Spring(四)—— Spring-Mybatis整合


上一节介绍了jdbcTemplate,但是它的手动映射让人感觉很麻烦,这节主要讲述Spring提供的另一种dao层解决方案,即使用Spring-Mybatis整合框架,这也是我学的第一个整合框架;

整合的思路:将SqlSessionFactory交给Spring管理;

使用步骤:

  1. 引入依赖;
  2. 创建bean类,dao层、service层、controller层相关的类;
  3. 创建Mybatis的xml配置文件、Mapper的配置文件、Spring的配置文件;
  4. 使用;

一 、引入依赖

需要引入Spring-Mybatis整合的依赖包、和Mybatis的依赖包,(当然,还有Spring的基本依赖包,前面说过,这只写需要新添加的):

       <!--mybatis和spring整合包-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>1.3.0</version>
        </dependency>

        <!--mybatis-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.1</version>
        </dependency>

Student表如下:
在这里插入图片描述

第一种方式

先来介绍这一种:

二、创建相关的类

创建对应的bean类:

public class Student {
    private int id;
    private String name;
    private String sex;
    private int age;

    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 getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                ", age=" + age +
                '}';
    }
}

Mapper接口:

public interface StudentMapper {
    public Student getStudentById(int id);
}

dao层对象:

public class StudentDao {
    private SqlSessionFactory sqlSessionFactory;

    public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) {
        this.sqlSessionFactory = sqlSessionFactory;
    }

    public Student getStudentBean(int id) {
        //获取sqlSession实例
        SqlSession sqlSession = sqlSessionFactory.openSession();
        Student student = (Student) sqlSession.selectOne("com.tulun6.dao.StudentMapper.getStudentById", id);
        return student;
    }
}

这个dao层类还可以这样写,更简单:

public class StudentDao extends SqlSessionDaoSupport {
    public Student getStudentBean(int id) {
        //获取sqlSession实例
        SqlSession sqlSession = this.getSqlSession();
        Student student = (Student) sqlSession.selectOne("com.tulun6.dao.StudentMapper.getStudentById", id);
        return student;
    }
}

因为SqlSessionDaoSupport类里面本身就有SqlSessionFactory属性,并提供了set方法,所以直接继承拿人家的用就好了;

service层:

public class StudentService {
    private StudentDao studentDao;

    public void setStudentDao(StudentDao studentDao) {
        this.studentDao = studentDao;
    }

    public Student getStudentBean(int id) {
        return studentDao.getStudentBean(id);
    }
}

controller层:

public class StudentController {
    private StudentService studentService;

    public void setStudentService(StudentService studentService) {
        this.studentService = studentService;
    }

    public Student getStudentById(int id) {
        return studentService.getStudentBean(id);
    }
}

三、创建相关的配置文件

然后就是配置文件,StudentMapper.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.tulun6.dao.StudentMapper">
    <select id="getStudentById" parameterType="int" resultType="com.tulun6.bean.Student">
        select * from student where id = #{id}
    </select>
</mapper>

mybatis的配置文件,mybatis.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>
    <!--映射-->
    <!--<mappers>
        <mapper resource="spring-mybatis整合/StudentMapper.xml"/>
    </mappers>-->
</configuration>

其实更多的时候,我们会把映射文件写在mybatis的配置文件里面,这样可以减少对Spring配置文件的依赖,但这一节为了介绍如何在Spring里面配置映射,就没在这儿写(就是注释掉的那部分语句,但是要知道,写在这儿也是可以的,只是Spring关于映射的语句就不能写了,不然有两个,它就不知道怎么办了,就会报错),下面就是Spring的配置文件spring-mybatis.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:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
      http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
      http://www.springframework.org/schema/context
      http://www.springframework.org/schema/context/spring-context-3.0.xsd
      http://www.springframework.org/schema/aop
      http://www.springframework.org/schema/aop/spring-aop.xsd">

    <!--配置数据源 通过连接池c3p0来操作-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <!--配置数据连接的核心配置-->
        <property name="driverClass" value="com.mysql.jdbc.Driver"/>
        <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/mybatis"/>
        <property name="user" value="root"/>
        <property name="password" value="123456"/>
    </bean>

    <!--创建SqlSessionFactory对象 路径是整合包里面的SqlSessionFactoryBean的全路径-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!--数据库的连接配置-->
        <property name="dataSource" ref="dataSource"/>
        <!--配置Mybatis的XML文件的路径-->
        <property name="configLocation" value="classpath:spring-mybatis整合/mybatis.xml"/>
        <!--配置Mapper的xml文件-->
        <!--================标记==========================-->
        <property name="mapperLocations">
            <list>
                <value>spring-mybatis整合/StudentMapper.xml</value>
            </list>
        </property>
        <!--================标记==========================-->
    </bean>

    <!--创建Controller层对象-->
    <bean id="dao" class="com.tulun6.dao.StudentDao">
        <!--注入service层对象作为属性-->
        <property name="sqlSessionFactory" ref="sqlSessionFactory"/>
    </bean>

    <!--创建Service层对象-->
    <bean id="service" class="com.tulun6.service.StudentService">
        <!--注入service层对象作为属性-->
        <property name="studentDao" ref="dao"/>
    </bean>

    <!--创建Controller层对象-->
    <bean id="controller" class="com.tulun6.controller.StudentController">
        <!--注入service层对象作为属性-->
        <property name="studentService" ref="service"/>
    </bean>
</beans>

上面spring的配置文件里面我打标记的那部分语句和mybatis里面的映射语句只能存在一个!!

四、使用

public class TestDemo1 {
    @Test
    public void test() {
        ApplicationContext context = new ClassPathXmlApplicationContext("spring-mybatis整合/spring-mybatis.xml");
        StudentController studentController = (StudentController)context.getBean("controller");
        Student student = studentController.getStudentById(1);
        System.out.println(student);
    }
}

在这里插入图片描述

第二种方式

这种写法就是使用Mapper代理对象进行映射开发,就像在Mybatis框架里面一样,我们要通过SqlSessionFactory最终得到Mapper对象,然后使用一样:
在这里插入图片描述
bean层类不用改,dao层的类也不用改,因为不用dao层的对象了,service需要改一下(属性是Mapper接口类型的):

public class StudentService1 {
    private StudentMapper studentMapper;

    public void setStudentMapper(StudentMapper studentMapper) {
        this.studentMapper = studentMapper;
    }

    public Student getStudentBean(int id) {
        return studentMapper.getStudentById(id);
    }
}

那对应的controller层类也就需要改一下了:

public class StudentController1 {
    private StudentService1 studentService1;

    public void setStudentService1(StudentService1 studentService1) {
        this.studentService1 = studentService1;
    }

    public Student getStudentById(int id) {
        return studentService1.getStudentBean(id);
    }
}

三个配置文件,需要该spring的配置文件(改的是我写标记的那部分):

<?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:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
      http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
      http://www.springframework.org/schema/context
      http://www.springframework.org/schema/context/spring-context-3.0.xsd
      http://www.springframework.org/schema/aop
      http://www.springframework.org/schema/aop/spring-aop.xsd">

    <!--配置数据源 通过连接池c3p0来操作-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <!--配置数据连接的核心配置-->
        <property name="driverClass" value="com.mysql.jdbc.Driver"/>
        <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/mybatis"/>
        <property name="user" value="root"/>
        <property name="password" value="123456"/>
    </bean>

    <!--创建SqlSessionFactory对象 路径是整合包里面的SqlSessionFactoryBean的全路径-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!--数据库的连接配置-->
        <property name="dataSource" ref="dataSource"/>
        <!--配置Mybatis的XML文件的路径-->
        <property name="configLocation" value="classpath:spring-mybatis整合/mybatis.xml"/>
        <!--配置Mapper的xml文件-->
        <property name="mapperLocations">
            <list>
                <value>spring-mybatis整合/StudentMapper.xml</value>
            </list>
        </property>
    </bean>

    <!--===========================标记=========================================-->
    <!--使用Mapper代理对象进行映射开发 class即MapperFactoryBean-->
    <bean id="studentMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
        <!--mapperInterface指定mapper接口-->
        <property name="mapperInterface" value="com.tulun6.dao.StudentMapper"/>
        <!--指定sqlSessionFactory-->
        <property name="sqlSessionFactory" ref="sqlSessionFactory"/>
    </bean>

    <!--创建Service层对象-->
    <bean id="service" class="com.tulun6.service.StudentService1">
        <!--注入service层对象作为属性-->
        <property name="studentMapper" ref="studentMapper"/>
    </bean>

    <!--创建Controller层对象-->
    <bean id="controller1" class="com.tulun6.controller.StudentController1">
        <!--注入service层对象作为属性-->
        <property name="studentService1" ref="service"/>
    </bean>
    <!--===========================标记=========================================-->
</beans>

测试:

public class TestDemo2 {
        @Test
        public void test() {
            ApplicationContext context = new ClassPathXmlApplicationContext("spring-mybatis整合/spring-mybatis-plus.xml");
            StudentController1 studentController1 = (StudentController1) context.getBean("controller1");
            Student student = studentController1.getStudentById(1);
            System.out.println(student);
        }
}

在这里插入图片描述

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