Spring Boot -- 異常處理

• 預設的異常處理
• 自定義的異常處理
• BasicErrorController 方式
• @ExceptionHandler 註解方式

預設的異常處理

預設的異常處理有兩種方式

• BasicErrorController 方式
• @ExceptionHandler 註解方式

在Spring boot開發中經常遇到“Whitelabel Error Page”白色標籤錯誤頁，這個頁面當spring boot中發生錯誤時的預設處理方式，返回一個error頁面，而這個頁面的格式是固定的，這個頁面有幾個變數，對映地址:/error, status=404,type=Not Found。
SpringBoot的預設錯誤處理是BasicErrorController，支援兩種格式：

• 錯誤頁面 errorHtml
• json響應 error

Spring Boot預設的異常處理原始碼(BasicErrorController)

@RequestMapping(
    produces = {"text/html"}
)
public ModelAndView errorHtml(HttpServletRequest request, HttpServletResponse response) {
    HttpStatus status = this.getStatus(request);
    Map model = Collections.
 
unmodifiableMap(this.getErrorAttributes(request, this.isIncludeStackTrace(request, MediaType.TEXT_HTML)));
    response.setStatus(status.value());
    ModelAndView modelAndView = this.resolveErrorView(request, response, status, model);
    return modelAndView != null?modelAndView:new ModelAndView("error"
 
, model);
}

@RequestMapping
@ResponseBody
public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
    Map body = this.getErrorAttributes(request, this.isIncludeStackTrace(request, MediaType.ALL));
    HttpStatus status = this.getStatus(request);
    return new ResponseEntity(body, status);
}

errorHtml()返回錯誤頁面
error()json響應錯誤

自定義的異常處理

BasicErrorController 方式

繼承BasicErrorController ,並重寫errorHtml()和error()

@Controller
public class DemoErrorController extends BasicErrorController {

    public DemoErrorController(ServerProperties serverProperties){
        super(new DefaultErrorAttributes(), serverProperties.getError());
    }

    @Override
    public ModelAndView errorHtml(HttpServletRequest request, HttpServletResponse response) {
        HttpStatus status = getStatus(request);
        response.setStatus(status.value());

        System.out.println("do DemoErrorController errorHtml ......");

        Map<String, Object> model = getErrorAttributes(request, isIncludeStackTrace(request, MediaType.TEXT_HTML));
        ModelAndView modelAndView = resolveErrorView(request, response, status, model);
        return (modelAndView == null ? new ModelAndView("error", model) : modelAndView);
    }

    @Override
    public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
        HttpStatus status = getStatus(request);
        Map<String, Object> body = getErrorAttributes(request, isIncludeStackTrace(request, MediaType.ALL));

        //輸出自定義的Json格式
        Map<String, Object> map = new HashMap<>();
        map.put("success", false);
        map.put("msg", body.get("message"));

        System.out.println("do DemoErrorController error ......");

        return new ResponseEntity<>(map, status);
    }
}

@ExceptionHandler 註解方式

通過AOP切面對controller進行異常植入
@ExceptionHandler的value定義的是要匹配的異常型別，這裡寫了一個總的異常Exception，可以針對某個具體的異常進行處理。

@ControllerAdvice
public class AllExceptionHandle {

    @ExceptionHandler(value = Exception.class)
    public ModelAndView errorHtmlHandle(HttpServletRequest request, Exception e) throws Exception{
        System.out.println("do AllExceptionHandle errorHtmlHandle ......");
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.addObject("exception", e);
        modelAndView.addObject("url", request.getRequestURL());
        modelAndView.setViewName("error");
        return modelAndView;
    }

    @ExceptionHandler(value = NullPointerException.class)
    public Map<String, Object> errorJsonHandle(HttpServletRequest request, Exception e) throws Exception{
        System.out.println("do AllExceptionHandle errorJsonHandle ......");
        Map<String, Object> map = new HashMap<>();
        map.put("exception", e);
        map.put("url", request.getRequestURL());
        return map;
    }
}

轉載
Spring Boot入門教程(二十一): 異常處理