289 lines
8.2 KiB
Markdown
289 lines
8.2 KiB
Markdown
# 第十章：Spring 和 MyBatis 的整合
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基于SSM的用户管理系统的设计与实现
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## 基于传统的DAO方式的整合
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#### 0.导包
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mybatis mybatis-spring spring mysql spring-tx spring-jdbc commons-dbcp2
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```java
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<dependency>
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<groupId>org.mybatis</groupId>
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<artifactId>mybatis</artifactId>
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<version>3.4.2</version>
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</dependency>
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<dependency>
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<groupId>org.mybatis</groupId>
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<artifactId>mybatis-spring</artifactId>
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<version>1.3.1</version>
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</dependency>
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<dependency>
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<groupId>org.springframework</groupId>
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<artifactId>spring-context</artifactId>
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<version>4.3.6.RELEASE</version>
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</dependency>
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<dependency>
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<groupId>org.apache.commons</groupId>
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<artifactId>commons-dbcp2</artifactId>
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<version>2.1.1</version>
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</dependency>
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<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
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<dependency>
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<groupId>mysql</groupId>
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<artifactId>mysql-connector-java</artifactId>
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<version>8.0.28</version>
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</dependency>
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<dependency>
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<groupId>junit</groupId>
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<artifactId>junit</artifactId>
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<version>4.12</version>
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<scope>compile</scope>
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</dependency>
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<dependency>
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<groupId>org.springframework</groupId>
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<artifactId>spring-jdbc</artifactId>
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<version>4.3.6.RELEASE</version>
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</dependency>
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<dependency>
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<groupId>org.springframework</groupId>
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<artifactId>spring-tx</artifactId>
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<version>4.3.6.RELEASE</version>
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</dependency>
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```
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#### 1.准备数据
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mybatis 中的 t_customer
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#### 2.创建实体类
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```java
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//在com.gzh.domain下创建
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private int id;
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private String username;
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private String jobs;
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private String phone;
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//利用 getter ， setter 和 toString 方法生成代码
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```
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#### 3.在resources下创建CustomerMapper.xml文件
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```java
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<!-- 1.根据id查找用户-->
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<select id="findCustomerById" parameterType="int" resultType="com.gzh.domain.Customer">
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select * from t_customer where id=#{id}
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</select>
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</mapper>
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```
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#### 4.在resources下创建mybatis-config.xml文件
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```java
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<!--加载Mapper文件-->
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<mappers>
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<mapper resource="CustomerMapper.xml"/>
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</mappers>
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```
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#### 5.创建DAO层接口和实现类
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```java
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//在com.gzh.dao包下创建接口
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public interface CustomerDao {
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Customer findCustomerById(int id);
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}
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```
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```java
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//在com.gzh.dao.impl包下创建实现类
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public class CustomerDaoImpl extends SqlSessionDaoSupport implements CustomerDao {
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@Override
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public Customer findCustomerById(int id){
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Customer o = getSqlSession().selectOne("CustomerMapper.findCustomerById", id);
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return o;
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}
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}
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```
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#### 6.在resources下创建applicationContext.xml文件
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```java
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<!-- 1.连接数据库-->
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<bean id="dataSource" class="org.apache.commons.dbcp2.BasicDataSource">
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<property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
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<property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>
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<property name="username" value="root"/>
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<property name="password" value="8520"/>
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</bean>
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<!-- 2.加载MyBAtis的配置文件-->
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<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
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<property name="dataSource" ref="dataSource"/>
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<property name="configLocation" value="classpath:mybatis-config.xml"/>
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</bean>
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<!-- 3.创建接口对象-->
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<bean id="customerDao" class="com.gzh.dao.impl.CustomerDaoImpl">
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<property name="sqlSessionFactory" ref="sqlSessionFactory"/>
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</bean>
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```
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#### 7.测试
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```java
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//在com.gzh.domain包下创建测试类
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@Test
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public void findCustomerByIdTest(){
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ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
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CustomerDao customerDao = (CustomerDao) applicationContext.getBean("customerDao");
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Customer customerById = customerDao.findCustomerById(1);
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System.out.println(customerById);
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}
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```
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## 基于Mapper方式的整合
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### 基于MapperFactoryBean的整合
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#### 0.导包
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与DAO方式导包数量相同
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#### 1.准备数据
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同上数据
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#### 2.创建实体类
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```java
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//在com.gzh.domain下创建
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private int id;
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private String username;
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private String jobs;
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private String phone;
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//利用 getter ， setter 和 toString 方法生成代码
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```
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#### 3.创建com.gzh.mapper. CustomerMapper接口文件
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```java
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public interface CustomerMapper {
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Customer findCustomerById(int i);
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}
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```
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#### 4.在resources下创建com->gzh->mapper->CustomerMapper.Xml文件
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com.gzh.mapper 文件夹要一个一个创建，才能保证是嵌套的
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```java
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<mapper namespace="com.gzh.mapper.CustomerMapper">
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<!--1.根据id查询客户信息-->
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<select id="findCustomerById" parameterType="int" resultType="com.gzh.domain.Customer">
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select * from t_customer where id=#{id}
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</select>
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</mapper>
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```
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#### 5.在resources下创建mybatis-config.xml文件
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```java
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<mappers>
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<mapper resource="com/gzh/mapper/CustomerMapper.xml"/>
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</mappers>
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```
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#### 6.在resources下创建applicationContext.xml文件
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```java
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<!-- 1.连接数据库-->
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<bean id="dataSource" class="org.apache.commons.dbcp2.BasicDataSource">
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<property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
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<property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>
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<property name="username" value="root"/>
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<property name="password" value="8520"/>
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</bean>
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<!-- 2.加载MyBAtis的配置文件-->
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<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
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<property name="dataSource" ref="dataSource"/>
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<property name="configLocation" value="classpath:mybatis-config.xml"/>
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</bean>
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<!-- 3.创建MapperFactoryBean类对象-->
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<bean id="factoryBean" class="org.mybatis.spring.mapper.MapperFactoryBean">
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<property name="mapperInterface" value="com.gzh.mapper.CustomerMapper"/>
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<property name="sqlSessionFactory" ref="sqlSessionFactory"/>
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</bean>
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```
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#### 7.测试
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```java
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@Test
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public void findCustomerById(){
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ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
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CustomerMapper factoryBean = (CustomerMapper) applicationContext.getBean("factoryBean");
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Customer customerById = factoryBean.findCustomerById(1);
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System.out.println(customerById);
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}
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```
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虽然使用Mapper接口编程的方式很简单，但是在具体使用时还是需要遵循以下规范。
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> (I)Mapper接口的名称和对应的Mapper.xml映射文件的名称必须一致。
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>
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> (2)Mapper,.xml文件中的namespace与Mapper接口的类路径相同（即接口文件和映射文件
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> 需要放在同一个包中)。
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>
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> (3)Mapper接口中的方法名和Mapper.xml中定义的每个执行语句的id相同。
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>
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> (4)Mapper接口中方法的输入参数类型要和Mapper,.xml中定义的每个sql的parameterType
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> 的类型相同。
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>
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> (5)Mapper接口方法的输出参数类型要和Mapper.xml中定义的每个sql的resultType的
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> 类型相同。
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只要遵循了这些开发规范，MyBatis就可以自动生成Mapper接口实现类的代理对象，从而
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简化我们的开发。
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### 基于MapperScannerConfigurer的整合
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在上面的基础上修改
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1.在 applicationContext 中注释以下代码
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```java
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<!-- 3.创建MapperFactoryBean类对象-->
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<bean id="factoryBean" class="org.mybatis.spring.mapper.MapperFactoryBean">
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<property name="mapperInterface" value="com.gzh.mapper.CustomerMapper"/>
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<property name="sqlSessionFactory" ref="sqlSessionFactory"/>
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</bean>
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```
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2.在 applicationContext 中添加以下代码
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```java
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<!-- 4.基于MapperScannerConfigurer的整合-->
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<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
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<property name="basePackage" value="com.gzh.mapper"/>
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</bean>
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```
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3.创建新的测试类
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```java
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@Test
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public void findCustomerById1(){
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ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
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CustomerMapper bean = applicationContext.getBean(CustomerMapper.class);
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Customer customerById = bean.findCustomerById(1);
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System.out.println(customerById);
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}
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```
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