Question

我正在尝试使用spring做电子邮件功能（出于我的学习目的）。以下是代码段：

@Autowired
static
ApplicationContext applicationContext;
/**
 * <p>
 * Utility classes, which are collections of static members, are not meant to be
 * instantiated. Even abstract utility classes, which can be extended, should
 * not have public constructors.
 * 
 * Java adds an implicit public constructor to every class which does not define
 * at least one explicitly. Hence, at least one non-public constructor should be
 * defined.
 * 
 * </p>
 */
private EmailUtility() {
}

//@Autowired
//private static JavaMailSender mailSender;

public static void sendSimpleMessage(String to, String subject, String text, boolean trainTicket,
        boolean flightTicket) throws MessagingException {



    JavaMailSender mailSender = applicationContext.getBean("mailSender",JavaMailSenderImpl.class);
    MimeMessage message = mailSender.createMimeMessage();
    String pathToAttachment = "";
    MimeMessageHelper helper = new MimeMessageHelper(message, true);

    helper.setTo(to);
    helper.setSubject(subject);
    helper.setText(text);

    if (trainTicket && !flightTicket) {
        pathToAttachment = AppConstants.TRAIN_TICKET_FILE;
    } else if (!trainTicket && flightTicket) {
        pathToAttachment = AppConstants.FLIGHT_TICKET_FILE;
    }

    if (Objects.nonNull(pathToAttachment) && !pathToAttachment.isEmpty()) {
        FileSystemResource file = new FileSystemResource(new File(pathToAttachment));
        helper.addAttachment("Ticket", file);
    }

    mailSender.send(message);
}

}

我的应用程序上下文：

<!-- Step 3: Add support for component scanning -->
<context:component-scan base-package="com.patcyy.vamonos" />

<!-- Step 4: Add support for conversion, formatting and validation support -->
<mvc:annotation-driven/>

 <bean id="mailSender" class="org.springframework.mail.javamail.JavaMailSenderImpl">
    <property name="host" value="abcd.abcd.com"/>
    <property name="port" value="2525"/>
    <property name="username" value="admin@abcd.com"/>
    <property name="password" value="test"/>
    <property name="javaMailProperties">
        <props>
            <prop key="mail.transport.protocol">smtp</prop>
            <prop key="mail.smtp.auth">true</prop>
            <prop key="mail.smtp.starttls.enable">true</prop>
            <prop key="mail.debug">true</prop>
        </props>
    </property>
</bean>

在初始化JavaMailSender时，我得到了nullpointer异常。（在这一行中，JavaMailSender mailSender = applicationContext.getBean（“ mailSender”，JavaMailSenderImpl.class）;）

StackTrace：

java.lang.NullPointerException 在com.patcyy.vamonos.utills.EmailUtility.sendSimpleMessage（EmailUtility.java:61）在com.patcyy.vamonos.services.StaticContentService.postEnquiry（StaticContentService.java:82）在com.patcyy.vamonos.controller.StaticContentController.postEnquiry（StaticContentController.java:143）在sun.reflect.NativeMethodAccessorImpl.invoke0（本机方法）处在sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:62）在sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）在java.lang.reflect.Method.invoke（Method.java:498）在org.springframework.web.method.support.InvocableHandlerMethod.doInvoke（InvocableHandlerMethod.java:209）在org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest（InvocableHandlerMethod.java:136）在org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle（ServletInvocableHandlerMethod.java:102）在org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod（RequestMappingHandlerAdapter.java:891）在org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal（RequestMappingHandlerAdapter.java:797）在org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle（AbstractHandlerMethodAdapter.java:87）在org.springframework.web.servlet.DispatcherServlet.doDispatch（DispatcherServlet.java:991）在org.springframework.web.servlet.DispatcherServlet.doService（DispatcherServlet.java:925）在org.springframework.web.servlet.FrameworkServlet.processRequest（FrameworkServlet.java:974）在org.springframework.web.servlet.FrameworkServlet.doPost（FrameworkServlet.java:877）在javax.servlet.http.HttpServlet.service（HttpServlet.java:660）在org.springframework.web.servlet.FrameworkServlet.service（FrameworkServlet.java:851）在javax.servlet.http.HttpServlet.service（HttpServlet.java:741）在org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:231）在org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:166）在org.apache.tomcat.websocket.server.WsFilter.doFilter（WsFilter.java:53）在org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:193）在org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:166）在org.apache.catalina.core.StandardWrapperValve.invoke（StandardWrapperValve.java:199）在org.apache.catalina.core.StandardContextValve.invoke（StandardContextValve.java:96）在org.apache.catalina.authenticator.AuthenticatorBase.invoke（AuthenticatorBase.java:490）在org.apache.catalina.core.StandardHostValve.invoke（StandardHostValve.java:139）在org.apache.catalina.valves.ErrorReportValve.invoke（ErrorReportValve.java:92）在org.apache.catalina.valves.AbstractAccessLogValve.invoke（AbstractAccessLogValve.java:668）在org.apache.catalina.core.StandardEngineValve.invoke（StandardEngineValve.java:74）在org.apache.catalina.connector.CoyoteAdapter.service（CoyoteAdapter.java:343）在org.apache.coyote.http11.Http11Processor.service（Http11Processor.java:408）在org.apache.coyote.AbstractProcessorLight.process（AbstractProcessorLight.java:66）在org.apache.coyote.AbstractProtocol $ ConnectionHandler.process（AbstractProtocol.java:770）在org.apache.tomcat.util.net.NioEndpoint $ SocketProcessor.doRun（NioEndpoint.java:1415）在org.apache.tomcat.util.net.SocketProcessorBase.run（SocketProcessorBase.java:49）在java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1149）在java.util.concurrent.ThreadPoolExecutor $ Worker.run（ThreadPoolExecutor.java:624）在org.apache.tomcat.util.threads.TaskThread $ WrappingRunnable.run（TaskThread.java:61）在java.lang.Thread.run（Thread.java:748）

Answer 1

我认为主要的问题是您将实用程序定义为服务。无论如何，如果您想在非托管对象中使用Spring托管bean，可以执行以下操作

@Component public class ContextInitializer {

@Autowired
private JavaMailSender mailSender;

@PostConstruct
public void postConstruct() {
    EmailUtility.setMailSender(mailSender);
}

}

并在EmailUtility类中添加一个setter方法。

使用Spring Mail发送电子邮件时获取空指针异常

1 个答案: