项目结构

pom依赖

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>org.example</groupId>
  <artifactId>testSpringMybatis</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>testSpringMybatis Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>

    <!-- 1.导入Spring相关的jar包 -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>4.3.18.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>4.3.18.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-beans</artifactId>
      <version>4.3.18.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context-support</artifactId>
      <version>4.3.18.RELEASE</version>
    </dependency>

    <!-- 导入mybatis的jar包 -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.37</version>
    </dependency>
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.4.6</version>
    </dependency>
    <dependency>
      <groupId>com.mchange</groupId>
      <artifactId>c3p0</artifactId>
      <version>0.9.5.2</version>
    </dependency>

    <!-- 配置日志信息-->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>1.2.17</version>
    </dependency>

    <!-- spring 整合 mybatis-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>1.3.0</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>4.3.18.RELEASE</version>
    </dependency>

  </dependencies>

  <build>
    <resources>
      <resource>
        <!-- 将Mapper的映射文件拷贝出来 -->
        <directory>src/main/java</directory>
        <includes>
          <include>**/*.xml</include>
        </includes>
        <filtering>true</filtering>
      </resource>
    </resources>
    <finalName>testSpringMybatis</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

mybatis配置文件

<?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>

    <!--配置db.properties  转移到spring中-->
    <!--<properties resource="db.properties" />-->
    <!-- 配置日志管理 -->
    <settings>
        <setting name="logImpl" value="STDOUT_LOGGING"/>
    </settings>

    <!-- 设置别名-->
    <typeAliases>
        <package name="com.test.pojo" />
    </typeAliases>

    <!-- 转移到spring配置文件中 -->
    <!--<environments default="development">-->
        <!--<environment id="development">-->
            <!--<transactionManager type="JDBC"/>-->
            <!--<dataSource type="POOLED">-->
                <!--<property name="driver" value="${driverClass}"/>-->
                <!--<property name="url" value="${url}"/>-->
                <!--<property name="username" value="${user}"/>-->
                <!--<property name="password" value="${password}"/>-->
            <!--</dataSource>-->
        <!--</environment>-->
    <!--</environments>-->

     <!--注册mapper文件-->
    <mappers>
       <package name="com.test.mapper" />
    </mappers>

</configuration>   

spring配置文件

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

    <!-- 1.扫描包中的注解 -->
    <context:component-scan base-package="com.test" />

    <!--导入db.properties文件-->
    <context:property-placeholder location="classpath:db.properties" />

    <!--创建了数据源 -->
    <bean id="comboPooledDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="${driverClass}" />
        <property name="jdbcUrl" value="${url}"/>
        <property name="user" value="${user}" />
        <property name="password" value="${password}" />
    </bean>

    <!--创建SqlSessionFactory对象 -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="comboPooledDataSource" />
        <property name="configLocation" value="classpath:sqlMapConfig.xml" />
    </bean>

</beans>

spring帮我们创建dao层

在spring配置文件中添加如下配置

<!-- 配置映射文件的扫描器 -->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <property name="basePackage" value="com.test.mapper"/>
</bean>

在service中注入itemsMapper

@Autowired
private ItemsMapper itemsMapper;

原来的dao层可以删除
mybatis配置文件中的注册mapper可以删除