我遵循Spring Mail教程中的Spring Mail文档步骤27.1 - 27.2.2。我的目标是为已经创建的Spring-MVC项目添加电子邮件功能。我在创建一个新的SimpleMailMessage对象时遇到了java.lang.NullPointerException（下面的完整堆栈跟踪中有更多细节）。
我试图尽可能接近教程
public class SimpleOrderManager implements OrderManager {
private MailSender mailSender;
private SimpleMailMessage templateMessage;
public void setMailSender(MailSender mailSender) {
this.mailSender = mailSender;
}
public void setTemplateMessage(SimpleMailMessage templateMessage) {
this.templateMessage = templateMessage;
}
public void placeOrder(User user) {
SimpleMailMessage msg = new SimpleMailMessage(this.templateMessage);
msg.setTo(user.getEmail());
msg.setText("Dear you");
try{
this.mailSender.send(msg);
}
catch (MailException ex) {
System.err.println(ex.getMessage());
}
}
我发现related case仍未解决。
我向Maven添加了Javax Mail依赖项。
另外，我已创建applicationContext-mail.xml配置文件，我确保web.xml文件引用该文件
<?xml version="1.0" encoding="UTF-8"?>
<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.xsd">
<bean id="mailSender" class="org.springframework.mail.javamail.JavaMailSenderImpl">
<property name="host" value="mail.location.company.edu"/>
</bean>
<!-- this is a template message that we can pre-load with default state -->
<bean id="templateMessage" class="org.springframework.mail.SimpleMailMessage">
<property name="from" value="myEmail@mail.org"/>
<property name="subject" value="Your order"/>
</bean>
<bean id="reminderManager" class="edu.company.peerreview.mvc.utility.SimpleOrderManager">
<property name="mailSender" ref="mailSender"/>
<property name="templateMessage" ref="templateMessage"/>
</bean>
</beans>
SEVERE: Servlet.service() for servlet [peerReview] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException
at edu.example.department.peerreview.mvc.utility.SimpleOrderManager.placeOrder(SimpleOrderManager.java:61)
at edu.example.department.peerreview.mvc.HomeController.home(HomeController.java:25)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:212)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:629)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:590)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:900)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:827)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:874)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:779)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
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.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:312)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:116)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:324)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:324)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:101)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:324)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:324)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:324)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:324)
at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:324)
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:182)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:324)
at edu.example.department.peerreview.security.RequestParameterAuthenticationFilter.doFilter(RequestParameterAuthenticationFilter.java:58)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:324)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:324)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:324)
at org.springframework.security.web.session.ConcurrentSessionFilter.doFilter(ConcurrentSessionFilter.java:125)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:324)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:174)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:196)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:722)
错误来自Assert声明
SimpleMailMessage public SimpleMailMessage(SimpleMailMessage original) {
Assert.notNull(original, "The 'original' message argument cannot be null");
this.from = original.getFrom();
this.replyTo = original.getReplyTo();
if (original.getTo() != null) {
this.to = copy(original.getTo());
}
if (original.getCc() != null) {
this.cc = copy(original.getCc());
}
if (original.getBcc() != null) {
this.bcc = copy(original.getBcc());
}
this.sentDate = original.getSentDate();
this.subject = original.getSubject();
this.text = original.getText();
}
据我所知，我已经完成了教程中的所有说明。在simpleOrderManager中，我尝试在创建新实例时使用空构造函数SimpleMailMessage msg = new SimpleMailMessage() but that gives me a null pointer expection error when executing this.mailSender.send（msg）;`
@RequestMapping(value = "/", method = RequestMethod.GET)
public String home(Model model) {
// Redirect to the user's dashboard
SimpleOrderManager qaFollowUp = new SimpleOrderManager();
User user = userDAO.findById(485);
qaFollowUp.placeOrder(user);
return "redirect:/users/" + getAuthenticatedUser().getId() + "/dashboard/" + UserHelper.getURLName(getAuthenticatedUser());
}
答案 0 :(得分：1)
你必须让Spring注入 SimpleOrderManager bean。如果你用 new 创建它，Spring就不会意识到它（它不是应用程序上下文的一部分）并且不会自动装配它的依赖项（在你的情况下> templateMessage 。