1、目的

        通过读取配置文件获取pgsql用户名和密码及数据库和数据表，从而读取所需字段值。

2、代码架构

      config/config.go:读取配置文件信息

      config/config.json:配置文件

      handle/handle.go:与pgsql数据库交互，获取所需数据

      main.go：主函数

3、代码展示

   config.go

package configimport ("io/ioutil""os""fmt""encoding/json"
)type Pgsql struct {//Pgsql账号Username string `json:"username"`//Pgsql密码Password string `json:"password"`//Pgsql地址Address string `json:"address"`//Pgsql端口Port int `json:"port"`//数据库名称Database string `json:"database"`//表名称Table string `json:"table"`//账号字段名称AccountField string `json:"accountField"`//密码字段名称PwdField string `json:"pwdField"`
}//配置文件路径
var ConfigPath string = "config/config.json"// pgsql配置信息缓存
var PgsqlData *Pgsqlfunc Init() {//初始化配置对象PgsqlData = new(Pgsql)//读取配置文件file, err := os.Open(ConfigPath)if err != nil {fmt.Println("config path:", err)os.Exit(1)}bytes, err := ioutil.ReadAll(file)if err != nil {fmt.Println("config file:", err)os.Exit(1)}//使用json转换至config对象中err = json.Unmarshal(bytes, PgsqlData)if err != nil {fmt.Println("json unmarshal:", err)os.Exit(1)}
}

    config.json

{"username": "***","password": "*********","address": "localhost","port": 5432,"database": "***","table": "***","accountField": "***","pwdField": "***"
}

  handle.go

package handleimport ("database/sql""errors""fmt""pgsql/config"_ "github.com/lib/pq"
)func Executl() error {config.Init()if config.PgsqlData != nil {//创建mysql连接db, err := sql.Open("postgres", fmt.Sprintf("host=%s port=%d user=%s password=%s dbname=%s sslmode=disable", config.PgsqlData.Address, config.PgsqlData.Port, config.PgsqlData.Username, config.PgsqlData.Password, config.PgsqlData.Database))if err != nil {return err}defer db.Close()str := fmt.Sprintf("select %s,%s from %s where NAME='%s'", config.PgsqlData.AccountField, config.PgsqlData.PwdField, config.PgsqlData.Table, config.PgsqlData.Username)rows := db.QueryRow(str)var name *sql.NullStringvar pwd *sql.NullStringerr = rows.Scan(&name, &pwd)if err != nil {return err}if name.String == "" || pwd.String == "" {return errors.New("data is null")}fmt.Println("name:",name.String)fmt.Println("passwd:",pwd.String)return nil}return errors.New("open config file failed")
}

  main.go

package mainimport ("pgsql/handle""os"
)func main() {err := handle.Executl()if err != nil {os.Exit(1)}
}