Spring Boot 中自定义异常处理

缺乏、安全感 2022-01-09 23:27 299阅读 0赞

# Spring Boot 中自定义异常处理 #

*  项目地址[https://github.com/helloworlde/SpringBootCollection/tree/master/SpringBoot-Exception][https_github.com_helloworlde_SpringBootCollection_tree_master_SpringBoot-Exception]

> Spring Boot 中提供了默认的异常处理，但是对于应用来说，这些信息并不应该直接返回或者不够明确，需要结合自己的情况进行定制  
> 自定义处理异常有两种方式:
> 
>  *  `org.springframework.web.servlet.HandlerExceptionResolver#resolveException`方法
>  *  `org.springframework.web.bind.annotation.RestControllerAdvice`或`org.springframework.web.bind.annotation.ControllerAdvice`和`org.springframework.web.bind.annotation.ExceptionHandler`注解来实现

> 当两种方式都实现时，`HandlerExceptionResolver`要先于`ControllerAdvice`执行

## 使用 HandlerExceptionResolver 处理异常 ##

*  CustomExceptionHandlerResolver.java

public class CustomExceptionHandlerResolver implements HandlerExceptionResolver { 
    
        private static final ObjectMapper OBJECT_MAPPER;
    
        static { 
            OBJECT_MAPPER = new ObjectMapper();
            OBJECT_MAPPER.configure(JsonParser.Feature.ALLOW_SINGLE_QUOTES, true);
            OBJECT_MAPPER.configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);
            OBJECT_MAPPER.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
        }
    
        @Override
        public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) { 
    
            String message = "服务器错误";
    
            if (o instanceof HandlerMethod) { 
                if (e instanceof IllegalArgumentException) { 
                    message = "参数错误";
                } else if (e instanceof SecurityException) { 
                    message = "不允许访问";
                } else if (e instanceof NullPointerException) { 
                    message = "空指针异常";
                }
            } else if (e instanceof NoHandlerFoundException) { 
                message = "未找到相应资源";
            } else if (e instanceof HttpMediaTypeNotSupportedException) { 
                message = "请求类型不支持";
            }
    
            httpServletResponse.setCharacterEncoding(StandardCharsets.UTF_8.name());
            httpServletResponse.setContentType(MediaType.APPLICATION_JSON_UTF8_VALUE);
    
            try { 
                httpServletResponse.getWriter()
                                   .write(
                                           OBJECT_MAPPER.writeValueAsString(
                                                   CustomResponseContent.builder()
                                                                        .code(500)
                                                                        .status("fail")
                                                                        .message(message)
                                                                        .build()
                                           )
                                   );
            } catch (IOException ex) { 
                ex.printStackTrace();
            }
    
            return new ModelAndView();
        }
    }

还需要将该配置添加到应用中

*  CustomWebMvcConfigurer.java

@Configuration
    public class CustomWebMvcConfigurer implements WebMvcConfigurer { 
    
        @Override
        public void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) { 
            resolvers.add(new CustomExceptionHandlerResolver());
        }
    }

### 测试 ###

*  添加接口

*  调用接口

curl localhost:8080/null
    {"code":500,"status":"fail","data":null,"message":"空指针异常"}%
    
    curl localhost:8080/arg
    {"code":500,"status":"fail","data":null,"message":"参数错误"}%

## 使用 RestControllerAdvice/ControllerAdvice 和 ExceptionHandler 处理异常 ##

*  CustomControllerExceptionResolver.java

@RestControllerAdvice
    @ControllerAdvice
    public class CustomControllerExceptionResolver { 
    
        @ExceptionHandler({ NullPointerException.class})
        @ResponseBody
        public ResponseEntity<?> handlerNullPointerException(HttpServletRequest request, Throwable throwable) { 
            CustomResponseContent responseContent = CustomResponseContent.builder()
                                                                         .code(500)
                                                                         .status("fail")
                                                                         .message("空指针异常")
                                                                         .build();
            return new ResponseEntity<>(responseContent, HttpStatus.INTERNAL_SERVER_ERROR);
        }
    
        @ExceptionHandler({ IllegalArgumentException.class})
        @ResponseBody
        public ResponseEntity<?> handlerIllegalArgumentException(HttpServletRequest request, Throwable throwable) { 
            CustomResponseContent responseContent = CustomResponseContent.builder()
                                                                         .code(400)
                                                                         .status("fail")
                                                                         .message("参数错误")
                                                                         .build();
            return new ResponseEntity<>(responseContent, HttpStatus.BAD_REQUEST);
        }
    
        @ExceptionHandler({ MethodArgumentNotValidException.class})
        @ResponseBody
        public ResponseEntity<?> handlerMethodArgumentNotValidException(HttpServletRequest request, MethodArgumentNotValidException e) { 
            String errorMessage = e.getBindingResult()
                                   .getAllErrors()
                                   .stream()
                                   .map(f -> ((FieldError) f).getField() + ":" + f.getDefaultMessage())
                                   .collect(Collectors.joining(";"));
    
            CustomResponseContent responseContent = CustomResponseContent.builder()
                                                                         .code(400)
                                                                         .status("fail")
                                                                         .message(errorMessage)
                                                                         .build();
            return new ResponseEntity<>(responseContent, HttpStatus.BAD_REQUEST);
        }
        
        @ExceptionHandler({ Exception.class})
        @ResponseBody
        public ResponseEntity<?> handlerException(HttpServletRequest request, Throwable throwable) { 
            CustomResponseContent responseContent = CustomResponseContent.builder()
                                                                         .code(500)
                                                                         .status("fail")
                                                                         .message(throwable.getMessage())
                                                                         .build();
            return new ResponseEntity<>(responseContent, HttpStatus.INTERNAL_SERVER_ERROR);
        }
    }

### 测试 ###

*  添加接口

@GetMapping("/null")
        @CustomResponse
        public Object getProduct() { 
            throw new NullPointerException();
        }
    
        @GetMapping("/arg")
        public Object getProducts() { 
            throw new IllegalArgumentException();
        }
    
        @PostMapping("/product")
        @CustomResponse
        public Product product(@RequestBody @Validated Product product) { 
            return product;
        }

*  添加接口参数校验

@Data
    @Builder
    @NoArgsConstructor
    @AllArgsConstructor
    public class Product implements Serializable { 
    
        private static final Long serialVersionUID = 1435515995276255188L;
    
    
        @NotNull(message = "id 不能为空")
        @Min(value = 1, message = "id 必须大于0")
        @Max(value = 10, message = "id 不能小于 10")
        private Long id;
    
        @NotNull(message = "名称不能为空")
        @Pattern(regexp = "product[\\w]+", message = "名称必须以 product 开头")
        private String name;
    
        @PositiveOrZero(message = "价格必须是正数")
        private Long price;
    
    }

*  测试

curl localhost:8080/null
    { "code":500,"status":"fail","data":null,"message":"空指针异常"}%
    
    curl localhost:8080/arg
    { "code":400,"status":"fail","data":null,"message":"参数错误"}%
    
    
    curl -X POST \
      http://localhost:8080/product \
      -H 'Content-Type: application/json' \
      -d '{ "id": 1 }'
    { "code":400,"status":"fail","data":null,"message":"name:名称不能为空"}%
    
    
    curl -X POST \
      http://localhost:8080/product \
      -H 'Content-Type: application/json' \
      -d '{ "id": 0, "name": 1, "price": -100 }'
    { "code":400,"status":"fail","data":null,"message":"id:id 必须大于0;price:价格必须是正数;name:名称必须以 product 开头"}%

## 403/404… 等错误 ##

添加了上述的异常处理后，还有一部分异常无法处理，如404 错误，这是因为这些错误的异常处理并不经过异常处理器，而是被转发到 `/error`的路径下，默认由`org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController`处理，所以，继承`org.springframework.boot.autoconfigure.web.servlet.error.AbstractErrorController`并添加相应实现即可自定义处理该异常

### 返回 JSON 数据 ###

*  CustomNoHandlerExceptionResolver.java

@Controller
    @RequestMapping("/error")
    public class CustomNoHandlerExceptionResolver extends AbstractErrorController { 
    
        public CustomNoHandlerExceptionResolver(ErrorAttributes errorAttributes) { 
            super(errorAttributes);
        }
    
        @Override
        public String getErrorPath() { 
            return null;
        }
    
        @RequestMapping
        @ResponseBody
        public ResponseEntity<?> error(HttpServletRequest request, HttpServletResponse response) { 
            Optional<String> originRequestUri = Optional.ofNullable((String) request.getAttribute("javax.servlet.error.request_uri"));
            String reasonPhrase = HttpStatus.valueOf(response.getStatus()).getReasonPhrase();
    
            CustomResponseContent responseContent = CustomResponseContent.builder()
                                                                         .code(response.getStatus())
                                                                         .status("fail")
                                                                         .message(originRequestUri.orElse("/error") + ":" + reasonPhrase)
                                                                         .build();
    
            return new ResponseEntity<>(responseContent, HttpStatus.valueOf(response.getStatus()));
        }
    }

*  测试

curl localhost:8080/404
    { "code":404,"status":"fail","data":null,"message":"/404:Not Found"}%

### 返回错误页面 ###

当通过页面访问时，我们希望返回一个页面，可以通过指定 `produces="text/html"`处理来自网页的请求

在`resources/public/error`目录下添加相应的文件，如 `404.html`等，根据不同的错误返回相应的页面

@RequestMapping(produces = MediaType.TEXT_HTML_VALUE)
        public ModelAndView pageError(HttpServletRequest request, HttpServletResponse response) { 
            return new ModelAndView(String.format("error/%d.html", response.getStatus()));
        }

[https_github.com_helloworlde_SpringBootCollection_tree_master_SpringBoot-Exception]: https://github.com/helloworlde/SpringBootCollection/tree/master/SpringBoot-Exception