自定义异常

public class UserNotExistException extends RuntimeException { public UserNotExistException(){ super("用户不存在"); } }

5xx.html 页面输出异常信息

<main role="main" class="col-md-9 ml-sm-auto col-lg-10 pt-3 px-4"> <h1>5xx-----status:[[${status}]]</h1> <h2>5xx-----timestamp:[[${timestamp}]]</h2> <h2>5xx-&#45;&#45;&#45;&#45;exception:[[${exception}]]</h2> <h2>5xx-&#45;&#45;&#45;&#45;exception.message:[[${exception.message}]]</h2> </main>

处理请求产生异常

@ResponseBody @RequestMapping("/hello") public String hello(@RequestParam("user") String user){ if("a".equals(user)){ System.out.println("we should throw new UserNotExistException()"); throw new UserNotExistException(); } return "helloworld"; }

输出结果

页面收到的expcetion为null，没有接受到exception

解决5xx.html页面未收到异常：

更改SpringBoot默认配置

默认配置

/** * When to include the "trace" attribute. */ private IncludeStacktrace includeStacktrace = IncludeStacktrace.NEVER; /** * When to include "message" attribute. */ private IncludeAttribute includeMessage = IncludeAttribute.NEVER;

在全局配置文件 application.properties 覆盖默认配置

server.error.include-exception=true server.error.include-message=always

5xx.html成功收获异常

自定义异常处理器

@ControllerAdvice public class MyExceptionHandler { @ResponseBody @ExceptionHandler(UserNotExistException.class) public Map<String,Object> handleException(Exception e){ Map<String,Object> map = new HashMap<>(); //存放自己的错误代码 map.put("code","user.notexist"); map.put("message",e.getMessage()); return map; } }

PostMan测试异常处理器

浏览器页面异常效果

异常显示如何自适应

当前无论浏览器还是非浏览器，返回的都是Json数据，没有达到自适应效果

使用转发能否达到自适应

//@ResponseBody @ExceptionHandler(UserNotExistException.class) public String handleException(Exception e){ Map<String,Object> map = new HashMap<>(); //存放自己的错误代码 map.put("code","user.notexist"); map.put("message",e.getMessage()); return "forward:/error"; }

为什么浏览器还是空白页面？

通过解析error的status_code 来决定跳转的视图名

传入HttpServletRequest，设置状态码

修改自定的异常处理，传入HttpServletRequest，并设置错误状态码

//@ResponseBody @ExceptionHandler(UserNotExistException.class) public String handleException(Exception e, HttpServletRequest request){ Map<String,Object> map = new HashMap<>(); request.setAttribute("javax.servlet.error.status_code",500); //存放自己的错误代码 map.put("code","user.notexist"); map.put("message",e.getMessage()); return "forward:/error"; }

测试

携带定制的错误数据

DefaultErrorAttributes 默认进行错误数据处理

DefaultErrorAttributes implements ErrorAttributes, HandlerExceptionResolver, Ordered

在ErrorMvcAutoConfiguration中：

@Bean @ConditionalOnMissingBean(value = ErrorAttributes.class, search = SearchStrategy.CURRENT) public DefaultErrorAttributes errorAttributes() { return new DefaultErrorAttributes(); }

注意到使用了@ConditionalOnMissingBean，所以我们可以自己向容器中注入自定义的ErrorArributes，来修改默认行为。

@Component public class MyErrorAttributes extends DefaultErrorAttributes { @Override public Map<String, Object> getErrorAttributes(WebRequest webRequest, ErrorAttributeOptions options) { Map<String, Object> attributes = super.getErrorAttributes(webRequest, options); attributes.put("company","EzerbelCN"); return attributes; } }

测试

添加扩展的异常数据信息

//@ResponseBody @ExceptionHandler(UserNotExistException.class) public String handleException(Exception e, HttpServletRequest request){ Map<String,Object> map = new HashMap<>(); request.setAttribute("javax.servlet.error.status_code",500); //存放自己的错误代码 map.put("code","user.notexist"); map.put("message",e.getMessage()); request.setAttribute("ext",map); return "forward:/error"; }

解析扩展的异常数据信息

@Component public class MyErrorAttributes extends DefaultErrorAttributes { @Override public Map<String, Object> getErrorAttributes(WebRequest webRequest, ErrorAttributeOptions options) { Map<String, Object> attributes = super.getErrorAttributes(webRequest, options); attributes.put("company","EzerbelCN"); // SCOPE_REQUEST = 0 // SCOPE_SESSION = 1 // 前面ext被存在了request域中，所以要去request域 scope = 0 中获取 Map<String,Object> ext = (Map<String, Object>) webRequest.getAttribute("ext",0); if (ext != null) { attributes.put("ext",ext); } return attributes; } }

异常显示页面

<main role="main" class="col-md-9 ml-sm-auto col-lg-10 pt-3 px-4"> <h1>5xx-----status:[[${status}]]</h1> <h2>5xx-----timestamp:[[${timestamp}]]</h2> <h2>5xx-----exception:[[${exception}]]</h2> <h2>5xx-----message:[[${message}]]</h2> <h2>5xx-----ext.code:[[${ext.code}]]</h2> <h2>5xx-----ext.message:[[${ext.message}]]</h2> </main>