Spring Boot中@PathVariable参数验证与异常处理实践

import org.springframework.http.ResponseEntity;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.validation.Valid;
import javax.validation.constraints.Min;
import java.util.List;

@RestController
@Validated // 关键：使方法参数上的验证注解生效
@RequestMapping("/api/v1")
public class EmployeeController {

    @GetMapping("/employees/{limit}")
    public ResponseEntity<ApiResponse<List<Employee>>> findTopNEmployeeBySalary(
            @PathVariable("limit") @Valid @Min(1) int limit) {
        // 业务逻辑：根据limit查询员工列表
        // ... 假设这里返回一个ApiResponse对象
        return ResponseEntity.ok(new ApiResponse<>("Success", List.of()));
    }

    // 示例辅助类，实际项目中应有完整定义
    static class Employee { /* ... */ }
    static class ApiResponse<T> {
        String message;
        T data;
        public ApiResponse(String message, T data) {
            this.message = message;
            this.data = data;
        }
    }
}

{
    "timestamp": "2023-10-27T10:30:00.000+00:00",
    "status": 500,
    "error": "Internal Server Error",
    "path": "/api/v1/employees/-21"
}

javax.validation.ConstraintViolationException: findTopNEmployeeBySalary.limit: must be greater than or equal to 1
    at org.springframework.validation.beanvalidation.MethodValidationInterceptor.invoke(MethodValidationInterceptor.java:125)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:350)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:693)
    // ... 更多堆栈信息

import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.context.request.WebRequest;

import javax.validation.ConstraintViolation;
import javax.validation.ConstraintViolationException;
import java.time.LocalDateTime;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;

@ControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(ConstraintViolationException.class)
    public ResponseEntity<Object> handleConstraintViolationException(
            ConstraintViolationException ex, WebRequest request) {

        Map<String, Object> body = new LinkedHashMap<>();
        body.put("timestamp", LocalDateTime.now());
        body.put("status", HttpStatus.BAD_REQUEST.value());

        // 提取所有验证错误信息
        Set<String> errors = ex.getConstraintViolations().stream()
                .map(ConstraintViolation::getMessage)
                .collect(Collectors.toSet());

        body.put("errors", errors);
        body.put("message", "Validation failed for path variables or request parameters.");
        body.put("path", request.getDescription(false).replace("uri=", ""));

        return new ResponseEntity<>(body, HttpStatus.BAD_REQUEST);
    }

    // 针对@RequestBody验证失败的异常处理，通常是MethodArgumentNotValidException
    // @ExceptionHandler(MethodArgumentNotValidException.class)
    // public ResponseEntity<Object> handleMethodArgumentNotValid(
    //         MethodArgumentNotValidException ex, HttpHeaders headers, HttpStatus status, WebRequest request) {
    //     // ... 类似处理
    // }

    // 也可以添加其他通用异常处理
    // @ExceptionHandler(Exception.class)
    // public ResponseEntity<Object> handleAllExceptions(Exception ex, WebRequest request) {
    //     // ...
    // }
}

{
    "timestamp": "2023-10-27T10:30:00.000+00:00",
    "status": 400,
    "errors": [
        "must be greater than or equal to 1"
    ],
    "message": "Validation failed for path variables or request parameters.",
    "path": "/api/v1/employees/-21"
}