Question

我有一个Spring Rest WS，然后需要实现myBatis到这个。我试过但是得到了错误。

以下是我的源代码。

从web.xml

开始

    <?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
      <display-name>SpringServiceJsonSample</display-name>
      <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
        <welcome-file>default.html</welcome-file>
        <welcome-file>default.htm</welcome-file>
        <welcome-file>default.jsp</welcome-file>
      </welcome-file-list>
      <servlet>
        <servlet-name>rest</servlet-name>
        <servlet-class> org.springframework.web.servlet.DispatcherServlet 
            </servlet-class>
        <load-on-startup>1</load-on-startup>
      </servlet>
      <servlet-mapping>
        <servlet-name>rest</servlet-name>
        <url-pattern>/*</url-pattern>
      </servlet-mapping>
      <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/ApplicationContext.xml
        </param-value>
      </context-param>
    </web-app>

下一个ApplicationContext.xml

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">


    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="oracle.jdbc.driver.OracleDriver" />
        <property name="url" value="myurl" />
        <property name="username" value="myacc" />
        <property name="password" value="myacc" />
    </bean>

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="configLocation" value="/WEB-INF/mybatis-config.xml" />
    </bean>
    <bean id="cardValidationService" class="com.programmingfree.springservice.dao.CardValidationService">
        <property name="sqlSessionFactory" ref="sqlSessionFactory" />
    </bean>
</beans>

下一步，mybatis-config.xml

<configuration>
  <typeAliases>

    <typeAlias alias="CardNo" type ="com/programmingfree/springservice/domain/CardNo" />

  </typeAliases>
  <mappers>
    <mapper resource="com/programmingfree/springservice/domain/CardNoMapper.xml"/>
  </mappers>

</configuration>

然后在域名CardNo.java中（删除getter和setter以使帖子更短）

    public String cardNo;
    public String email;
    Date dob;

然后CardNoMapper.xml

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

<mapper namespace="com/programmingfree/springservice/domain/CardNo">

  <resultMap id="cardNoMap" type="CardNo">
  <id property="cardNo" column="CARD_NO" javaType="String" jdbcType="VARCHAR"/>
  <result property="email"  column="EMAIL" javaType="String" jdbcType="VARCHAR"/>
  <result property="dob"  column="DOB" javaType="java.util.Date" jdbcType="DATE"/>
  </resultMap>

  <select id="getCardNoBy" parameterType="map" resultMap="cardNoMap">
  select  * from user where CARD_NO=#{cardNo}
  </select>

</mapper>

在控制器中：

@RestController
@RequestMapping("/service/cardValidate/")
public class CardValidationController {
    @Autowired CardValidationService cardService;

    @RequestMapping(value = "/{cardNumber}", method = RequestMethod.GET, headers = "Accept=application/json")
    public String getCard(@PathVariable String cardNumber) {
        String card = cardService.getCardNoBy(cardNumber);
        return card;
    }
}

最后一个是CardValidationService：

@Service
public class CardValidationService {

    private SqlSessionFactory sqlSessionFactory = null;

    public CardValidationService() {

    }

    public CardValidationService(SqlSessionFactory sqlSessionFactory) {
        this.sqlSessionFactory = sqlSessionFactory;

    }

    public String getCardNoBy(String cardNo) {
        SqlSession session = sqlSessionFactory.openSession();
        System.out.println(cardNo);
        String name = null;

        try {
            name = (String) session
                    .selectOne(
                            "com.programmingfree.springservice.domain.CardNo.getCardNoBy",
                            cardNo);
        } catch (Exception e) {
            System.out.println("Error: " + e.getMessage());
        } finally {
            session.close();
        }
        return name;
    }
}

然后我跑了，我收到了一堆错误：

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:943)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:822)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:807)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

我搜索了这些错误，他们建议在

中添加@Autowired

@Autowired CardValidationService cardService = new CardValidationService（）;

然后得到另一个错误：

javax.servlet.ServletException: Servlet.init() for servlet rest threw exception
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
    org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668)
    org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2463)
    org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2452)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    java.lang.Thread.run(Thread.java:745)

更新2

我不确定是否将xml文件放在正确的文件夹中。 wex.xml, ApplicationContext.xml, mybatis-config.xml, rest-servlet.xml位于同一WEB-INF dir

Answer 1

请试试这个：

a）在控制器类

上

@Autowired
   CardValidationService cardValidationService;

b）在服务类

上

@Service
   public class CardValidationService {

c）对于惯例，请将类CardNo的所有实例变量设为私有。

您获得NullPointerException的原因是您在控制器类中创建了一个简单的CardValidationService Java bean，它没有注入任何依赖项，因为您还没有使用Spring创建的bean。你还没有在你的spring配置中将你的CardValidationService声明为bean，所以即使spring也不会将该类创建为spring-bean。

无法将myBatis集成到现有的Spring Restful Web服务中

1 个答案: