当查询的数据来自多个数据源，有哪些好的分页策略？

package main




import (

  "encoding/json"

  "fmt"

)




type User []struct {

  Name string `json:"name"`

  Age  string `json:"age"`

}




type Pagination struct {

  Total        int `json:"total"`

  CurrentPage  int `json:"currentPage"`

  PrePageCount int `json:"prePageCount"`

}




type ListPageData struct {

  List       User `json:"list"`

  Pagination Pagination `json:"pagination"`

}




func main() {

  jsonStr := `[{"name": "姓名1","age": "年龄1"},

      {"name": "姓名2","age": "年龄2"},

      {"name": "姓名3","age": "年龄3"},

      {"name": "姓名4","age": "年龄4"},

      {"name": "姓名5","age": "年龄5"},

      {"name": "姓名6","age": "年龄6"},

      {"name": "姓名7","age": "年龄7"},

      {"name": "姓名8","age": "年龄8"},

      {"name": "姓名9","age": "年龄9"},

      {"name": "姓名10","age": "年龄10"}

  ]`




  var user User

  err := json.Unmarshal([]byte(jsonStr), &user)

  if err != nil {

      fmt.Println(err.Error())

  }




  page := 2

  pageSize := 3

  pageData := ArraySlice(user, page, pageSize)




  listPageData := ListPageData{}

  listPageData.List = pageData

  listPageData.Pagination.Total = len(user)

  listPageData.Pagination.CurrentPage = page

  listPageData.Pagination.PrePageCount = pageSize




  jsonData, _ := JsonEncode(listPageData)

  fmt.Println(jsonData)

}




func JsonEncode(v interface{}) (string, error) {

  bytes, err := json.Marshal(v)

  if err != nil {

      return "", err

  }

  return string(bytes), nil

}




func ArraySlice(u User, page int, pageSize int) User {

  offset := (page - 1) * pageSize

  if offset > int(len(u)) {

      panic("offset: the offset is less than the length of s")

  }

  end := offset + pageSize

  if end < int(len(u)) {

      return u[offset:end]

  }

  return u[offset:]

}