SpringBoot 异常处理/自定义格式校验的问题实例详解

@Validated // 必需
@RestController
public class ProductController {
    @GetMapping("/products")
    public Product getProduct(@ValidCategory String category) {
        // ...
    }
}

@PostMapping("/products")
public ResponseEntity<?> createProduct(
    @Valid @RequestBody ProductRequest request // 触发验证
) {
    // ...
}

@ValidInventory // 类级别约束
public class Product {
    private int stockQuantity;
    private int minStockLevel;
}
@PostMapping("/products")
public ResponseEntity<?> createProduct(
    @Valid @RequestBody Product product // 触发验证
) {
    // ...
}

@ExceptionHandler(MethodArgumentNotValidException.class)
public ResponseEntity<String> handleValidationException(MethodArgumentNotValidException ex) {
    // 只获取字段错误
    String errorMsg = ex.getBindingResult().getFieldErrors().stream()
            .map(fieldError -> fieldError.getField() + ": " + fieldError.getDefaultMessage())
            .collect(Collectors.joining("; "));
    log.warn("请求值验证异常 | request={}", ex.getMessage());
    return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(errorMsg);
}

@ExceptionHandler(MethodArgumentNotValidException.class)
public ResponseEntity<String> handleValidationException(MethodArgumentNotValidException ex) {
    // 只获取字段错误
    String errorMsg = ex.getBindingResult().getGlobalErrors().stream()
            .map(DefaultMessageSourceResolvable::getDefaultMessage)
            .collect(Collectors.joining("; "));
    log.warn("请求值验证异常 | request={}", ex.getMessage());
    return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(errorMsg);
}

@ExceptionHandler(MethodArgumentNotValidException.class)
public ResponseEntity<String> handleValidationException(MethodArgumentNotValidException ex) {
    // 创建错误消息列表
    List<String> errorMessages = new ArrayList<>();
    // 处理字段错误
    ex.getBindingResult().getFieldErrors().forEach(fieldError -> {
        String msg = String.format("%s: %s",
                fieldError.getField(),
                fieldError.getDefaultMessage());
        errorMessages.add(msg);
    });
    // 处理全局错误
    ex.getBindingResult().getGlobalErrors().forEach(globalError -> {
        String msg = String.format("全局错误: %s", globalError.getDefaultMessage());
        errorMessages.add(msg);
    });
    // 合并所有错误消息
    String errorMsg = String.join("; ", errorMessages);
    return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(errorMsg);
}

public String getMessage() {
    StringBuilder sb = new StringBuilder("Validation failed for argument at index ")
            .append(getParameter().getParameterIndex()).append(" in method: ")
            .append(getParameter().getExecutable().toGenericString());
    BindingResult result = getBindingResult();
    if (result.getErrorCount() > 0) {
        sb.append(", with ").append(result.getErrorCount()).append(" error(s): ");
        for (ObjectError error : result.getAllErrors()) {
            sb.append('[').append(error).append("] ");
        }
    }
    return sb.toString();
}