mysql - Autowiring 时sqlSession为空(mybatis3，Spring5)

Question

我刚刚创建了一个项目，我正在尝试将数据插入到 mysql 中。

但是尝试插入行时 sqlSession 为空。

我使用“System.out.println”来检查 sqlSession 对象是否正确 Autowiring 。但是我发现 sqlSession 对象为空。

根上下文.xml

<bean id="dataSource" class="org.springframework.jdbc.datasource.SimpleDriverDataSource">
    <property name="driverClass" value="com.mysql.cj.jdbc.Driver" />
    <property name="url" value="jdbc:mysql://127.0.0.1:3306/test" />
    <property name="username" value="root" />
    <property name="password" value="ekehd#65" />
</bean>



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

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



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

mybatis配置

<!DOCTYPE configuration

  PUBLIC "-//mybatis.org//DTD Config 3.0//EN"

  "http://mybatis.org/dtd/mybatis-3-config.dtd">

<typeAliases>

    <typeAlias type="com.myproject.model.User" alias="user" />

</typeAliases>

<mappers>

    <mapper resource="com/myproject/mapper/user.xml" />

</mappers> 

映射器.xml

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

  PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"

  "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<insert id="insertUser" parameterType="user">
    insert into web_users 
    values(#{id}, #{password})
</insert>

Dao.java

public class UserDao {

@Autowired
private SqlSession session;


public int insertUser(User user) {
    System.out.println("session : "+session);
    String key = "com.myproject.mapper.user.insertUser";
    Map<String, String> map = new HashMap<String, String>();

    return session.insert(key, user);
}

}

Controller .java

    @RequestMapping(value = "/in", method = RequestMethod.GET)
public String home1(Locale locale, Model model) {
    logger.info("Welcome home! The client locale is {}.", locale);

    Date date = new Date();
    DateFormat dateFormat = DateFormat.getDateTimeInstance(DateFormat.LONG, DateFormat.LONG, locale);

    String formattedDate = dateFormat.format(date);

    model.addAttribute("serverTime", formattedDate );

    System.out.println("@@@@@@@@@@@@@@");
    UserDao dao = new UserDao();
    User user = new User();
    user.setId("idid");
    user.setPassword("pwpwpw");

    int result = dao.insertUser(user);
    //System.out.println("Result " +result);
    return "home";
}

以及错误日志

java.lang.NullPointerException
at com.myproject.dao.UserDao.insertUser(UserDao.java:23)
at com.myproject.HomeController.home1(HomeController.java:61)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:877)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:783)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:866)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:962)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1115)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThrea

Answer 1

我认为您不需要注入(inject)sqlSession来插入数据。您可以使用 org.mybatis.spring.mapper.MapperScannerConfigurer 扫描所有映射器接口(interface)。然后您可以调用映射器中的方法来插入数据。

这是我的 spring 配置

<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"
   xmlns:mvc="http://www.springframework.org/schema/mvc"
   xsi:schemaLocation="http://www.springframework.org/schema/beans
   http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
   http://www.springframework.org/schema/context 
   http://www.springframework.org/schema/context/spring-context.xsd 
   http://www.springframework.org/schema/mvc 
   http://www.springframework.org/schema/mvc/spring-mvc.xsd">
<context:component-scan base-package="com.henryxi"/>
<mvc:annotation-driven/>

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

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

<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
    <property name="driverClassName" value="com.mysql.jdbc.Driver">
    </property>
    <property name="url" value="jdbc:mysql://192.168.56.6:3306/test_db"/>
    <property name="username" value="root"/>
    <property name="password" value="123456"/>
</bean>

然后是mybatis配置

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE configuration
        PUBLIC "-//ibatis.apache.org//DTD Config 3.1//EN"
        "http://ibatis.apache.org/dtd/ibatis-3-config.dtd">
    <configuration>
        <properties>
            <property name="dialect" value="mysql"/>
        </properties>
</configuration>

对于整个项目，您可以看到 MyBatis Spring example