Sie können diese Exceptionhandler mit Ihren eigenen überschreiben.

### Überschreiben von Request-Validierungs-Exceptions { #override-request-validation-exceptions }

Wenn ein Request ungültige Daten enthält, löst **FastAPI** intern einen `RequestValidationError` aus.

Und es enthält auch einen Default-Exceptionhandler für diesen.

 *
 * Performance optimizations:
 * - Uses ConcurrentLinkedQueue for O(1) operations
 * - Lock-free operations for better concurrency
 * - Proper buffer validation and limits
 */
public class BufferCache {

    /**
     * Private constructor to prevent instantiation of this utility class.
     */
    private BufferCache() {
        // Utility class - not instantiable

使用上面的任何方法，它在 `/docs` 中看起来都是这样的:

<img src="/img/tutorial/body-fields/image01.png">

## 技术细节

关于 `example` 和 `examples`...

JSON Schema在最新的一个版本中定义了一个字段 <a href="https://json-schema.org/draft/2019-09/json-schema-validation.html#rfc.section.9.5" class="external-link" target="_blank">`examples`</a> ，但是 OpenAPI 基于之前的一个旧版JSON Schema，并没有 `examples`.

            this.message = message;
            return this;
        }

        /**
         * Sets the error message from validation messages.
         * @param validationMessagesLambda Lambda function to process validation messages.
         * @return This ApiErrorResponse instance.
         */
        public ApiErrorResponse message(final VaMessenger<FessMessages> validationMessagesLambda) {

        assertEquals(3, third.length, "Allocated buffer length matches configured maximum size");
    }

    // Parameterized: exercise small variations of cache size for a simple reuse cycle
    @ParameterizedTest
    @ValueSource(ints = { 1, 2 })
    @DisplayName("Parameterized: buffer reuse works for various small cache sizes")

                                    }
                                },
                            },
                            "422": {
                                "description": "Validation Error",
                                "content": {
                                    "application/json": {
                                        "schema": {

                                "content": {"application/json": {"schema": {}}},
                            },
                            "422": {
                                "description": "Validation Error",
                                "content": {
                                    "application/json": {
                                        "schema": {

                                        }
                                    }
                                },
                                "description": "Validation Error",
                            },
                        },
                        "summary": "Get Facility",
                    }
                }
            },
        }

     */
    public void setPreloadSize(final int preloadSize) {
        this.preloadSize = preloadSize;
    }

    /**
     * Enables or disables validation of sitemap entries.
     * @param enableValidation true to enable validation, false to disable
     */
    public void setEnableValidation(final boolean enableValidation) {
        this.enableValidation = enableValidation;
    }

    /**

if exist "%USERPROFILE%\mavenrc_pre.cmd" call "%USERPROFILE%\mavenrc_pre.cmd" %*
if exist "%USERPROFILE%\mavenrc.cmd" call "%USERPROFILE%\mavenrc.cmd" %*
:skipRc

@setlocal

set ERROR_CODE=0

@REM ==== START VALIDATION ====
if not "%JAVA_HOME%"=="" goto javaHomeSet
for %%i in (java.exe) do set "JAVACMD=%%~$PATH:i"
goto checkJavaCmd

:javaHomeSet
set "JAVACMD=%JAVA_HOME%\bin\java.exe"

if not exist "%JAVACMD%" (