java - Spring + MyBatis 异常: Mapped Statements collection does not contain value for

Question

我在执行这个应用程序时遇到了这个异常:

public class MainApp {

    private static ApplicationContext context = null;
    static SqlSession session = null;

    public static void main(String[] args) throws IllegalArgumentException {
        try {

            context = new FileSystemXmlApplicationContext(
                                            "src/main/webapp/WEB-INF/applicationContext.xml");
            session = (SqlSession) context.getBean("sqlSession");
            OrderMapper orderMapper = session.getMapper(OrderMapper.class);
            int orderQuantity = orderMapper.getAllOrder().size();
            System.out.println("Order quantity: " + orderQuantity);
            session.commit();
            session.close();
        } catch (Throwable e) {
            e.printStackTrace();
        } 
    }
}

这是我的 OrderMapper 界面:

public interface OrderMapper {

    public List<Order> getAllOrder();
}

OrderMapper.xml

<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
 "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.thonglm1.spring.mappers.OrderMapper">

    <resultMap id="result" type="order">
        <result property="orderId" column="cartid" />
        <result property="type" column="type" />
        <result property="saleId" column="saleId" />
        <result property="status" column="status" />
        <result property="info1" column="info1" />
        <result property="info2" column="info2" />
        <result property="info3" column="info3" />
    </resultMap>

    <select id="getAllOrder" resultMap="result">
        select cartId, type,
        info1
        from TRAIN_ORDER;
    </select>
</mapper>

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:security="http://www.springframework.org/schema/security"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="
        http://www.springframework.org/schema/aop 
        http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
        http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-2.5.xsd
        http://www.springframework.org/schema/tx 
        http://www.springframework.org/schema/tx/spring-tx-2.5.xsd"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

    <bean id="dataSource"
        class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="oracle.jdbc.OracleDriver" />
        <property name="url" value="jdbc:oracle:thin:@172.21.8.62:1521:SHESVDEV" />
        <property name="username" value="test" />
        <property name="password" value="test" />
    </bean>

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="configLocation" value="src/main/webapp/WEB-INF/mybatis-config.xml" />
    </bean>

    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
        <constructor-arg index="0" ref="sqlSessionFactory" />
    </bean>

    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <property name="basePackage" value="com.thonglm1.spring.mappers" />
    </bean>

    <bean id="transactionManager"
        class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>

</beans>

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>
        <typeAlias type="com.thonglm1.spring.domain.Order" alias="order" />
    </typeAliases>
    <mappers>
        <package name="com.thonglm1.spring.mappers" />
    </mappers>
</configuration>

最后，我得到了异常:

java.lang.IllegalArgumentException: Mapped Statements collection does not contain value for com.thonglm1.spring.mappers.OrderMapper.getAllOrder at org.apache.ibatis.session.Configuration$StrictMap.get(Configuration.java:672) at org.apache.ibatis.session.Configuration.getMappedStatement(Configuration.java:507) at org.apache.ibatis.session.Configuration.getMappedStatement(Configuration.java:500) at org.apache.ibatis.binding.MapperMethod.setupCommandType(MapperMethod.java:240) at org.apache.ibatis.binding.MapperMethod.(MapperMethod.java:71) at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:39) at $Proxy6.getAllOrder(Unknown Source) at MainApp.main(MainApp.java:21)

还有一件事，因为我对此很陌生，我的代码中是否有任何不良做法？或者有什么我可以改进的吗？请随时发表评论，我将不胜感激。

Answer 1

您在哪里指定映射器 XML 位置？您可以将其添加到 sqlSessionFactory 的属性 mapperLocations 中。由于您使用的是maven。我认为最好将映射器 XML 文件移动到 resources 目录内的文件夹中。当您添加更多数量的 XML 文件时，它将更容易维护。我认为下面的文件夹结构是有意义的，因为所有相关的东西都与所有 JDBC 相关的东西组合在一个包下，子包作为域、映射器、服务接口(interface)和服务接口(interface)实现。

在这种情况下，由于在编译/打包期间所有配置都在 WEB-INF/classes 目录下，这也是一个类路径，因此此应用程序配置应该保持良好。

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:security="http://www.springframework.org/schema/security"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="
        http://www.springframework.org/schema/aop 
        http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
        http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-2.5.xsd
        http://www.springframework.org/schema/tx 
        http://www.springframework.org/schema/tx/spring-tx-2.5.xsd"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

    <bean id="dataSource"
        class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="oracle.jdbc.OracleDriver" />
        <property name="url" value="jdbc:oracle:thin:@172.21.8.62:1521:SHESVDEV" />
        <property name="username" value="test" />
        <property name="password" value="test" />
    </bean>

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
       <property name="configLocation" value="classpath:config/mybatis-config.xml" />
    <property name="mapperLocations" value="classpath*:sqlmap/*.xml" />
    </bean>

    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
        <constructor-arg index="0" ref="sqlSessionFactory" />
    </bean>

    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <property name="basePackage" value="com.thonglm1.spring.mappers" />
    </bean>

    <bean id="transactionManager"
        class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>

</beans>

而mybatis-config.xml，domain包中的别名默认都是首字母小的类名。

?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="com.thonglm1.spring.domain" />
    </typeAliases>       
</configuration>