小编use*_*841的帖子

我正在写一个春季邮件程序:

@Service("LeaveEmail")
public class LeaveEmail {
    @Autowired
    private MailSender mailSender;

    @Autowired
    private SimpleMailMessage alertMailMessage;
    public void setMailSender(MailSender mailSender) {  
        this.mailSender = mailSender;  
    }       
    public boolean sendMail(LeaveApplyForm leaveApplyForm)
    {
        SimpleMailMessage message = new SimpleMailMessage();

        EmpRegistrationForm empRegistrationForm=new EmpRegistrationForm();
        String to=leaveApplyForm.getFirstApprover();

    //  String to1=leaveApplyForm.getFinalApprover();
        String text=leaveApplyForm.getReason();         
        String from=empRegistrationForm.getEmail();
        String subject="Application for the Leave";

        message.setFrom(from);          
                message.setTo(to);          
                message.setSubject(subject);            
                message.setText(text);          
                mailSender.send(message);           

    return true;    

    }
}

我的spring-servlet.xml是:

<bean id="localeChangeInterceptor"
    class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor">
    <property name="paramName" value="lang" />
</bean>

<bean id="localeResolver"
    class="org.springframework.web.servlet.i18n.CookieLocaleResolver">
    <property name="defaultLocale" value="en"/>
</bean>

    <bean id="handlerMapping"
          class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping">
        <property name="interceptors"> …

我想将字符串转换为Double,如:

Double no_of_leaves_form=Double.parseDouble(leaveapplyform.getNo_of_leaves());

数据库中NO_of_leaves的数据类型为varchar.但我收到以下错误:

 java.lang.NullPointerException
    at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:991)
    at java.lang.Double.parseDouble(Double.java:510)
    at com.dz.hrportal.worker.EmpLeaveApplyWorker.validateUser(EmpLeaveApplyWorker.java:42)
    at com.dz.hrportal.controller.EmpLeaveApplyController.processForm(EmpLeaveApplyController.java:63)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)

有没有人知道如何解决它.