将请求体绑定到不同的结构体中
最后更新于：2022-04-02 07:27:21
绑定请求体的常规方法使用`c.Request.Body`，并且不能多次调用
```
type formA struct {
Foo string `json:"foo" xml:"foo" binding:"required"`
}
type formB struct {
Bar string `json:"bar" xml:"bar" binding:"required"`
}
func SomeHandler(c *gin.Context) {
objA := formA{}
objB := formB{}
// This c.ShouldBind consumes c.Request.Body and it cannot be reused.
if errA := c.ShouldBind(&objA); errA == nil {
c.String(http.StatusOK, `the body should be formA`)
// Always an error is occurred by this because c.Request.Body is EOF now.
} else if errB := c.ShouldBind(&objB); errB == nil {
c.String(http.StatusOK, `the body should be formB`)
} else {
...
}
}
```
同样，你能使用`c.ShouldBindBodyWith`
```
func SomeHandler(c *gin.Context) {
objA := formA{}
objB := formB{}
// This reads c.Request.Body and stores the result into the context.
if errA := c.ShouldBindBodyWith(&objA, binding.JSON); errA == nil {
c.String(http.StatusOK, `the body should be formA`)
// At this time, it reuses body stored in the context.
} else if errB := c.ShouldBindBodyWith(&objB, binding.JSON); errB == nil {
c.String(http.StatusOK, `the body should be formB JSON`)
// And it can accepts other formats
} else if errB2 := c.ShouldBindBodyWith(&objB, binding.XML); errB2 == nil {
c.String(http.StatusOK, `the body should be formB XML`)
} else {
...
}
}
```
- `c.ShouldBindBodyWith` 在绑定之前将body存储到上下文中，这对性能有轻微影响，因此如果你要立即调用，则不应使用此方法
- 此功能仅适用于这些格式 -- `JSON`, `XML`, `MsgPack`, `ProtoBuf`。对于其他格式，`Query`, `Form`, `FormPost`, `FormMultipart`, 可以被`c.ShouldBind()`多次调用而不影响性能（参考 [#1341](https://github.com/gin-gonic/gin/pull/1341)）
';