Spring（四）spring整合mybatis框架

1、整合思想

使用Spring的ioc技术，把mybatis框架中的对象都交给spring创建和管理。Spring是容器，包含项目中的各种对象，例如：Service、Dao、工具类等对象。开发人员从spring中获取对象，就不用同时面对两个或多个框架，只需面对一个spring框架进行开发即可。

2、实现步骤

在pom文件中加入Spring依赖、Mybatis依赖、Spring和Mybayis整合依赖、druid连接池依赖等
编写数据库对应实体类、接口、mapper文件、service层文件等
Spring主配置文件
Mybatis配置文件

3、整合实现示例

着重看代码中注释。

数据库字段
实体类Student

public class Student {
   
    private Integer id;
    private String name;
    private String email;
    private Integer age;

    public Student() {
   }

    public Student(Integer id, String name, String email, Integer age) {
   
        this.id = id;
        this.name = name;
        this.email = email;
        this.age = age;
    }

    public void setId(Integer id) {
   
        this.id = id;
    }

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

    public void setEmail(String email) {
   
        this.email = email;
    }

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

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

接口StudentDao

public interface StudentDao {
   
    int insertStudent(Student student);     //插入数据
    List<Student> selectStudent();      //查询表中数据
}

Mapper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="cn.krain.dao.StudentDao">
    <!--在mybatis配置文件中已经通过typeAliases设置了别名， 因此resultType可直接使用student-->
    <select id="selectStudent" resultType="student">
        select * from student order by id desc
    </select>

    <insert id="insertStudent">
        insert into student values (#{id}, #{name}, #{email}, #{age})
    </insert>
</mapper>

StudentService

public interface StudentService {
   
    int addStudent(Student student);
    List<Student> selectStudent();
}

StudentServiceImpl

Service层，实现StudentService接口。

public class StudentServiceImpl implements StudentService {
   

    private StudentDao studentDao = null;

    public StudentServiceImpl(StudentDao studentDao) {
   
        this.studentDao = studentDao;
    }

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

    @Override
    public int addStudent(Student student) {
   
        int num = studentDao.insertStudent(student);
        return num;
    }

    @Override
    public List<Student> selectStudent() {
   
        List<Student> list = null;
        list = studentDao.selectStudent();
        return list;
    }
}

Spring.xml

使用Druid数据库连接池，DruidGitHub地址

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

    <!--使用druid数据库连接池-->
    <!--声明数据源对象-->
    <bean id="myDataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
        <!--使用set注入为属性赋值-->
        <property name="url" value="jdbc:mysql://localhost:3306/DB_Name"/><!--setURL()-->
        <property name="username" value=""/>
        <property name="password" value=""/>
        <property name="maxActive" value=""/>   <!--同时存在的数据库连接池最大个数-->
    </bean>

    <!--声明的是Mybatis中提供的SqlSessionFactoryBean类， 在这个类的内部创建SqlSessionFactory对象-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!--使用set注入，将数据库连接池赋给dataSource-->
        <property name="dataSource" ref="myDataSource"/>
        <!--告诉spring Mybatis主配置文件的位置， 使用configLocation的属性Resource类型读取Mybatis主配置文件-->
        <property name="configLocation" value="classpath:Mybatis.xml"/>
    </bean>

    <!--创建dao对象-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!--指定SqlSessionFactory对象的id-->
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
        <!--指定dao类的包名，spring会扫描该包下所有的dao接口， 使每个接口都执行getMapper()，获取dao对象 将dao对象放入spring容器中，对象名默认为接口名首字母小写-->
        <property name="basePackage" value="cn.krain.dao"/>
    </bean>

    <!--创建service对象-->
    <bean id="studentService" class="cn.krain.service.Impl.StudentServiceImpl">
        <!--使用set注入，为studentServiceImpl中的studentDao属性赋值-->
        <property name="studentDao" ref="studentDao"/>
    </bean>
</beans>

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>
    <!--为实体类设置别名-->
    <typeAliases>
        <!--name：实体类所在的包名 批量处理，自动起别名，名称为类名首字母小写-->
        <package name="cn.krain.domain"/>
    </typeAliases>

    <!--指定Sql映射文件（SQL Mapper）-->
    <mappers>
        <package name="cn.krain.dao"/>
    </mappers>
</configuration>

测试类Test

public class MyTest {
   

    @Test
    public void Test01(){
      //输出所有创建的对象
        String config = "applicationContext.xml";
        ApplicationContext ac = new ClassPathXmlApplicationContext(config);
        String names[] = ac.getBeanDefinitionNames();
        for(String name:names){
   
            System.out.println("创建的对象："+name);
        }
    }

    @Test
    public void TestServiceSelect(){
       //查询所有数据
        String config = "applicationContext.xml";
        ApplicationContext ac = new ClassPathXmlApplicationContext(config);
        StudentService service = (StudentService) ac.getBean("studentService");
        List<Student> list = service.selectStudent();
        for (Student st:list){
   
            System.out.println(st);
        }
    }

    @Test
    public void TestServiceInsert(){
       //插入数据
        String config = "applicationContext.xml";
        ApplicationContext ac = new ClassPathXmlApplicationContext(config);
        StudentService service = (StudentService) ac.getBean("studentService");
        Student student = new Student();
        student.setId(7);
        student.setName("khan");
        student.setEmail("khan@qq.com");
        student.setAge(34);
        int num = service.addStudent(student);
        System.out.println(num);
    }
}