通过将指向目标片的指针作为参数传递，可以避免在调用函数中使用类型Assert。下面是经过修改的rowstostructs：

// RowsToStructs scans rows to the slice pointed to by dest.
// The slice elements must be pointers to structs with exported
// fields corresponding to the the columns in the result set.
//
// The function panics if dest is not as described above.
func RowsToStructs(rows *sql.Rows, dest interface{}) error {

    // 1. Create a slice of structs from the passed struct type of model
    //
    // Not needed, the caller passes pointer to destination slice.
    // Elem() dereferences the pointer.
    //
    // If you do need to create the slice in this function
    // instead of using the argument, then use
    // destv := reflect.MakeSlice(reflect.TypeOf(model).

    destv := reflect.ValueOf(dest).Elem()

    // Allocate argument slice once before the loop.

    args := make([]interface{}, destv.Type().Elem().NumField())

    // 2. Loop through each row

    for rows.Next() {

        // 3. Create a struct of passed mode interface{} type
        rowp := reflect.New(destv.Type().Elem())
        rowv := rowp.Elem()

        // 4. Scan the row results to a slice of interface{}
        // 5. Set the field values of struct created in step 3 using the slice in step 4
        //
        // Scan directly to the struct fields so the database
        // package handles the conversion from database
        // types to a Go types.
        //
        // The slice args is filled with pointers to struct fields.

        for i := 0; i < rowv.NumField(); i++ {
            args[i] = rowv.Field(i).Addr().Interface()
        }

        if err := rows.Scan(args...); err != nil {
            return err
        }

        // 6. Add the struct created in step 3 to slice created in step 1

        destv.Set(reflect.Append(destv, rowv))

    }
    return nil
}

这样称呼：

func (m *ContractModel) Documents(cid int) ([]*models.Document, error) {
    results, err := m.DB.Query(queries.DOCUMENTS, cid)
    if err != nil {
        return nil, err
    }
    defer results.Close()
    var documents []*models.Document
    err := RowsToStruct(results, &documents)
    return documents, err
}

通过将查询移动到助手函数来消除更多样板文件：

func QueryToStructs(dest interface{}, db *sql.DB, q string, args ...interface{}) error {
    rows, err := db.Query(q, args...)
    if err != nil {
        return err
    }
    defer rows.Close()
    return RowsToStructs(rows, dest)
}

这样称呼：

func (m *ContractModel) Documents(cid int) ([]*models.Document, error) {
    var documents []*model.Document
    err := QueryToStructs(&documents, m.DB, queries.DOCUMENTS, cid)
    return documents, err
}

"... 但是reflect包无法从传递的接口{}类型创建结构片？

func sliceFromElemValue(v interface{}) (interface{}) {
    rt := reflect.TypeOf(v)
    rs := reflect.MakeSlice(reflect.SliceOf(rt), 0, 0)

    for i := 0; i < 3; i++ { // dummy loop
        rs = reflect.Append(rs, reflect.New(rt).Elem())
    }

    return rs.Interface()
}

https://play.golang.com/p/o4aj-f71egw
“我要达到的目标如下”

func RowsToStructs(rows *sql.Rows, model interface{}) ([]interface{}, error) { ...

或者你在找这个？

func sliceFromElemValue(v interface{}) ([]interface{}) {
    rt := reflect.TypeOf(v)
    s := []interface{}{}

    for i := 0; i < 3; i++ { // dummy loop
        s = append(s, reflect.New(rt).Elem().Interface())
    }

    return s
}

https://play.golang.com/p/i57z8oo8n7g