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我使用Velocity和Java郵件發件人，但我得到一個NullPointerException，我不知道爲什麼。我嘗試了很多，但無法解決問題，說實話，我不知道問題依賴於什麼。速度電子郵件不工作
以下是我使用的示例代碼。 感謝您的幫助。
SEVERE: Servlet.service() for servlet [mvc-dispatcher] in context with path [/guard_weblayer] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException
at se.guards.mail.VelocityEmailService.sendLostPasswordEmail(VelocityEmailService.java:49)
at se.guards.lostpassword.LostPasswordController.processSubmit(LostPasswordController.java:71)
public interface VelocityMailRepository
{
public void sendLostPasswordEmail(final User user, final String action);
}
public class VelocityEmailService implements VelocityMailRepository
{
private static final Logger logger= LoggerFactory.getLogger(VelocityEmailService.class);
@Autowired
private VelocityEngine velocity;
@Autowired
private JavaMailSenderImpl javaMailSenderImpl;
@Autowired
private JavaMailSender sender;
public void sendLostPasswordEmail(final User user, final String action)
{
logger.debug("Sending lost password email to: {}", user.getUsername());
MimeMessagePreparator preparator = new MimeMessagePreparator() {
public void prepare(MimeMessage mimeMessage) throws Exception {
MimeMessageHelper message = new MimeMessageHelper(mimeMessage);
message.setTo(user.getEmail());
message.setFrom("[email protected]");
message.setSubject("Your Password");
Map<String, Object> model = new HashMap<String, Object>();
model.put("user", user);
model.put("url", action);
String text = mergeTemplateIntoString(velocity, "email/lost-password.vm","password", model);
message.setText(text, true);
}
};
this.sender.send(preparator);
}
public class LostPasswordFormValidator implements Validator {
private static final Logger logger = LoggerFactory.getLogger(LostPasswordFormValidator.class);
public boolean supports(Class clazz) {
return LostPasswordForm.class.equals(clazz);
}
public void validate(Object obj, Errors errors) {
logger.debug("Validating lost password form.");
LostPasswordForm form = (LostPasswordForm) obj;
// Insure that a value with specified.
rejectIfEmptyOrWhitespace(errors, "username", "error.username.empty");
// Insure the inputs don't contain any illegal characters.
if (!isAlphanumeric(form.getUsername()))
errors.rejectValue("username", "error.username.illegal.chars");
if (isNotBlank(form.getUsername()) && form.getUsername().length() < 4)
errors.rejectValue("username", "error.username.too.short");
}
}
@Controller
public class LostPasswordController
{
private static final Logger logger = LoggerFactory.getLogger(LostPasswordController.class);
VelocityEmailService sender= new VelocityEmailService();
UserService service= new UserService();
@InitBinder
public void initBinder(WebDataBinder binder)
{
binder.setAllowedFields(new String[] { "captcha", "username" });
}
@ModelAttribute("form")
public LostPasswordForm populateForm()
{
return new LostPasswordForm();
}
@RequestMapping(value = "/lostPassword", method = RequestMethod.GET)
public String lostPassword()
{
logger.debug("Rendering lost password form.");
return "lostPassword";
}
@RequestMapping(value = "/lostPassword", method = RequestMethod.POST)
public String processSubmit(@ModelAttribute("form") LostPasswordForm form,HttpServletResponse response, BindingResult result)
{
logger.debug("Processing lost password form.");
new LostPasswordFormValidator().validate(form, result);
if (!result.hasErrors())
{
User user = service.findUserByUsername(form.getUsername());
System.out.println(user);
if (user != null)
{
String frob = BCrypt.hashpw(user.getUsername() + "3m4il", BCrypt.gensalt());
String link = createLostPasswordLink(user, frob);
sender.sendLostPasswordEmail(user, link);
response.addCookie(persistFrob(frob));
return "lost-password-success";
}
result.rejectValue("username", "error.username.invalid");
}
return "lostPassword";
}
private String createLostPasswordLink(final User user, final String frob)
{
StringBuilder link = new StringBuilder();
link.append("http://localhost:8080/password/reset.do?frob=");
link.append(frob);
link.append("&username=");
link.append(user.getUsername());
return link.toString();
}
private Cookie persistFrob(final String frob)
{
Cookie cookie = new Cookie("frob", frob);
cookie.setMaxAge(60 * 60); // 1 hour
return cookie;
}
}
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:p="http://www.springframework.org/schema/p"
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-3.1.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.1.xsd">
<context:component-scan base-package=".........weblayer" />
<mvc:annotation-driven />
<context:annotation-config />
<mvc:resources mapping="/resources/**" location="/resources/" />
<context:property-placeholder location="classpath*:*.properties" />
<bean id="messageTemplate" class="org.springframework.mail.SimpleMailMessage"
scope="prototype">
<property name="from" value="myemailaddress" />
</bean>
<!-- - This bean resolves specific types of exceptions to corresponding
logical - view names for error views. The default behaviour of DispatcherServlet
- is to propagate all exceptions to the servlet container: this will happen
- here with all other types of exceptions. -->
<bean
class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
<property name="exceptionMappings">
<props>
<prop key="org.springframework.web.servlet.PageNotFound">pageNotFound</prop>
<prop key="org.springframework.dao.DataAccessException">dataAccessFailure</prop>
<prop key="org.springframework.transaction.TransactionException">dataAccessFailure</prop>
</props>
</property>
</bean>
<bean
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/views/users/" />
<property name="suffix" value=".jsp" />
</bean>
<bean id="messageSource"
class="org.springframework.context.support.ResourceBundleMessageSource">
<property name="basenames" value="mymessages"></property>
</bean>
<bean id="multipartResolver"
class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<!-- max upload size in bytes -->
<property name="maxUploadSize" value="50242880" />
<!-- max size of file in memory (in bytes) -->
<property name="maxInMemorySize" value="1048576" /> <!-- 1MB -->
</bean>
<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />
<bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" />
</beans>
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.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">
<bean id="mailSender" class="org.springframework.mail.javamail.JavaMailSenderImpl">
<property name="host" value="${mail.host}" />
<property name="username" value="${mail.username}" />
<property name="password" value="${mail.password}" />
<property name="port" value="${mail.port}" />
<property name="protocol" value="smtp" />
<property name="javaMailProperties">
<props>
<prop key="mail.smtp.auth">${mail.smtp.auth}</prop>
<prop key="mail.smtp.connectiontimeout">5000</prop>
<prop key="mail.smtp.sendpartial">${mail.smtp.sendpartial}</prop>
<prop key="mail.smtp.userset">${mail.smtp.userset}</prop>
<prop key="mail.mime.charset">UTF-8</prop>
<prop key="mail.smtp.isSecure">${mail.smtp.isSecure}</prop>
<prop key="mail.smtp.requiresAuthentication">${mail.smtp.requiresAuthentication}</prop>
<prop key="mail.smtps.auth">${mail.smtps.auth}</prop>
<prop key="mail.smtp.port">${mail.port}</prop>
<prop key="mail.smtp.socketFactory.class">javax.net.ssl.SSLSocketFactory</prop>
<prop key="mail.smtp.socketFactory.fallback">${mail.smtp.socketFactory.fallback}</prop>
<prop key="mail.smtp.starttls.enable">${mail.smtp.starttls.enable}</prop>
<prop key="mail.debug">${mail.debug}</prop>
</props>
</property>
</bean>
<bean id="messageTemplate" class="org.springframework.mail.SimpleMailMessage"
scope="prototype">
<property name="from" value="${mail.username}" />
</bean>
<!-- Mail sender configured for using Gmail -->
<bean id="mailSender" class="org.springframework.mail.javamail.JavaMailSenderImpl"
p:host="smtp.gmail.com" p:username="${mail.username}" p:password="${mail.password}">
<property name="javaMailProperties">
<props>
<prop key="mail.smtp.auth">true</prop>
<prop key="mail.smtp.starttls.enable">true</prop>
</props>
</property>
</bean>
<bean id="velocityEngine"
class="org.springframework.ui.velocity.VelocityEngineFactoryBean">
<property name="velocityProperties">
<props>
<prop key="resource.loader">class</prop>
<prop key="class.resource.loader.class">org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader
</prop>
</props>
</property>
</bean>
</beans>
解決 只是改變 VelocityEmailService發件人=新VelocityEmailService（）; UserService service = new UserService（）; 至 VelocityEmailService sender; UserService服務; 不需要啓動 – user1067665