如果我使用“实现",则Spring Injection无法正常工作在班上 [英] Spring Injection not working if i use "implements" in class
问题描述
这是我以前的问题 Spring Injection在不同的服务类中不起作用
@Service("securityService")
@Transactional
public class SecurityService implements UserDetailsService {
protected static Logger logger = Logger.getLogger("service");
@Autowired
public RegistrationDAO registrationDAO;
public String test(){
logger.debug(registrationDAO.findUserByID(1) );
return "test";
}
在上面的代码中,没有正确注入registrationDAO并给出了空指针异常,但是现在我发现,如果我从类中删除了工具,则其工作方式如下
In above code registrationDAO is not properly injected and give null pointer exception but Now i have found that if i remove implements from class then it works like below
@Service("securityService")
@Transactional
public class SecurityService {
protected static Logger logger = Logger.getLogger("service");
@Autowired
public RegistrationDAO registrationDAO;
public String test(){
logger.debug(registrationDAO.findUserByID(1) );
return "manta";
}
我需要使用该接口来使用spring安全认证,所以我应该怎么做
I need to use that interface to use spring security authentication , so what should i do
堆栈跟踪
enter code here
java.lang.NullPointerException
com.vaannila.dao.RegistrationDAOimpl.findUserByID(RegistrationDAOimpl.java:63)
com.vaannila.service.SecurityService.loadUserByUsername(SecurityService.java:68)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
xml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"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">
<!-- Activates various annotations to be detected in bean classes -->
<!-- Scans the classpath for annotated components that will be auto-registered as Spring beans.
For example @Controller and @Service. Make sure to set the correct base-package-->
<bean id="userService" class="com.vaannila.service.UserServiceImpl" />
<bean id="userValidator" class="com.vaannila.validator.UserValidator" />
<bean id="userDAO" class="com.vaannila.dao.UserDAO" />
<bean id="registrationDAO" class="com.vaannila.dao.RegistrationDAO" />
<!-- Configures the annotation-driven Spring MVC Controller programming model.
Note that, with Spring 3.0, this tag works in Servlet MVC only! -->
</beans>
推荐答案
我对Spring也比较陌生,但是当我遇到此问题并且它不起作用时,我在自动装配后添加了set方法,例如这个:
I'm relatively new to Spring as well, but when I had this problem and it didn't work, I added a set method after the autowired, like this:
@Autowired
public RegistrationDAO registrationDAO;
public void setRegistrationDAO(RegistrationDAO registrationDAO) {
this.registrationDAO = registrationDAO;
}
这就是对我有用的方法,我将它用于同一件事,即在您的servlet容器xml文件中声明的DAO.在某些情况下,我在没有二传手的情况下尝试了该方法,但该方法不起作用.
That's what worked for me, and I use it for the same thing, the DAOs that are declared in your servlet container xml file. In some cases I tried it without the setter and it did not work.
祝你好运!
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