# Body - Multiple Parameters { #body-multiple-parameters }

Now that we have seen how to use `Path` and `Query`, let's see more advanced uses of request body declarations.

## Mix `Path`, `Query` and body parameters { #mix-path-query-and-body-parameters }

First, of course, you can mix `Path`, `Query` and request body parameter declarations freely and **FastAPI** will know what to do.

- If a heading contains only the name of a FastAPI feature, do not translate it.

### Quotes and punctuation

- Keep punctuation style consistent with existing Simplified Chinese docs (they often mix English terms like “FastAPI” with Chinese text).
- Never change punctuation inside inline code, code blocks, URLs, or file paths.

### Ellipsis

- Keep ellipsis style consistent within each document, prefer `...` over  `……`.

- Do not add trailing punctuation to headings.

### Quotes and punctuation

- Keep punctuation style consistent with existing Traditional Chinese docs (they often mix English terms like “FastAPI” with Chinese text).
- Never change punctuation inside inline code, code blocks, URLs, or file paths.

The same rules apply to dependencies.

Make sure blocking code is not run inside of `async` functions. The logic will work, but will damage the performance heavily.

When needing to mix blocking and async code, see Asyncer in [the other tools reference](references/other-tools.md).

## Streaming (JSON Lines, SSE, bytes)

        // Third: sb.length() > 0, add delimiter + "" (sb becomes "middle,")
        assertEquals("middle,", result);
    }

    @Test
    @DisplayName("Should handle mix of empty and null elements")
    void testJoinWithMixedEmptyAndNull() {
        String result = StringUtil.join("-", "", null, "value", "", null);
        // First: "" (sb becomes "")

		{"11 foo=bar\n\x00", "\x00", "foo", "bar", true},
		{"18 foo=b=\nar=\n==\x00\n", "", "foo", "b=\nar=\n==\x00", true},
		{"27 foo=hello9 foo=ba\nworld\n", "", "foo", "hello9 foo=ba\nworld", true},
		{"27 ☺☻☹=日a本b語ç\nmeow mix", "meow mix", "☺☻☹", "日a本b語ç", true},
		{"17 \x00hello=\x00world\n", "17 \x00hello=\x00world\n", "", "", false},
		{"1 k=1\n", "1 k=1\n", "", "", false},
		{"6 k~1\n", "6 k~1\n", "", "", false},

# 본문 - 다중 매개변수 { #body-multiple-parameters }

이제 `Path`와 `Query`를 어떻게 사용하는지 확인했으니, 요청 본문 선언에 대한 더 고급 사용법을 살펴보겠습니다.

## `Path`, `Query` 및 본문 매개변수 혼합 { #mix-path-query-and-body-parameters }

먼저, 물론 `Path`, `Query` 및 요청 본문 매개변수 선언을 자유롭게 혼합해서 사용할 수 있고, **FastAPI**는 어떤 동작을 할지 압니다.

또한 기본 값을 `None`으로 설정해 본문 매개변수를 선택사항으로 선언할 수 있습니다:

{* ../../docs_src/body_multiple_params/tutorial001_an_py310.py hl[18:20] *}

/// note | 참고

     */
    @Nonnull
    List<Node> getNodes();

    /**
     * Returns the file paths of all dependencies, regardless of which tool option those paths should be placed on.
     * The returned list may contain a mix of Java class path, Java module path, and other types of path elements.
     * This collection has the same content as {@code getDependencies.values()} except that it does not contain
     * null elements.
     *

# Body - 多個參數 { #body-multiple-parameters }

現在我們已經知道如何使用 `Path` 與 `Query`，接下來看看更進階的請求主體（request body）宣告用法。

## 混用 `Path`、`Query` 與 Body 參數 { #mix-path-query-and-body-parameters }

首先，當然你可以自由混用 `Path`、`Query` 與請求 Body 參數的宣告，**FastAPI** 會知道該怎麼做。

你也可以將 Body 參數宣告為可選，方法是將預設值設為 `None`：

{* ../../docs_src/body_multiple_params/tutorial001_an_py310.py hl[18:20] *}

/// note | 注意

請注意，在此情況下，從 body 取得的 `item` 是可選的，因為它的預設值是 `None`。

///

        assertEquals(1, param.getValues().length);
        assertEquals("onlyValue", param.getValues()[0]);
    }

    @Test
    public void test_constructor_withNullAndNonNullValues() {
        // Test with mix of null and non-null values
        String name = "mixedParam";
        String[] values = { "value1", null, "value3", null };
        RequestParameter param = new RequestParameter(name, values);