这篇文章主要讲解了Spring boot如何集中异常处理,内容清晰明了,对此有兴趣的小伙伴可以学习一下,相信大家阅读完之后会有帮助。
方式一:ExceptionHandle
定义自己的异常类型,根据不同类型做不同处理,比如我定义的MyException:
public class MyException extends RuntimeException { public MyException(String msg) { super(msg); } }
然后通过MyExceptionHandle处理该异常,需要注意的是异常不能在filter中抛出,抛出也没法捕获
@RestControllerAdvice public class MyExceptionHandle { @ExceptionHandler(MyException.class) public Result exceptionHandle(MyException e) { return Result.getFailed( "system error:MyException" + e.getMessage()); } }
在controller、service以及拦截器的预处理方法中都可以完美捕获,这里特殊说下拦截器:
public class MyInterceptor implements HandlerInterceptor { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) { //throw new MyException("拦截器错误:MyInterceptor"); // 这里的异常会完美捕获,并返回 return true; } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) { throw new MyException("拦截器错误:MyInterceptor"); /** 能捕获异常信息并返回给客户端,但并不会覆盖已经请求成功的返回结果,但会包含在返回结果中,比如我的返回结果: {"code":1,"success":true,"msg":"请求成功","result":true}{"code":0,"success":false,"msg":"system error:MyException拦截器错误:MyInterceptor","result":null} */ } @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) { throw new MyException("拦截器错误:MyInterceptor"); // 这里抛出的异常并不能被捕获,会直接在后台抛出,相当于回掉函数,请求结果已经返回 } }
上面的解释已经够清楚了,就不做过多说明了。刚刚我们说了,上面的这种方式,对于filter是不起作用的,下面我们说的这种方式,主要就是针对filter来说的
方式二:ExceptionFilter
定义一个controller,请求路径可以自己指定,比如/error/exthrow:
@Controller public class ExceptionController { @RequestMapping("/error/exthrow") public void rethrow(HttpServletRequest request) throws Exception { throw ((Exception) request.getAttribute("filter.error")); } }
再定义一个异常拦截器,在需要抛出异常的拦截器中直接抛出异常,然后在异常拦截器中try-catch,发生异常时直接转发至前面定义的异常controller,这里需要注意的是,如果你的filter是实现Filter或者继承OncePerRequestFilter,那你不需要任何处理,直接request.setAttribute("filter.error", e)就可以了。
由于我把自己的filter交给shiro管理,而且是继承BasicHttpAuthenticationFilter的,不知到什么原因,直接catch到的异常类型是ServletException,为了拿到真正的异常信息,我需要通过getCause()方法获取filter中抛出的异常。因为controller抛出的异常最后还是会交给我们定义的MyExceptionHandle去处理,如果获取到的异常不是我们自定义的异常或者他的子类的话,就会返回500错误(在这个示例前,我以为所有的filter都是这样的,后来实践后发现并不是这样😂)。
@Component public class ExceptionFilter implements Filter { @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { try { chain.doFilter(request, response); } catch (Exception e) { request.setAttribute("filter.error", e); //将异常分发到/error/exthrow控制器 request.getRequestDispatcher("/error/exthrow").forward(request, response); } } @Override public void init(FilterConfig filterConfig) throws ServletException { } @Override public void destroy() { } }
我的filter:
实现Filter接口:
public class MyFilter implements Filter { @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { throw new MyException("MyFilter过滤器抛出异常"); //filterChain.doFilter(servletRequest, servletResponse); } }
filter2继承OncePerRequestFilter:
public class MyFilter2 extends OncePerRequestFilter { @Override protected void doFilterInternal(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, FilterChain filterChain) throws ServletException, IOException { throw new MyException("MyFilter2异常"); } }
filter配置类:
@Bean public FilterRegistrationBean myFilterRegistration() { FilterRegistrationBean registration = new FilterRegistrationBean(); registration.setFilter(new MyFilter()); registration.setName("myFilter"); registration.addUrlPatterns("/*"); //此处尽量小,要比其他Filter靠前 registration.setOrder(1); return registration; } @Bean public FilterRegistrationBean myFilter2Registration() { FilterRegistrationBean registration = new FilterRegistrationBean(); registration.setFilter(new MyFilter2()); registration.setName("myFilter2"); registration.addUrlPatterns("/*"); //此处尽量小,要比其他Filter靠前 registration.setOrder(2); return registration; } /** * 配置拦截器 * @return */ @Bean public FilterRegistrationBean exceptionFilterRegistration() { FilterRegistrationBean registration = new FilterRegistrationBean(); registration.setFilter(new ExceptionFilter()); registration.setName("exceptionFilter"); //此处尽量小,要比其他Filter靠前 registration.setOrder(-1); return registration; }
方式三:BasicErrorController
其实spring boot原生提供了异常集中处理,我们经常会看到:
但是这种方式不够友好,而且大部分情况不满足我们的需求,我们可以通过继承这个controller,然后重写error方法或者errorHtml方法,或者两个都重写,区别是errorHtml是处理请求头为text/html的请求发生的异常,而error是除了这个之外的其他异常。
下面是我定义的baseController,error部分返回的结果是空,还需要进一步的研究:
@RestController @RequestMapping(value = "error") public class MyBaseErrorController extends BasicErrorController { public MyBaseErrorController(ErrorAttributes errorAttributes) { super(errorAttributes, new ErrorProperties()); } @Override @RequestMapping(produces = {MediaType.ALL_VALUE}) public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) { return new ResponseEntity<Map<String, Object>>(Result.failedResultMap(000, "未知错误"), HttpStatus.OK); } @RequestMapping( produces = {"text/html"} ) public ModelAndView errorHtml(HttpServletRequest request, HttpServletResponse response) { HttpStatus status = this.getStatus(request); response.setStatus(status.value()); return null; } }
最后,对于以上问题我最后的解决方法是继承ErrorController,然后定义errorHtml和error,更重要的是@RequestMapping注解,然后在方法中response写入返回值,这种方式不够优雅:
@RestController @RequestMapping(value = "error") public class MyBaseErrorController implements ErrorController { private static final String path_default = "/error"; @Autowired private ErrorAttributes errorAttributes; @RequestMapping(produces = {MediaType.ALL_VALUE}) public void error(HttpServletRequest request, HttpServletResponse response) { setJsonError(response); } @RequestMapping( produces = {"text/html"} ) public void errorHtml(HttpServletRequest request, HttpServletResponse response) { setJsonError(response); } @Override public String getErrorPath() { return path_default; } private void setJsonError(HttpServletResponse response) { PrintWriter writer = null; try { response.setStatus(200); response.setHeader("Content-type", "text/html;charset=UTF-8"); response.setCharacterEncoding("UTF-8"); writer = response.getWriter(); writer.write(JSON.toJSONString(Result.getFailed("未知错误", null))); } catch (IOException e) { e.printStackTrace(); } finally { if (writer != null) { writer.close(); } } } }
看完上述内容,是不是对Spring boot如何集中异常处理有进一步的了解,如果还想学习更多内容,欢迎关注亿速云行业资讯频道。
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