用sbt编译spring的问题

最近在用sbt开发springmvc应用，其实主要是为了能用scala，因为对spring还不是很熟，资料里都是用Java写的，所以暂时倒还没有用scala写。今天配置aop，大概代码如下：

@Around(value = "execution(* get(..)) && args(bookId, session) && @annotation(m)")
	public Object doGetBook(ProceedingJoinPoint pjp, long bookId, HttpSession session, MonitorPerformance m)
			throws Throwable {}

@RequestMapping(value = "/1", method = RequestMethod.GET)
	@ResponseBody
	@MonitorPerformance(2)
	public String get(@RequestParam(value = "bookId", required = false) long bookId, HttpSession session) {}

不过container:restart的时候总是报异常：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'config': BeanPostProcessor before instantiation of bean failed; nested exception is org.springframework.aop.aspectj.AspectJAdviceParameterNameDiscoverer$AmbiguousBindingException: Found 2 candidate variable names but only one candidate binding slot when matching primitive args
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:471)
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:700)
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:760)

以为是不能用long，于是改为Long，还有异常如下：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'config': BeanPostProcessor before instantiation of bean failed; nested exception is org.springframework.aop.aspectj.AspectJAdviceParameterNameDiscoverer$AmbiguousBindingException: Still 2 unbound args at this(),target(),args() binding stage, with no way to determine between them
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:471)
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:700)

但是发现，这次在eclipse里面是可以单独跑起来的，但是用sbt编译过后就是不行！后来想到是不是因为sbt编译没有保留debug信息的缘故，因为eclipse默认是保留的，于是把eclipse的去掉，果然不行！然后在sbt里面加上保留debug信息的配置：

javacOptions ++= Seq("-g")

但是其实不是在任何环境下都可以保留debug信息的，难道spring没有提供这种场景下的使用机会？！肯定不对！google之后发现，原来是可以@Around(@Before, @After等也可以)中配置argNames的。如下：

@Around(value = "execution(* get(..)) && args(bookId, session) && @annotation(m)", argNames="pjp, bookId, session, m")
	public Object doGetBook(ProceedingJoinPoint pjp, Long bookId, HttpSession session, MonitorPerformance m)
			throws Throwable {}

这样就可以把sbt里javaOptions去掉！然后访问的时候又异常！

nested exception is java.lang.IllegalStateException: No parameter name specified for argument of type [java.lang.Long], and no parameter name information found in class file either

有了刚刚的经验，很容易知道，应该还是没有debug信息的问题。spring需要指定@RequestParam，可以这样配置：

@RequestMapping(value = "/1", method = RequestMethod.GET)
	@ResponseBody
	@MonitorPerformance(2)
	public String get(@RequestParam(value = "bookId", required = false) Long bookId, HttpSession session) {}

required默认为true，不修改的话，不带参数会报错的，为了测试简单我修改为false。

总结就是配置的时候尽量全面，不要依赖编译时候会有debug信息。因为method的参数，如果没有保留debug信息，是不知道名字的。对于class类型的话，到可以通过Class信息判断，但是对于primitive以及对于的wrapper类，还有String，都是不行的。