserMapper.xml文件
编写mybatis-config.xml文件
测试

1.1 导入依赖(pom.xml)

 <dependencies>
        <!-- lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.12</version>
            <scope>provided</scope>
        </dependency>

        <!-- 单元测试的jar包-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13</version>
            <scope>test</scope>
        </dependency>

        <!-- 数据库的jar包-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
        <!-- 整合mybatis-spring的jar包-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.4</version>
        </dependency>

        <!-- 使用mybatis的jar包-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.4</version>
        </dependency>


        <!--使用spring的jar包-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.6.RELEASE</version>
        </dependency>

        <!-- spring连接数据库需要spring-jdbc-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.2.6.RELEASE</version>
        </dependency>

        <!-- 使用AOP需要导入的jar包-->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.5</version>
        </dependency>

    </dependencies>

1.2新建实体类

新建实体类之前需要连接数据库！
注意：新建实体类的时候字段名应该和数据库的列名尽量保持一致！

public class User {
    
    
    private int id;
    private String name;
    private String pwd;

    public int getId(){
    
    
        return id;
    }
    public void setId(int id){
    
    
        this.id = id;
    }

    public String getName() {
    
    
        return name;
    }

    public void setName(String name) {
    
    
        this.name = name;
    }

    public String getPwd() {
    
    
        return pwd;
    }

    public void setPwd(String pwd) {
    
    
        this.pwd = pwd;
    }

    @Override
    public String toString() {
    
    
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", pwd='" + pwd + '\'' +
                '}';
    }
}

1.3编写操作用户的接口

操作用户的接口可以完成CRUD

public interface UserMapper {
    
    
    //查询所有的用户信息
    List<User> selectUser();
}

1.4 编写绑定UserMapper.xml文件

<?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.li.mapper.UserMapper">
   <select id="selectUser" resultType="user">
       select * from user;
   </select>
</mapper>

1.5编写mybatis-config.xml文件

要和 Spring 一起使用 MyBatis，需要在 Spring 应用上下文中定义至少两样东西：一个 SqlSessionFactory 和至少一个数据映射器类。

在 MyBatis-Spring 中，可使用 SqlSessionFactoryBean来创建 SqlSessionFactory。要配置这个工厂 bean，只需要把下面代码放在 Spring 的 XML 配置文件中：

<?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>
    <typeAliases>
        <package name="com.li.pojo"/>
    </typeAliases>
    <environments default="development">
        <!-- 里面的每一个environment 代表一个具体环境-->
        <environment id="development">
            <!-- transactionManager 事物管理器-->
            <transactionManager type="JDBC"/>
            <!-- dataSource 数据源的配置-->
            <dataSource type="POOLED">
                <!-- 连接数据库的配置-->
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url"
                          value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&amp;useUnicode=true&amp;characterEncoding=utf-8"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
      <mapper class="com.li.mapper.UserMapper"/>
    </mappers>
</configuration>

1.6 测试

@Test
    public void test() throws IOException {
    
    
        //指定全局配置文件
        String resource = "mybatis-config.xml";
        //读取配置文件
        InputStream inputStream = Resources.getResourceAsStream(resource);
        //构建sqlSessionFactory
        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        //获取sqlSession对象
        SqlSession sqlSession = sessionFactory.openSession(true);
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<User> users = mapper.selectUser();
        for (User user : users) {
    
    
            System.out.println(user);
        }
    }

测试过程中出现错误下面错误：
在这里插入图片描述
只需要在pom.xml中导入处理maven静态资源过滤问题

 <!-- maven静态资源过滤问题-->
    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>

再次测试：打印输出

User{id=1, name=‘王麻子’, pwd=‘123456’}
User{id=2, name=‘张三’, pwd=‘123456’}
User{id=3, name=‘李四’, pwd=‘123890’}

2.整合Mybatis-Spring 方式一

mybatis-spring官网

编写spring-dao.xml文件
实现UserMapper接口的实现类
测试

2.1编写spring-dao.xml文件

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

    <!-- dataSource 使用spring配置代替mybatis-config.xml中的数据源-->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&amp;useUnicode=true&amp;characterEncoding=utf-8"/>
        <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"/>
        <!-- 关联mybatis-config.xml -->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <!-- value="com/li/mapper/*.xml" 关联所有的xml文件-->
        <property name="mapperLocations" value="classpath:com/li/mapper/UserMapper.xml"/>
    </bean>
   <!-- SqlSessionTemplate就是我们使用的sqlSession -->
    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
       <!-- 使用构造方法的参数创建SqlSessionTemplate对象 因为SqlSessionTemplate没有set方法 -->
        <constructor-arg index="0" ref="sqlSessionFactory"/>
    </bean>
</beans>

为了方便开发新建一个总的xml文件application.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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       https://www.springframework.org/schema/beans/spring-beans.xsd">
    <import resource="spring-dao.xml"/>
    <bean id="userMapper" class="com.li.mapper.UserMapperImpl">
        <property name="sqlSession" ref="sqlSession"/>
    </bean>
</beans>

2.2 实现UserMapper接口的实现类

mybatis-spring为我们提供了映射器，这样就可以直接注入到bean中

public class UserMapperImpl  implements UserMapper {
    
    
    private SqlSessionTemplate sqlSession;

    public void setSqlSession(SqlSessionTemplate sqlSession) {
    
    
        this.sqlSession = sqlSession;
    }
    public List<User> selectUser() {
    
    
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        return mapper.selectUser();
    }
}

2.4整合后的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>
<!-- 一般将typeAliases、settings放在mybatis-config.xml中-->
    <typeAliases>
        <package name="com.li.pojo"/>
    </typeAliases>
</configuration>

2.3测试

public class MyTest {
    
    
    @Test
    public void test() throws IOException {
    
    
        ApplicationContext context = new ClassPathXmlApplicationContext("spring-dao.xml");
        UserMapper userMapper = context.getBean("userMapper", UserMapper.class);
        List<User> users = userMapper.selectUser();
        for (User user : users) {
    
    
            System.out.println(user);
        }
    }
}

3.整合Mybatis-Spring 方式二

SqlSessionDaoSupport 是一个抽象的支持类，用来为你提供 SqlSession。调用 getSqlSession() 方法你会得到一个 SqlSessionTemplate，之后可以用于执行 SQL 方法，就像下面这样:

3.1接口的实现类并且继SqlSessionDaoSupport类

public class UserMapperImpl2 extends SqlSessionDaoSupport implements UserMapper {
    
    
    public List<User> selectUser() {
    
    
        return getSqlSession().getMapper(UserMapper.class).selectUser();
    }
}

3.2spring-dao.xml文件

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

    <!-- dataSource -->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&amp;useUnicode=true&amp;characterEncoding=utf-8"/>
        <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"/>
        <!-- 关联mybatis-config.xml -->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <!-- value="com/li/mapper/*.xml" 关联所有的xml文件-->
        <property name="mapperLocations" value="classpath:com/li/mapper/UserMapper.xml"/>
    </bean>

applicationContext.xml文件

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

    <bean id="userMapper2" class="com.li.mapper.UserMapperImpl2">
        <property name="sqlSessionFactory" ref="sqlSessionFactory"/>
    </bean>

    <bean id="userMapper" class="com.li.mapper.UserMapperImpl">
        <property name="sqlSession" ref="sqlSession"/>
    </bean>
</beans>

3.3测试：

public class MyTest {
    
    
    @Test
    public void test() throws IOException {
    
    

        ApplicationContext context = new ClassPathXmlApplicationContext("spring-dao.xml");
        UserMapper userMapper = context.getBean("userMapper2", UserMapper.class);
        List<User> users = userMapper.selectUser();
        for (User user : users) {
    
    
            System.out.println(user);
        }
    }
}

结果：

User{id=1, name=‘王麻子’, pwd=‘123456’}
User{id=2, name=‘张三’, pwd=‘123456’}
User{id=3, name=‘李四’, pwd=‘123890’}

4.事务

一般来说，事务是必须满足4个条件（ACID）：：原子性（Atomicity，或称不可分割性）、一致性（Consistency）、隔离性（Isolation，又称独立性）、持久性（Durability）。
事务用来管理 insert,update,delete 语句

原子性：一个事务（transaction）中的所有操作，要么全部完成，要么全部不完成，不会结束在中间某个环节。事务在执行过程中发生错误，会被回滚（Rollback）到事务开始前的状态，就像这个事务从来没有执行过一样。
一致性：在事务开始之前和事务结束以后，数据库的完整性没有被破坏。这表示写入的资料必须完全符合所有的预设规则，这包含资料的精确度、串联性以及后续数据库可以自发性地完成预定的工作。
隔离性：数据库允许多个并发事务同时对其数据进行读写和修改的能力，隔离性可以防止多个事务并发执行时由于交叉执行而导致数据的不一致。事务隔离分为不同级别，包括读未提交（Read uncommitted）、读提交（read committed）、可重复读（repeatable read）和串行化（Serializable）。
持久性：事务处理结束后，对数据的修改就是永久的，即便系统故障也不会丢失。

4.1操作用户的接口

public interface UserMapper {
    
    
    //查询所有的用户信息
    List<User> selectUser();
    //添加用户
    int insertUser(User user);
    //删除用户
    int deleteUser(int id);
}

4.2编写UserMapper.xml文件

<?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.li.mapper.UserMapper">
    <select id="selectUser" resultType="user">
        select * from mybatis.user;
    </select>

    <insert id="insertUser" parameterType="user">
        insert into mybatis.user(id, name, pwd) values (#{
    
    id},#{
    
    name},#{
    
    pwd});
    </insert>
 <!-- 模拟要么完成要么不完成 故意写错delete-->
    <delete id="deletesUser" parameterType="int">
        deletes from mybatis.user where id = #{
    
    id};
    </delete>

</mapper>

4.3spring-dao.xml

MyBatis-Spring 借助了 Spring 中的 DataSourceTransactionManager 来实现事务管理。

<?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
       https://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/aop
       https://www.springframework.org/schema/aop/spring-aop.xsd
       http://www.springframework.org/schema/tx
       https://www.springframework.org/schema/tx/spring-tx.xsd">


    <!-- 使用spring接管mybatis-config.xml 中dataSource的内容-->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&amp;useUnicode=true&amp;characterEncoding=utf-8"/>
        <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配置文件-->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <property name="mapperLocations" value="classpath:com/li/mapper/*.xml"/>
    </bean>
</beans>

4.3.1applicationContext.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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       https://www.springframework.org/schema/beans/spring-beans.xsd">

<import resource="spring-dao.xml"/>
<bean id="userMapper" class="com.li.mapper.UserMapperImpl">
    <property name="sqlSessionFactory" ref="sqlSessionFactory"/>
</bean>
</beans>

4.4编写操作用户接口的实现类

public class UserMapperImpl extends SqlSessionDaoSupport implements UserMapper {
    
    

    public List<User> selectUser() {
    
    
        User user = new User(4, "陈赫", "123456");
        UserMapper mapper = getSqlSession().getMapper(UserMapper.class);
        mapper.insertUser(user);
        mapper.deleteUser(3);
        return mapper.selectUser();
    }

    public int insertUser(User user) {
    
    
        return getSqlSession().getMapper(UserMapper.class).insertUser(user);
    }

    public int deleteUser(int id) {
    
    
        return getSqlSession().getMapper(UserMapper.class).deleteUser(id);
    }
}

4.5测试

public class MyTest {
    
    
    @Test
    public void test(){
    
    
        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);
        }
    }
}

我们发现在没有事务的时候测试失败但是依然可以插进数据，但是却删除不了数据。这不是我们想看到的，要么成功要么失败。
所以我们需要在spring-dao.xml中配置事务

   <!-- 配置声明事务-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    </bean>


    <!-- 结合AOP实现事务得织入-->
    <!-- 配置事务通知 -->
    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <!-- 给那些方法配置事务-->
        <!-- 配置事务的传播特性-->
        <tx:attributes>
            <tx:method name="insert" propagation="REQUIRED"/>
            <tx:method name="delete" propagation="REQUIRED"/>
            <tx:method name="update" propagation="REQUIRED"/>
            <tx:method name="select" propagation="REQUIRED"/>
            <tx:method name="*" propagation="REQUIRED"/>
        </tx:attributes>
    </tx:advice>

    <!--配置事务切入-->
    <aop:config>
        <aop:pointcut id="txPointCut" expression="execution(* com.li.mapper.*.*(..))"/>
        <aop:advisor advice-ref="txAdvice" pointcut-ref="txPointCut"/>
    </aop:config>

删除四号用户，添加新用户五号

public class UserMapperImpl extends SqlSessionDaoSupport implements UserMapper {
    
    

    public List<User> selectUser() {
    
    
        User user = new User(5, "黄晓明", "123456");
        UserMapper mapper = getSqlSession().getMapper(UserMapper.class);
        mapper.insertUser(user);
        mapper.deleteUser(4);
        return mapper.selectUser();
    }

    public int insertUser(User user) {
    
    
        return getSqlSession().getMapper(UserMapper.class).insertUser(user);
    }

    public int deleteUser(int id) {
    
    
        return getSqlSession().getMapper(UserMapper.class).deleteUser(id);
    }

}

成功插入和删除解决了不一致性、完整性！

User{id=1, name=‘王麻子’, pwd=‘123456’}
User{id=2, name=‘张三’, pwd=‘123456’}
User{id=3, name=‘李四’, pwd=‘123456’}
User{id=5, name=‘黄晓明’, pwd=‘123456’}