在项目中，我们不可否认的会出现异常，而且这些异常并没有进行捕获。经常出现的bug如空指针异常等等。
基于注解的异常映射
一、
①在自动扫描的包的范围内声明一个类，此类用@ControllerAdvice注解标记 ，在该类中声明一个标记了@ExceptionHandler注解的方法
@ControllerAdvice
public class GlobalExceptionMapping {
@ExceptionHandler(value=Exception.class)
public ModelAndView globalExceptionMapping(Exception exception) {
ModelAndView modelAndView = new ModelAndView("global-error");
modelAndView.addObject("globalException", exception);
return modelAndView;
}
}
②错误页面
<body>
<h1>Global Error</h1>
指定属性名的错误消息：${requestScope.globalException }<br/>
</body>
二、
①新建GlobalExceptionResover实现HandlerExceptionResolver
/**
* 全局异常捕获
* @author XXX
*
*/
public class GlobalExceptionResolver implements HandlerExceptionResolver{
@Override
public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler,
Exception exception) {
//--------------------------------------------
return null;
}
}
public class ExceptionResolver implements HandlerExceptionResolver {
private Log LOG = LogFactory.getLog(ExceptionResolver.class);
@Autowired
private ObjectMapperProvider objectMapperProvider;
@ResponseBody
@Override
public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler,Exception ex) {
String result = "";
BaseResponse respModel = new BaseResponse();
try {
if (ex instanceof ResponseErrorException) {
respModel.setReturn_code(((ResponseErrorException) ex).getCode());
respModel.setReturn_message(ex.getMessage());
} else {
LOG.error("#请求处理异常：", ex);
if (ex instanceof com.fasterxml.jackson.databind.JsonMappingException) {
respModel.setReturn_code("-1");
respModel.setReturn_message("JSON转换异常！");
} else if (ex instanceof com.alibaba.dubbo.remoting.TimeoutException) {
respModel.setReturn_code("-1");
respModel.setReturn_message("调用后台服务时超时！");
} else {
respModel.setStatus("FAIL");
respModel.setReturn_code("-1");
respModel.setReturn_message("请求处理异常：".concat(ExceptionUtils.getMessage(ex)));
}
respModel.setReturn_code(SystemReturnCodeEnum.SYSTEM_ERROR.getCode());
respModel.setReturn_message("请求处理异常：".concat(ExceptionHelper.getExceptionMessage(ex)));
}
result = objectMapperProvider.getObjectMapper().writeValueAsString(respModel);
response.setCharacterEncoding("UTF-8");
response.setContentType("text/json;charset=UTF-8");
response.getWriter().write(result);
response.setStatus(HttpStatus.SC_OK);//200
} catch (Exception e) {
LOG.error("全局异常!", e);
}
ModelAndView mav = new ModelAndView();
return mav;
}
②在Spring配置文件中配置刚才新建的类
<!--全局异常捕捉 --> <bean class="com.ssm.exception.GlobalExceptionResolver" />
基于XML的异常映射
①配置SimpleMappingExceptionResolver,在excceptionMappings属性中指定映射关系
<bean id="simpleMappingExceptionResolver" class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
<property name="exceptionMappings">
<props>
<prop key="java.lang.BizException">global-error</prop> global-error 视图名称会去拼前后缀
<prop key="java.lang.LogInException">logIn-error</prop> logIn-error 视图名称会去拼前后缀
</props>
</property>
</bean>
②错误页面
<body>
<h1>Global Error</h1>
系统默认的异常对象属性名：${requestScope.exception }
</body>
一般异常映射用XML即可，便于统一的管理，基于注解的全局映射好处：可以写java代码，可以将异常信息保存到文件或数据库中