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福州网站建设服务平台,上海牛巨微seo,中国设计师排名,鱼馆网站的前期策划Java异常处理与全局异常处理全面指南一、Java异常处理基础 1. 异常分类 Java中的异常分为两大类： Checked Exception（检查型异常）：必须被捕获或声明抛出，如IOException、SQLExceptionUnchecked Exception&#xf…

Java异常处理与全局异常处理全面指南

一、Java异常处理基础

1. 异常分类

Java中的异常分为两大类：

Checked Exception（检查型异常）：必须被捕获或声明抛出，如IOException、SQLException
Unchecked Exception（非检查型异常）：RuntimeException及其子类，如NullPointerException、ArrayIndexOutOfBoundsException

2. 基本异常处理语法

try {// 可能抛出异常的代码
} catch (SpecificException e) {// 处理特定异常
} catch (GeneralException e) {// 处理更一般的异常
} finally {// 无论是否发生异常都会执行的代码
}

3. 异常处理最佳实践

不要忽略异常：空的catch块是"罪恶"的
优先处理最具体的异常
合理使用finally释放资源
考虑使用try-with-resources（Java 7+）
避免在finally块中使用return

二、Spring全局异常处理机制

1. @ControllerAdvice + @ExceptionHandler

@ControllerAdvice
public class GlobalExceptionHandler {@ExceptionHandler(Exception.class)public ResponseEntity<ErrorResponse> handleAllExceptions(Exception ex) {ErrorResponse error = new ErrorResponse("SERVER_ERROR", "An unexpected error occurred",HttpStatus.INTERNAL_SERVER_ERROR.value());return new ResponseEntity<>(error, HttpStatus.INTERNAL_SERVER_ERROR);}@ExceptionHandler(ResourceNotFoundException.class)public ResponseEntity<ErrorResponse> handleResourceNotFound(ResourceNotFoundException ex) {ErrorResponse error = new ErrorResponse("NOT_FOUND", ex.getMessage(),HttpStatus.NOT_FOUND.value());return new ResponseEntity<>(error, HttpStatus.NOT_FOUND);}
}

2. 自定义异常类

public class BusinessException extends RuntimeException {private String errorCode;private HttpStatus httpStatus;public BusinessException(String message, String errorCode, HttpStatus httpStatus) {super(message);this.errorCode = errorCode;this.httpStatus = httpStatus;}// getters
}

3. 统一响应格式

@Data
@AllArgsConstructor
@NoArgsConstructor
public class ErrorResponse {private String errorCode;private String message;private int status;private long timestamp;private String path;private List<ValidationError> validationErrors;public ErrorResponse(String errorCode, String message, int status) {this.errorCode = errorCode;this.message = message;this.status = status;this.timestamp = System.currentTimeMillis();}
}@Data
@AllArgsConstructor
public class ValidationError {private String field;private String message;
}

三、高级异常处理技巧

1. 处理验证异常（Validation）

@ExceptionHandler(MethodArgumentNotValidException.class)
public ResponseEntity<ErrorResponse> handleValidationExceptions(MethodArgumentNotValidException ex) {List<ValidationError> errors = ex.getBindingResult().getFieldErrors().stream().map(error -> new ValidationError(error.getField(), error.getDefaultMessage())).collect(Collectors.toList());ErrorResponse error = new ErrorResponse("VALIDATION_FAILED","Validation failed for one or more fields",HttpStatus.BAD_REQUEST.value(),errors);return new ResponseEntity<>(error, HttpStatus.BAD_REQUEST);
}

2. 国际化异常消息

@ExceptionHandler(BusinessException.class)
public ResponseEntity<ErrorResponse> handleBusinessException(BusinessException ex, WebRequest request,Locale locale) {String message = messageSource.getMessage(ex.getMessageKey(), ex.getArgs(), locale);ErrorResponse error = new ErrorResponse(ex.getErrorCode(),message,ex.getHttpStatus().value());return new ResponseEntity<>(error, ex.getHttpStatus());
}

3. 日志记录策略

@ExceptionHandler(Exception.class)
public ResponseEntity<ErrorResponse> handleAllExceptions(Exception ex, WebRequest request) {logger.error("Unexpected error occurred: {}", ex.getMessage(), ex);ErrorResponse error = new ErrorResponse("SERVER_ERROR","An unexpected error occurred",HttpStatus.INTERNAL_SERVER_ERROR.value(),request.getDescription(false));return new ResponseEntity<>(error, HttpStatus.INTERNAL_SERVER_ERROR);
}

四、实战建议

分层异常处理：
- 控制器层：处理HTTP相关异常
- 服务层：处理业务逻辑异常
- 数据访问层：处理数据相关异常
异常转换：将底层异常转换为上层业务异常
异常信息设计：
- 包含足够的信息用于调试
- 不暴露敏感信息
- 提供明确的错误代码
监控与报警：对关键异常设置监控报警
文档化：为API消费者提供清晰的错误代码和含义文档

五、常见问题解决方案

处理404错误：

@ControllerAdvice
public class CustomErrorController implements ErrorController {@RequestMapping("/error")public ResponseEntity<ErrorResponse> handleError(HttpServletRequest request) {Integer status = (Integer) request.getAttribute("javax.servlet.error.status_code");Exception exception = (Exception) request.getAttribute("javax.servlet.error.exception");ErrorResponse error = new ErrorResponse("NOT_FOUND","Requested resource not found",status);return new ResponseEntity<>(error, HttpStatus.valueOf(status));}
}

处理跨域异常：

@ExceptionHandler
public ResponseEntity<ErrorResponse> handleCorsException(CorsException ex) {ErrorResponse error = new ErrorResponse("CORS_ERROR",ex.getMessage(),HttpStatus.FORBIDDEN.value());return new ResponseEntity<>(error, HttpStatus.FORBIDDEN);
}

处理文件上传大小限制异常：

@ExceptionHandler(MaxUploadSizeExceededException.class)
public ResponseEntity<ErrorResponse> handleMaxSizeException(MaxUploadSizeExceededException exc) {ErrorResponse error = new ErrorResponse("FILE_TOO_LARGE","File size exceeds the allowed limit",HttpStatus.BAD_REQUEST.value());return new ResponseEntity<>(error, HttpStatus.BAD_REQUEST);
}