response.readDataWireFormat(buffer, 0, buffer.length);
        });
    }

    @Test
    @DisplayName("Test toString method")
    void testToString() {
        String result = response.toString();
        assertNotNull(result);
        // The toString method includes various parameter information
        assertTrue(result.contains("totalParameterCount"));

      <span style="background-color:#007166"><font color="#D3D7CF"> app </font></span>  Using import string: <font color="#3465A4">main:app</font>

   <span style="background-color:#007166"><font color="#D3D7CF"> server </font></span>  Server started at <font color="#729FCF"><u style="text-decoration-style:solid">http://0.0.0.0:8000</u></font>

      <span style="background-color:#007166"><font color="#D3D7CF"> app </font></span>  Using import string: <font color="#3465A4">main:app</font>

   <span style="background-color:#007166"><font color="#D3D7CF"> server </font></span>  Server started at <font color="#729FCF"><u style="text-decoration-style:solid">http://0.0.0.0:8000</u></font>

        }
    ]
}
```

вы получите текстовую версию:

```
Validation errors:
Field: ('path', 'item_id'), Error: Input should be a valid integer, unable to parse string as an integer
```

### Переопределите обработчик ошибок `HTTPException` { #override-the-httpexception-error-handler }

Аналогичным образом можно переопределить обработчик `HTTPException`.

      <span style="background-color:#007166"><font color="#D3D7CF"> app </font></span>  Using import string: <font color="#3465A4">main:app</font>

   <span style="background-color:#007166"><font color="#D3D7CF"> server </font></span>  Server started at <font color="#729FCF"><u style="text-decoration-style:solid">http://0.0.0.0:8000</u></font>

# 查詢參數與字串驗證 { #query-parameters-and-string-validations }

FastAPI 允許你為參數宣告額外的資訊與驗證。

以下面這個應用為例：

{* ../../docs_src/query_params_str_validations/tutorial001_py310.py hl[7] *}

查詢參數 `q` 的型別是 `str | None`，表示它是 `str` 但也可以是 `None`，而且預設值就是 `None`，因此 FastAPI 會知道它不是必填。

/// note | 注意

FastAPI 會因為預設值是 `= None` 而知道 `q` 不是必填。

使用 `str | None` 也能讓你的編輯器提供更好的支援並偵測錯誤。

///

## 額外驗證 { #additional-validation }

   */
  // TODO(b/65488446): Make this a public API.
  private static ImmutableList<URL> parseJavaClassPath() {
    ImmutableList.Builder<URL> urls = ImmutableList.builder();
    for (String entry : Splitter.on(PATH_SEPARATOR.value()).split(JAVA_CLASS_PATH.value())) {
      try {
        try {
          urls.add(new File(entry).toURI().toURL());

      } catch (InvocationTargetException e) {
        throw Throwables.propagate(e.getCause());
      }
      assertEquals("Failed to forward to " + method, 1, called.get());
    }

    @Override
    public String toString() {
      return "dummy " + interfaceType.getSimpleName();
    }
  }

   * {@link #iterator}, you may wish to override {@link #toString} to forward to this
   * implementation.
   *
   * @since 7.0
   */
  protected String standardToString() {
    return Collections2.toStringImpl(this);
  }

  /**
   * A sensible definition of {@link #toArray()} in terms of {@link #toArray(Object[])}. If you

   * {@link #iterator}, you may wish to override {@link #toString} to forward to this
   * implementation.
   *
   * @since 7.0
   */
  protected String standardToString() {
    return Collections2.toStringImpl(this);
  }

  /**
   * A sensible definition of {@link #toArray()} in terms of {@link #toArray(Object[])}. If you