optimize: file unexist error for binding

pkg/app/server/binding/internal/decoder/multipart_file_decoder.go

@@ -18,6 +18,7 @@ package decoder
 
 import (
 	"fmt"
+	"github.com/cloudwego/hertz/pkg/common/hlog"
 	"reflect"
 
 	"github.com/cloudwego/hertz/pkg/protocol"
@@ -52,7 +53,8 @@ func (d *fileTypeDecoder) Decode(req *protocol.Request, params param.Params, req
 	}
 	file, err := req.FormFile(fileName)
 	if err != nil {
-		return fmt.Errorf("can not get file '%s', err: %v", fileName, err)
+		hlog.Warnf("can not get file '%s', err: %v. so skip", fileName, err)
+		return nil
 	}
 	if field.Kind() == reflect.Ptr {
 		t := field.Type()
@@ -105,11 +107,13 @@ func (d *fileTypeDecoder) fileSliceDecode(req *protocol.Request, params param.Pa
 	}
 	multipartForm, err := req.MultipartForm()
 	if err != nil {
-		return fmt.Errorf("can not get multipartForm info, err: %v", err)
+		hlog.Warnf("can not get MultipartForm, err: %v. so skip", fileName, err)
+		return nil
 	}
 	files, exist := multipartForm.File[fileName]
 	if !exist {
-		return fmt.Errorf("the file '%s' is not existed", fileName)
+		hlog.Warnf("the file '%s' is not existed, so skip", fileName)
+		return nil
 	}
 
 	if field.Kind() == reflect.Array {