#yyds干货盘点#golang实现通过mysql语句实现分页查询

Posted 2022-03-24 峰啊疯了

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1.前端接口调用

#yyds干货盘点#golang实现通过mysql语句实现分页查询_数据库分页

2.register访问入口

//查询一个用户下所有的subnet
    ws.Route(ws.GET("/subnets").
        To(sc.ListSubnet).
        Doc("List subnets authorized to the login user.").
        Param(ws.QueryParameter(query.ParameterPage, "page").Required(false).DataFormat("page=%d").DefaultValue("page=1")).
        Param(ws.QueryParameter(query.ParameterLimit, "limit").Required(false)).
        Returns(http.StatusOK, api.StatusOK, api.ListResult))

3.解析参数

//查询某个用户下所有的subnet信息
func (v *SubController) ListSubnet(request *restful.Request, response *restful.Response) 
    username := request.Attribute(filters.UserName).(string)

    subnetService := &service.SubnetService
    query := query.ParseQueryParameter(request)
    result, err := subnetService.ListSubnet(query, v.Db, username)
    if err != nil 
        api.HandleError(response, request, err)
        return
    
    response.WriteEntity(result)

#yyds干货盘点#golang实现通过mysql语句实现分页查询_数据库分页_02

4.service实现

//查询一个用户所有的subnet信息
func (ss *SubnetService) ListSubnet(query *query.Query, db *sql.DB, userName string) (*api.ListResult, error) 
    sm := mapper.NewSubnetMapper(db)
    sb, err := sm.SearchAllByUserName(query, userName)
    return sb, err

5.mapper实现

//查询用户下的所以信息
func (s *SubnetMapper) SearchAllByUserName(query *query.Query, userName string) (*api.ListResult, error) 

    totalRow, err := s.Db.Query("SELECT COUNT(*) from t_subnet ,t_vpc where t_vpc.id = t_subnet.vpcid and username = ?", userName)
    if err != nil 
        klog.Error("query orders count error", err)
        return nil, err
    
    total := 0
    for totalRow.Next() 
        err := totalRow.Scan(
            &total,
        )
        if err != nil 
            klog.Error("query orders count error", err)
            continue
        
    
    totalRow.Close()

    rows, err := s.Db.Query(SearchAllByUserNameSql, userName, query.Pagination.Limit, query.Pagination.Offset)
    defer func() 
        if rows != nil 
            rows.Close()
        
    ()
    if err != nil 
        klog.Error("query subnet error", err)
        return nil, err
    
    items := make([]interface, 0)
    for rows.Next() 
        ss := new(vpc.SubnetItem)
        err = rows.Scan(&ss.VpcName, &ss.VpcNetwork, &ss.SubnetName, &ss.SubnetNetwork, &ss.CreateTime)
        items = append(items, *ss)
    
    return &api.ListResult
        TotalItems: total,
        Items:      items,
    , nil