Spring

ssm框架

发布日期: 2020-11-28

更新日期: 2020-11-29

文章字数: 1.5k

阅读时长: 8 分

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整合Mybatis

原有 Mybatis 实现

1.导入相关jar包

junit

      <dependency>
          <groupId>junit</groupId>
          <artifactId>junit</artifactId>
          <version>4.13</version>
      </dependency>

mybatis

      <dependency>
          <groupId>org.mybatis</groupId>
          <artifactId>mybatis</artifactId>
          <version>3.5.4</version>
      </dependency>

mysql-connector-java

      <dependency>
          <groupId>mysql</groupId>
          <artifactId>mysql-connector-java</artifactId>
          <version>5.1.47</version>
      </dependency>

Spring相关

      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-webmvc</artifactId>
          <version>5.3.1</version>
      </dependency>

aspectJ AOP 织入器

      <dependency>
          <groupId>org.aspectj</groupId>
          <artifactId>aspectjweaver</artifactId>
          <version>1.9.6</version>
      </dependency>

mybatis-spring整合包【重点】

      <dependency>
          <groupId>org.mybatis</groupId>
          <artifactId>mybatis-spring</artifactId>
          <version>2.0.6</version>
      </dependency>

spring-jdbc

      <!--        spring操作数据库，需要spring-jdbc-->
      <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-jdbc</artifactId>
          <version>5.3.1</version>
      </dependency>

配置Maven静态资源过滤问题！（pom.xml）

<!--在build中配置resources，防止资源导出失败-->
<build>
  <resources>
      <resource>
          <directory>src/main/java</directory>
          <includes>
              <include>**/*.properties</include>
              <include>**/*.xml</include>
          </includes>
          <filtering>true</filtering>
      </resource>
      <resource>
          <directory>src/main/resources</directory>
          <includes>
              <include>**/*.properties</include>
              <include>**/*.xml</include>
          </includes>
          <filtering>true</filtering>
      </resource>
  </resources>
</build>

2.编写实体类(使用lombok)

@Data
public class User {

    private int id;
    private String username;
    private String password;
}

3.编写核心配置文件(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>

    <!--    开启别名-->
    <typeAliases>
        <package name="com.allen.pojo"/>
    </typeAliases>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis02?useSSL=true&amp;useUnicode=true&amp;characterEncoding=utf8"/>
                <property name="username" value="root"/>
                <property name="password" value="1005"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <!--<mapper class="com.allen.mapper.UserMapper"/>-->
        <mapper resource="com/allen/mapper/UserMapper.xml"/>
    </mappers>

</configuration>

4.编写接口

public interface UserMapper {
    List<User> selectUser();
}

5.编写Mapper.xml

( 注意namespace，并且一定要在核心配置文件中注册，两种注册方式)

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.allen.mapper.UserMapper">

    <select id="selectUser" resultType="user">
        select * from user;
    </select>

</mapper>

6.测试

import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

/**
 * @author Allen
 * @date 2020/11/28 20:47
 */
public class MyTest {

    @Test
    public void test() throws IOException {
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);

        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        //为 true 则自动提交，commit
        SqlSession sqlSession = sqlSessionFactory.openSession(true);

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<User> users = mapper.selectUser();
        for (User user : users) {
            System.out.println(user);
        }

            sqlSession.close();     //关闭连接
    }

}

Mybatis整合（一）

在resource 包下新建 spring-dao.xml

1.编写数据源配置

    <!--    DataSource:使用Spring的数据源替换Mybatis的配置  c3p0 dbcp druid
        这里使用Spring提供的jdbc: org.springframework.jdbc.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/mybatis02?useSSL=true&amp;useUnicode=true&amp;characterEncoding=utf8"/>
            <property name="username" value="root"/>
            <property name="password" value="1005"/>
        </bean>

2.sqlSessionFactory

    <!--    SqlSessionFactory-->
    <!--配置SqlSessionFactory-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <!--关联Mybatis-->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <property name="mapperLocations" value="classpath:com/allen/mapper/*.xml"/>
        <!--        开启别名-->
        <!-- <property name="typeAliases" value="com.allen.pojo.User"/>-->
    </bean>

3.sqlSessionTemplate

    <!--注册sqlSessionTemplate , 关联sqlSessionFactory-->
    <!--SqlSessionTemplate就是我们使用的sqlSession-->
    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
        <!--只能通过构造器注入，因为没有 set 方法-->
        <constructor-arg index="0" ref="sqlSessionFactory"/>
    </bean>

4.需要给接口加实现类

在 mapper 包下新建 UserMapperImpl

package com.allen.mapper;

import com.allen.pojo.User;
import org.mybatis.spring.SqlSessionTemplate;

import java.util.List;

/**
 * @author Allen
 * @date 2020/11/28 21:34
 */
public class UserMapperImpl implements UserMapper {

    //sqlSession不用我们自己创建了，Spring来管理
    //原来使用的 sqlSession，现在统统换成 SqlSessionTemplate
    private SqlSessionTemplate sqlSession;

    public void setSqlSession(SqlSessionTemplate sqlSession) {
        this.sqlSession = sqlSession;
    }

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

5.将自己写的实现类注入到 Spring

在resource 包下新建 applicationContext.xml，可以把 spring-dao.xml 引入，然后注入实现类 UserMapperImpl。

<?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">

    <import resource="spring-dao.xml"/>

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

6.测试使用

测试只需要按 Spring 获取上下文即可，无需创建 sqlSession

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);
        }
    }

}

7.输出

User(id=1, username=mazu, password=asdf)
User(id=2, username=lis, password=123456)
User(id=3, username=wangw, password=123)
User(id=4, username=zhaol, password=123456)
User(id=6, username=wangzai, password=111223)
User(id=9, username=wangzai, password=1266666)

Mybatis整合（二）（默认自动提交和关闭）

默认自动提交和关闭，可查看 SqlSessionTemplate.class 的源码 190-221 行

public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
    SqlSession sqlSession = SqlSessionUtils.getSqlSession(SqlSessionTemplate.this.sqlSessionFactory, SqlSessionTemplate.this.executorType, SqlSessionTemplate.this.exceptionTranslator);

    Object unwrapped;
    try {
        Object result = method.invoke(sqlSession, args);
        if (!SqlSessionUtils.isSqlSessionTransactional(sqlSession, SqlSessionTemplate.this.sqlSessionFactory)) {
            sqlSession.commit(true);
        }

        unwrapped = result;
    } catch (Throwable var11) {
        unwrapped = ExceptionUtil.unwrapThrowable(var11);
        if (SqlSessionTemplate.this.exceptionTranslator != null && unwrapped instanceof PersistenceException) {
            SqlSessionUtils.closeSqlSession(sqlSession, SqlSessionTemplate.this.sqlSessionFactory);
            sqlSession = null;
            Throwable translated = SqlSessionTemplate.this.exceptionTranslator.translateExceptionIfPossible((PersistenceException)unwrapped);
            if (translated != null) {
                unwrapped = translated;
            }
        }

        throw (Throwable)unwrapped;
    } finally {
        if (sqlSession != null) {
            SqlSessionUtils.closeSqlSession(sqlSession, SqlSessionTemplate.this.sqlSessionFactory);
        }

    }

    return unwrapped;
}

dao继承Support类 , 直接利用 getSqlSession() 获得 , 然后直接注入SqlSessionFactory . 比起方式1 , 不需要管理SqlSessionTemplate , 而且对事务的支持更加友好 . 可跟踪源码查看

1.UserDaoImpl修改(新建UserDaoImpl2)

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

2.bean的注入

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

3.测试

public class MyTest {

    @Test
    public void test(){
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserMapper userMapper = context.getBean("userMapper2",UserMapper.class);
        List<User> users = userMapper.selectUser();
        for (User user : users) {
            System.out.println(user);
        }
    }

}

Hailong Gao

https://hlgao666.github.io/2020/11/28/Spring/整合Mybatis/

本博客所有文章除特別声明外，均采用 CC BY 4.0 许可协议。转载请注明来源 Hailong Gao !

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整合Mybatis

整合Mybatis

原有 Mybatis 实现

1.导入相关jar包

2.编写实体类(使用lombok)

3.编写核心配置文件(mybatis-config.xml)

4.编写接口

5.编写Mapper.xml

6.测试

Mybatis整合（一）

1.编写数据源配置

2.sqlSessionFactory

3.sqlSessionTemplate

4.需要给接口加实现类

5.将自己写的实现类注入到 Spring

6.测试使用

7.输出

Mybatis整合（二）（默认自动提交和关闭）

1.UserDaoImpl修改(新建UserDaoImpl2)

2.bean的注入

3.测试

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