golang自定义数据类型查询与插入postgresql中point数据

具体代码如下：

package main

import (
    "bytes"
    "database/sql"
    "database/sql/driver"
    "fmt"
    _ "github.com/lib/pq"
    "strconv"
    "strings"
)

// 自定义支持类型
type Point struct {
    X float64 `json:"lat"`
    Y float64 `json:"lng"`
}
// 实现driver.Valuer接口
func (p *Point) Value() (driver.Value,error) {
    buf := new(bytes.Buffer)
    fmt.Fprintf(buf,"(%f %f)",p.X,p.Y)
    return buf.Bytes(),nil
}

func (p *Point) String() string {
    return fmt.Sprintf("(%v %v)",p.Y)
}
// 实现sql.Scanner接口
func (p *Point) Scan(val interface{}) (err error) {
    if bb,ok := val.([]uint8); ok {
        tmp := bb[1 : len(bb)-1]
        coors := strings.Split(string(tmp[:]),",")
        if p.X,err = strconv.ParseFloat(coors[0], 64); err != nil {
            return err
        }
        if p.Y,err = strconv.ParseFloat(coors[1], 64); err != nil {
            return err
        }
    }
    return nil
}

type Agent struct {
    Id         int    `json:"id"`
    Name       string `json:"name"`
    Code       string `json:"code"`
    CS_NO      string `json:"cs_no"`
    Channel_id int    `json:"channel_id"`
    Address    string `json:"address"`
    Coordinate *Point `json:"point"`
}

func main() {
    pgurl := fmt.Sprintf("postgres://%s:%s@%s:%s/%s?sslmode=disable","postgres","123456","localhost","5432","people")

    db,err := sql.Open("postgres",pgurl)
    if err != nil {
        panic(fmt.Errorf("连接数据库出错:%v",err))
    }

    querysql := `SELECT * FROM t_agent`
    rows,err := db.Query(querysql)
    if err != nil {
        panic(fmt.Errorf("查询数据出错:%v",err))
    }

    for rows.Next() {
        agent := &Agent{Coordinate: &Point{}}
        err = rows.Scan(&agent.Id,&agent.Name,&agent.Code,&agent.CS_NO,&agent.Channel_id,&agent.Address,agent.Coordinate)
        fmt.Println(agent,err)
    }
    var id int
    err = db.QueryRow("INSERT INTO t_agent (name,code,cs_no,address,coordinate) VALUES($1,$2,$3,$4,$5) RETURNING id","test1","123457","2","111","(12,43)").Scan(&id)

    fmt.Println("id:",id,"err:",err)
}

字段类型需要支持查询的scan时，需要实现sql.Scanner接口 字段类型需要支持插入时，需要实现driver.Valuer接口