# 请求体 - 多个参数

既然我们已经知道了如何使用 `Path` 和 `Query`，下面让我们来了解一下请求体声明的更高级用法。

## 混合使用 `Path`、`Query` 和请求体参数

首先，毫无疑问地，你可以随意地混合使用 `Path`、`Query` 和请求体参数声明，**FastAPI** 会知道该如何处理。

你还可以通过将默认值设置为 `None` 来将请求体参数声明为可选参数：

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

/// note

请注意，在这种情况下，将从请求体获取的 `item` 是可选的。因为它的默认值为 `None`。

///

## 多个请求体参数

在上面的示例中，*路径操作*将期望一个具有 `Item` 的属性的 JSON 请求体，就像：

```JSON

from typing import Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Union[str, None] = Query(
        default=None, min_length=3, max_length=50, pattern="^fixedquery$"
    ),
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

        cb.query().addOrderBy_SortOrder_Asc();
        cb.query().addOrderBy_Name_Asc();
        // search

    }

    /**
     * Gets a list of all role types.
     * @return A list of all role types.
     */
    public List<RoleType> getRoleTypeList() {
        return roleTypeBhv.selectList(cb -> {
            cb.query().addOrderBy_SortOrder_Asc();
            cb.query().addOrderBy_Name_Asc();

It includes:

* `Query()`
* `Path()`
* `Body()`
* `Cookie()`
* `Header()`
* `Form()`
* `File()`

You can import them all directly from `fastapi`:

```python
from fastapi import Body, Cookie, File, Form, Header, Path, Query
```

::: fastapi.Query

::: fastapi.Path

::: fastapi.Body

::: fastapi.Cookie

):
    await websocket.accept()
    while True:
        data = await websocket.receive_text()
        await websocket.send_text(
            f"Session cookie or query token value is: {cookie_or_token}"
        )
        if q is not None:
            await websocket.send_text(f"Query parameter q is: {q}")

    // ===================================================================================
    //                                                                               Query
    //                                                                               =====
    public BsFileConfigCQ query() {
        assertQueryPurpose();
        return doGetConditionQuery();
    }

    protected BsFileConfigCQ doGetConditionQuery() {

                                ],
                                "title": "Query string",
                                "description": "Query string for the items to search in the database that have a good match",
                            },
                            "name": "q",
                            "in": "query",
                        }
                    ],
                }
            }

from fastapi import FastAPI, Query
from pydantic import BaseModel, Field

app = FastAPI()


class FilterParams(BaseModel):
    limit: int = Field(100, gt=0, le=100)
    offset: int = Field(0, ge=0)
    order_by: Literal["created_at", "updated_at"] = "created_at"
    tags: list[str] = []


@app.get("/items/")
async def read_items(filter_query: Annotated[FilterParams, Query()]):

        request.setSize(size);
        return this;
    }

    /**
     * Sets the query string for the request.
     * @param query The query string.
     * @return This builder instance.
     */
    public SuggestRequestBuilder setQuery(final String query) {
        request.setQuery(query);
        return this;
    }

    /**
     * Adds a tag to filter by.
     * @param tag The tag.

        return writer -> {
            final SearchLogBhv bhv = ComponentUtil.getComponent(SearchLogBhv.class);
            bhv.selectCursor(cb -> {
                cb.query().matchAll();
                cb.query().addOrderBy_RequestedAt_Asc();
            }, new LogEntityRowHandler<SearchLog>() {
                @Override
                public void handle(final SearchLog entity) {