golang实现分页算法

//分页方法，根据传递过来的页数，每页数，总数，返回分页的内容 7个页数 前 1，2，3，4，5 后 的格式返回,小于5页返回具体页数
func Paginator(page, prepage int, nums int64) map[string]interface{} {

    var firstpage int //前一页地址
    var lastpage int  //后一页地址
    //根据nums总数，和prepage每页数量 生成分页总数
    totalpages := int(math.Ceil(float64(nums) / float64(prepage))) //page总数
    if page > totalpages {
        page = totalpages
    }
    if page <= 0 {
        page = 1
    }
    var pages []int
    switch {
    case page >= totalpages-5 && totalpages > 5: //最后5页
        start := totalpages - 5 + 1
        firstpage = page - 1
        lastpage = int(math.Min(float64(totalpages), float64(page+1)))
        pages = make([]int, 5)
        for i, _ := range pages {
            pages[i] = start + i
        }
    case page >= 3 && totalpages > 5:
        start := page - 3 + 1
        pages = make([]int, 5)
        firstpage = page - 3
        for i, _ := range pages {
            pages[i] = start + i
        }
        firstpage = page - 1
        lastpage = page + 1
    default:
        pages = make([]int, int(math.Min(5, float64(totalpages))))
        for i, _ := range pages {
            pages[i] = i + 1
        }
        firstpage = int(math.Max(float64(1), float64(page-1)))
        lastpage = page + 1
        //fmt.Println(pages)
    }
    paginatorMap := make(map[string]interface{})
    paginatorMap["pages"] = pages
    paginatorMap["totalpages"] = totalpages
    paginatorMap["firstpage"] = firstpage
    paginatorMap["lastpage"] = lastpage
    paginatorMap["currpage"] = page
    return paginatorMap
}

测试结果如下

func main(){
    pageSize := 3 
    var rsCount int64 = 100
    currentPage := 8
    res := Paginator(currentPage,pageSize,rsCount)
    fmt.Println(res) 
}

运行结果如下

map[pages:[6 7 8 9 10] totalpages:34 firstpage:7 lastpage:9 currpage:8]