SPRING MVC3.2案例讲解--异常处理

SPRING MVC 异常处理 可以全局进行定义，也可以单独在SPRING controller中定义；同时SPRING MVC将异常处理的代码和业务逻辑进行分离，将异常的处理放到一个单独的带有@ExceptionHandler方法中；

@Controller
public class ExceptionController {

      
	@RequestMapping("/exception")
	public @ResponseBody String exception() {
		throw new IllegalStateException("Sorry!");
	}

       // 处理异常的代码，这样就实现了业务逻辑和异常处理的分离
	@ExceptionHandler
	public @ResponseBody String handle(IllegalStateException e) {
		return "IllegalStateException handled!";
	}

	@RequestMapping("/global-exception")
	public @ResponseBody String businessException() throws BusinessException {
		throw new BusinessException();
	}

}

SPRING 处理异常的流程：

1.WEB启动时ExceptionHandlerExceptionResolver 扫描到通用的异常处理方法：

DEBUG ExceptionHandlerExceptionResolver Looking for exception mappings: WebApplicationContext for namespace 'appServlet-servlet': startup date [Sat Jun 08 08:40:41 GMT 2013]; parent: Root WebApplicationContext

INFO  ExceptionHandlerExceptionResolver Detected @ExceptionHandler methods in globalExceptionHandler

2.当请求出现异常时，首先看当前类中是否含有@ExceptionHandler的处理方法

DEBUG ExceptionHandlerExceptionResolver Resolving exception from handler [public java.lang.String org.springframework.samples.mvc.exceptions.ExceptionController.exception()]: java.lang.IllegalStateException: Sorry!

DEBUG ExceptionHandlerExceptionResolver Invoking @ExceptionHandler method: public java.lang.String org.springframework.samples.mvc.exceptions.ExceptionController.handle(java.lang.IllegalStateException)

DEBUG RequestResponseBodyMethodProcessor Written [IllegalStateException handled!] as "text/plain;charset=ISO-8859-1" using [org.springframework.http.converter.StringHttpMessageConverter@163e9a1]

3.然后看有没有含有@ExceptionHandler method 的类，另外该类必须@ControllerAdvice

DEBUG ExceptionHandlerExceptionResolver Resolving exception from handler [public java.lang.String org.springframework.samples.mvc.exceptions.ExceptionController.businessException() throws org.springframework.samples.mvc.exceptions.BusinessException]: org.springframework.samples.mvc.exceptions.BusinessException

DEBUG ExceptionHandlerExceptionResolver Invoking @ExceptionHandler method: public java.lang.String org.springframework.samples.mvc.exceptions.GlobalExceptionHandler.handleBusinessException(org.springframework.samples.mvc.exceptions.BusinessException)