Spring-Mybatis的业务实现的几种方式

程序员文章站 2022-05-24 20:18:28

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Spring-Mybatis的业务实现的三种方式

1、新建Maven项目

2、导入依赖

<dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
  <version>4.12</version>
  <scope>test</scope>
</dependency>
<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>5.1.23</version>
</dependency>
<dependency>
  <groupId>org.mybatis</groupId>
  <artifactId>mybatis</artifactId>
  <version>3.5.4</version>
</dependency>
<dependency>
  <groupId>org.mybatis</groupId>
  <artifactId>mybatis-spring</artifactId>
  <version>1.3.1</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-jdbc</artifactId>
  <version>5.0.8.RELEASE</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-context</artifactId>
  <version>5.0.8.RELEASE</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-core</artifactId>
  <version>5.0.8.RELEASE</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-test</artifactId>
  <version>5.0.8.RELEASE</version>
</dependency>

3、对应数据库建立实体类

Spring-Mybatis的业务实现的几种方式

无参构造函数、getter和setter还有toString方法

User.java：

@Component
public class User {
    private int uid;
    private String username;
    private String password;
    private int age;

    public User() {
    }

    @Override
    public String toString() {
        return "User{" +
                "uid=" + uid +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", age=" + age +
                '}';
    }

    public int getUid() {
        return uid;
    }

    public void setUid(int uid) {
        this.uid = uid;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public int getAge() {
        return age;
    }

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

4、编写Mapper接口

完成CRUD（增删改查）的需求

UserMapper.java：

public interface UserMapper {
    //查询所有用户
    List<User> selectAllUser();
    //根据id查询用户
    User selectUserById(int uid);
    //根据username模糊查询
    List<User> selectUserLikeUsername(String username);
    //新增用户（主键自增）
    int insertUser(User user);
}

5、编写Mapper接口对应的Mapper.xml文件

强烈建议Mapper接口文件和Mapper.xml文件在同一个包下

<namespace>对应接口的类限定名

对应的CRUD的标签的id对应Mapper接口的方法名字，返回值和传入参数也要对应

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="cn.yznu.mapper.UserMapper">
    <select id="selectAllUser" resultType="User">
        SELECT
            *
        FROM
            user
    </select>
    <select id="selectUserById" parameterType="integer" resultType="User">
        SELECT
            *
        FROM
            user
        WHERE
            uid=#{uid}
    </select>
    <select id="selectUserLikeUsername" parameterType="string" resultType="User">
        SELECT
            *
        FROM
            user
        WHERE
            username LIKE "%"#{username}"%"
    </select>
    <insert id="insertUser" parameterType="User"
            keyProperty="uid" useGeneratedKeys="true">
        INSERT INTO
            user
        (username,password,age)
        VALUES
        (#{username},#{password},#{age})
    </insert>
</mapper>

6、properties属性文件

db.properties:

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/表名?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8
jdbc.username=数据库用户名
jdbc.password=数据库密码

7、mybatis-config配置文件

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>
    <typeAliases>
        <package name="cn.yznu.pojo" />
    </typeAliases>
    <mappers>
        <mapper class="cn.yznu.mapper.UserMapper"/>
    </mappers>
</configuration>

8、spring-dao配置文件（建议单独写，再丢入Spring容器）

spring-config.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: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 http://www.springframework.org/schema/context/spring-context.xsd">
    <!--引入db.properties文件-->
    <context:property-placeholder location="classpath:db.properties"/>
    <!--    dataSource-->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="${jdbc.driver}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>
    <!--    sqlSessionFactory-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
    </bean>
    <!--    sqlSession-->
    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
        <constructor-arg index="0" ref="sqlSessionFactory"/>
    </bean>
</beans>

9、Spring容器配置文件

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: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 http://www.springframework.org/schema/context/spring-context.xsd">
    <import resource="spring-dao.xml"/>
    <context:component-scan base-package="cn.yznu.pojo"/>
</beans>

10、编写Mapper接口的实现类

写实现类的目的就是为了先将sqlSession对象获取到，然后再将SqlSession对象跟Mapper接口的CRUD方法封装，避免以后在业务里每次都还需要去获取SqlSession对象。

第一种方式、用@Autowired自动装配SqlSession对象

UserMapperImpl.java：

public class UserMapperImpl implements UserMapper {
    @Autowired
    SqlSession sqlSession;
    @Override
    public List<User> selectAllUser() {
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        return mapper.selectAllUser();
    }

    @Override
    public User selectUserById(int uid) {
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        return mapper.selectUserById(uid);
    }

    @Override
    public List<User> selectUserLikeUsername(String username) {
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        return mapper.selectUserLikeUsername(username);
    }

    @Override
    public int insertUser(User user) {
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        return mapper.insertUser(user);
    }
}

然后再给UserMapper接口和UserMapperImpl实现类的头上添加`@component`注解并且在spring容器里添加component扫描，让spring能够托管它们：

@Component
public interface UserMapper {

@Component
public class UserMapperImpl implements UserMapper {

<?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 http://www.springframework.org/schema/context/spring-context.xsd">
    <import resource="spring-dao.xml"/>
    <context:component-scan base-package="cn.yznu.mapper"/>
    <context:component-scan base-package="cn.yznu.pojo"/>
</beans>

测试：

UserMapperTest.java：

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"/applicationContext.xml"})
public class UserMapperTest {
    @Autowired
    UserMapper userMapper;
    @Autowired
    User user;
    @Test
    public void selectAllUser() {
        List<User> userList = userMapper.selectAllUser();
        System.out.println(userList);
    }

    @Test
    public void selectUserById() {
        User user = userMapper.selectUserById(1);
        System.out.println(user);
    }

    @Test
    public void selectUserLikeUsername() {
        List<User> userList = userMapper.selectUserLikeUsername("q");
        System.out.println(userList);
    }

    @Test
    public void insertUser() {
        user.setUsername("测试");
        userMapper.insertUser(user);
    }
}

因为UserMapper的接口和它的实现还有User都被我们丢到了spring容器，所以用@Autowired就可以直接用了，同时因为UserMapperImpl里面我们已经将sqlSession跟CRUD封装起来了，所以在测试里就不需要获取sqlSession对象了。

总结：在接口的实现类里，用Autowired获取到sqlSession对象，再返回sqlSession.getMapper()里的相应方法

第二种方式、在实现里用SqlSessionTemplate获取到sqlSess对象

去掉刚刚给UserMapper和UserMapperImpl头上加的@Component注解

再把刚刚的UserMapperImpl.java改成这样：

public class UserMapperImpl implements UserMapper {
    private SqlSessionTemplate sqlSession;
    public void setSqlSession(SqlSessionTemplate sqlSession){
        this.sqlSession=sqlSession;
    }
    @Override
    public List<User> selectAllUser() {
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        return mapper.selectAllUser();
    }

    @Override
    public User selectUserById(int uid) {
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        return mapper.selectUserById(uid);
    }

    @Override
    public List<User> selectUserLikeUsername(String username) {
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        return mapper.selectUserLikeUsername(username);
    }

    @Override
    public int insertUser(User user) {
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        return mapper.insertUser(user);
    }
}

用SqlSessionTemplate获取sqlSession对象，再写一个setSqlSession方法

再到applicationContext容器里给这个setSqlSession注入SqlSession：

去掉刚刚的<context:component-scan base-package="cn.yznu.mapper"/>

<?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 http://www.springframework.org/schema/context/spring-context.xsd">
    <import resource="spring-dao.xml"/>
    <context:component-scan base-package="cn.yznu.pojo"/>
    <bean id="UserMapper" class="cn.yznu.mapper.UserMapperImpl">
        <property name="sqlSession" ref="sqlSession"/>
    </bean>
</beans>

测试：

UserMapperTest.java:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"/applicationContext.xml"})
public class UserMapperTest {
    @Autowired
    UserMapper userMapper;
    @Autowired
    User user;
    @Test
    public void selectAllUser() {
        List<User> userList = userMapper.selectAllUser();
        System.out.println(userList);
    }

    @Test
    public void selectUserById() {
        User user = userMapper.selectUserById(1);
        System.out.println(user);
    }

    @Test
    public void selectUserLikeUsername() {
        List<User> userList = userMapper.selectUserLikeUsername("q");
        System.out.println(userList);
    }

    /*@Test
    public void insertUser() {
        user.setUsername("测试");
        userMapper.insertUser(user);
    }*/
}

因为刚刚我们的UserMapperImpl里已经跟SqlSession封装好了，并且也在applicationContext容器中注入了，所以我们就可以直接在业务或者测试里面直接用@Autowired自动装配UserMapper对象了。

第三种方式、用实现类继承SqlSessionSupport类再获取sqlSession对象

继承SqlSessionSupport类之后，就可以直接使用getSqlSession()方法获得sqlSession对象了

public class UserMapperImpl extends SqlSessionDaoSupport implements UserMapper  {
    @Override
    public List<User> selectAllUser() {
        UserMapper mapper = getSqlSession().getMapper(UserMapper.class);
        return mapper.selectAllUser();
    }

    @Override
    public User selectUserById(int uid) {
        UserMapper mapper = getSqlSession().getMapper(UserMapper.class);
        return mapper.selectUserById(uid);
    }

    @Override
    public List<User> selectUserLikeUsername(String username) {
        UserMapper mapper = getSqlSession().getMapper(UserMapper.class);
        return mapper.selectUserLikeUsername(username);
    }

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

要在Spring容器里给UserMapper注入SqlSessionFactory

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: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 http://www.springframework.org/schema/context/spring-context.xsd">
    <import resource="spring-dao.xml"/>
    <context:component-scan base-package="cn.yznu.pojo"/>
    <bean id="UserMapper" class="cn.yznu.mapper.UserMapperImpl">
        <property name="sqlSessionFactory" ref="sqlSessionFactory"/>
    </bean>
</beans>

测试：

UserMapperTestjava

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"/applicationContext.xml"})
public class UserMapperTest {
    @Autowired
    UserMapper userMapper;
    @Autowired
    User user;
    @Test
    public void selectAllUser() {
        List<User> userList = userMapper.selectAllUser();
        System.out.println(userList);
    }

    @Test
    public void selectUserById() {
        User user = userMapper.selectUserById(1);
        System.out.println(user);
    }

    @Test
    public void selectUserLikeUsername() {
        List<User> userList = userMapper.selectUserLikeUsername("q");
        System.out.println(userList);
    }

    /*@Test
    public void insertUser() {
        user.setUsername("测试");
        userMapper.insertUser(user);
    }*/
}

由于我们在实现类里继承了sqlSessionSupport类然后调用getSqlSession()方法获取到了sqlSession对象，并且在Spring容器里也注入了SqlSessionFactory，所以我们就可以直接在测试或者业务里用@Autowired装配UserMapper对象

其中，第二种方式和第三种方式都是官网提到的方式，官网更推荐第三种：

http://mybatis.org/spring/zh/sqlsession.html

Spring-Mybatis的业务实现的几种方式

总结：

都是为了解耦而将sqlSession跟Mapper接口的CRUD封装，然后交给Spring容器管理，再在业务或者测试里用@Autowired自动装配就好了

Spring-Mybatis的业务实现的几种方式

Spring-Mybatis的业务实现的三种方式

1、新建Maven项目

2、导入依赖

3、对应数据库建立实体类

4、编写Mapper接口

5、编写Mapper接口对应的Mapper.xml文件

6、properties属性文件

7、mybatis-config配置文件

8、spring-dao配置文件（建议单独写，再丢入Spring容器）

9、Spring容器配置文件

10、编写Mapper接口的实现类

第一种方式、用@Autowired自动装配SqlSession对象

UserMapperImpl.java：

然后再给UserMapper接口和UserMapperImpl实现类的头上添加`@component`注解并且在spring容器里添加component扫描，让spring能够托管它们：

测试：

总结：在接口的实现类里，用Autowired获取到sqlSession对象，再返回sqlSession.getMapper()里的相应方法

第二种方式、在实现里用SqlSessionTemplate获取到sqlSess对象

第三种方式、用实现类继承SqlSessionSupport类再获取sqlSession对象

总结：

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Spring-Mybatis的业务实现的几种方式

Spring-Mybatis的业务实现的三种方式

1、新建Maven项目

2、导入依赖

3、对应数据库建立实体类

4、编写Mapper接口

5、编写Mapper接口对应的Mapper.xml文件

6、properties属性文件

7、mybatis-config配置文件

8、spring-dao配置文件（建议单独写，再丢入Spring容器）

9、Spring容器配置文件

10、编写Mapper接口的实现类

第一种方式、用@Autowired自动装配SqlSession对象

UserMapperImpl.java：

然后再给UserMapper接口和UserMapperImpl实现类的头上添加@component注解并且在spring容器里添加component扫描，让spring能够托管它们：

测试：

总结：在接口的实现类里，用Autowired获取到sqlSession对象，再返回sqlSession.getMapper()里的相应方法

第二种方式、在实现里用SqlSessionTemplate获取到sqlSess对象

第三种方式、用实现类继承SqlSessionSupport类再获取sqlSession对象

总结：

PHP自然语言倒序的具体实现方式_PHP教程

静态页面也可以实现预览 列表不同的显示方式[原创]_javascript技巧

php生成二维码的几种方式

最全总结！聊聊 Python 发送邮件的几种方式

获取类的类对象的几种方式

php 递归函数的三种实现方式，php递归函数三种

Jquery 在页面加载后执行的几种方式_jquery

Shell实现程序造死循环的几种方法示例

php生成二维码的几种方式整理及使用实例_PHP

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然后再给UserMapper接口和UserMapperImpl实现类的头上添加`@component`注解并且在spring容器里添加component扫描，让spring能够托管它们：

静态页面也可以实现预览列表不同的显示方式[原创]_javascript技巧