go module本地模块

//demo1\b1\b1s.go
package b1
import (
	"fmt"
	"demo666/a2"
)
func B1() {
	fmt.Println("B1")
	a2.A2()
}

//demo1\b1\b2s.go
package b1

import (
	"fmt"
)
func B2() {
	fmt.Println("B2")
}

//demo1\b1\b1inner\b2s.go
package b1i

import (
	"fmt"
)
func B1() {
	fmt.Println("b1inner")
}

//demo1\util\db.go
package dbpackage

import (
	"database/sql"
	"fmt"
	_ "github.com/lib/pq"
)
func Select(db *sql.DB) {
	rows, err := db.Query("SELECT * FROM users where id in (3,44,45,46,47,48,49)")
	CheckError(err)
	var es []Product
	for rows.Next() {
		var e Product
		rows.Scan(&e.ID, &e.nAMe, &e.Age)
		es = append(es, e)
	}
	fmt.Printf("%v", es)
}

*******************************

//demo1\a2\a2service.go
package a2

import (
    "fmt"
)

func A2() {
	fmt.Println("A2")
}

//demo1\go.mod
module demo666
go 1.19
require github.com/lib/pq v1.10.7

//demo1\a1.go
package main
import (
	"demo666/b1"
	"demo666/b1/b1inner"
	"demo666/util"
	"fmt"
)
func main() {
	fmt.Println("Starting")
	b1.B1()
	b1.B2()
	db1 := dbpackage.GetDB()
	defer db1.Close()
	dbpackage.Select(db1)
	b1i.B1()

}