Golang_小程序学golang

1 前置条件

Golang基本情况自行baidu/google

1.1 环境与工具

IDE：liteide (windows )、mingw-w64 (gcc)

DB：SQL Server 2008 R2

MQ: Kakfa

1.2 环境变量

Golang 需要将GOPATH添加到环境变量中

1.3 版本查看

Cmd中输入 go version 可以查看当前golang版本

2 示例程序功能简介

2.1 主功能

查询数据表A获取记录的消息编号MSG-Id.
从数据表B查询大于MSG-Id的100条连续数据.
将查询到的100条数据依次序列化成JSON数据，推送到消息队列Kafka中（供其它软件使用）.
100条推送成功后将最大的MSG-Id更新到数据表A.

2.2 辅助项

循环执行，每执行主功能一次，挂起2秒
记录关键日志到文件
从配置文件读取信息
在Console上显示实时信息

3 代码描述

3.1 目录结构与程序包

MainExe：主项目模块的目录

Domain领域层目录

xxDomain.go 领域层源码文件（Package yyDomain）

Model模型层目录

xxModel.go 模型层源码文件（Package yyModel）

Main.go:主函数源码文件，Package Main

Common：通用/公共功能模块目录

MQ_kafka帮助类子目录

Sarama.go: kafka帮助类源码（package KafkaHelper）

DB_SQLServer帮助类子目录

SQLServer.go: SQLServer帮助类源码（package SQLHelper）

File_CFG帮助类子目录

CFG.go: 配置文件操作帮助类源码（package CFGHelper）

在Goalng中源码的物理文件是按照目录（Directory）来管理, 每个*.go文件都存放在一个目录下，一个目录下的所有源文件只能属于相同的包package。在逻辑上，源码使用包（package）这种语法元素来组织源码，所有语法可见性均定义在package这个级别，每个*.go文件都属于一个Package。

程序调用: PackageName.xxxMethod/yyyFunction

3.2 源码文件SQLServer.go

这里用到了go-mssqldb这个包，在命令行cmd使用go get github.com/denisenkom/go-mssqldb 可以将程序包下载到本地

这个包在import时，前面加了横线，说明即使用【import _ 包路径】只是引用该包，仅仅是为了调用init()函数，所以无法通过包名来调用包中的其他函数。

package SQLHelper

import (

        "Common/File_CFG"

        "database/sql"

        "encoding/json"

        "fmt"

        "log"

        "time"

        _ "github.com/denisenkom/go-mssqldb"

)

func QueryDataReturnString(strSQL string /*, connInstance *sql.DB*/) (strValue string, err error) {

        ip, port, user, password, database, err := Base_ConfigFileHelper.GetSQLServerConfig()

        if err != nil {

               log.Fatal("Read Config File failed:", err.Error())

        }

        connString := fmt.Sprintf("server=%s;port%s;database=%s;user id=%s;password=%s", ip, port, database, user, password)

        connInstance, err := sql.Open("mssql", connString)

        if err != nil {

               log.Fatal("Open Connection failed:", err.Error())

        }

        defer connInstance.Close()

        var strLastId string

        errTemp := connInstance.QueryRow(strSQL).Scan(&strLastId)

        if errTemp != nil {

               log.Fatal("Query failed:", errTemp.Error())

        }

        return strLastId, errTemp

}

func QueryDataReturnArray(strSQL string /*, connInstance *sql.DB*/) (dataRows *sql.Rows) {

        ip, port, user, password, database, err := Base_ConfigFileHelper.GetSQLServerConfig()

        if err != nil {

               log.Fatal("Read Config File failed:", err.Error())

        }

        connString := fmt.Sprintf("server=%s;port%d;database=%s;user id=%s;password=%s", ip, port, database, user, password)

        // if isdebug {

        //      fmt.Println(connString)

        // }

        connInstance, err := sql.Open("mssql", connString)

        if err != nil {

               log.Fatal("Open Connection failed:", err.Error())

        }

        defer connInstance.Close()

        stmt, err := connInstance.Prepare(strSQL)

        if err != nil {

               log.Fatal("Prepare failed:", err.Error())

        }

        rowsArray, err := stmt.Query()

        if err != nil {

               log.Fatal("Query failed:", err.Error())

        }

        stmt.Close()

        //defer rowsArray.Close()

        return rowsArray

}

func ExeNoQuery(strSQL string /*, connInstance *sql.DB*/) (returnResult int64, err error) {

        ip, port, user, password, database, err := Base_ConfigFileHelper.GetSQLServerConfig()

        if err != nil {

               log.Fatal("Read Config File failed:", err.Error())

        }

        connString := fmt.Sprintf("server=%s;port%d;database=%s;user id=%s;password=%s", ip, port, database, user, password)

        connInstance, err := sql.Open("mssql", connString)

        if err != nil {

               log.Fatal("Open Connection failed:", err.Error())

        }

        defer connInstance.Close()

        stmt, err := connInstance.Prepare(strSQL)

        if err != nil {

               log.Fatal("Prepare failed:", err.Error())

        }

        defer stmt.Close()

        returnRows, err := stmt.Exec()

        if err != nil {

               log.Fatal("Query failed:", err.Error())

        }

        //我们可以获得插入的id

        //id, err := rs.LastInsertId()

        //可以获得影响行数

        result, err := returnRows.RowsAffected()

        return result, err

}

// 参考资料

//Go-SQLServer https://www.cnblogs.com/dfsxh/p/10207866.html

//Go-SQLServer https://www.cnblogs.com/Liang2790912648/p/10604310.html

//Go-SQLServer https://www.jianshu.com/p/136ac470fc17

//Go-SQLServer https://blog.csdn.net/chen_peng7/article/details/89317922

//GO-MySQL(scan) https://zhidao.baidu.com/question/1759806412743140028.html

3.3 源码文件Sarama.go

package KafkaHelper

import (

        "fmt"

        "time"

        "github.com/Shopify/sarama"

)

func CreateInstance() (syncClient sarama.SyncProducer, err error) {

        //初始化配置

        newConfig := sarama.NewConfig()

        newConfig.Producer.RequiredAcks = sarama.WaitForAll

        newConfig.Producer.Partitioner = sarama.NewRandomPartitioner

        newConfig.Producer.Return.Successes = true

        //生产者

        client, err := sarama.NewSyncProducer([]string{"172.16.77.53:9092"}, newConfig)

        if err != nil {

               fmt.Println("producer close,err:", err)

               return nil, err

        } else {

               return client, err

        }

}

func SendMessage(syncClient sarama.SyncProducer, InMessage string) {

        msg := &sarama.ProducerMessage{}

        msg.Topic = "02.dbo "

        msg.Value = sarama.StringEncoder(InMessage)

        //发送消息

        pid, offset, err := syncClient.SendMessage(msg)

        if err != nil {

               fmt.Println(time.Now().Format("2006-01-02 15:04:05")+" send failed: ", err)

        } else {

               fmt.Printf(time.Now().Format("2006-01-02 15:04:05")+" send   success:1      pid:%v offset:%v\n", pid, offset)

        }

}

因为在.net core 环境下用Confluent成功，本想goalng用Confluent package继续测试，但是下载这个包很困难（墙），所以放弃了。

// 参考资料

//Go-Kafka https://www.cnblogs.com/vincenshen/p/9824486.html

//Go-Kafka https://www.cnblogs.com/pyyu/p/8371649.html

//Go-Kafka https://blog.csdn.net/lanyang123456/article/details/78377152

//Go-Kafka https://www.jianshu.com/p/1136f37cc419

3.4 源码文件CFG.go

package CFGHelper

import (

        "fmt"

        "github.com/Unknwon/goconfig"

)

func GetSQLServerConfig() (ip string, port string, username string, password string, dbname string, err error) {

               cfgFile, err := goconfig.LoadConfigFile("conf.ini")

               if err != nil {

                               fmt.Println(err)

               }

               ipGet, err := cfgFile.GetValue("DB_SQLServer", "ip")

               if err != nil {

                               fmt.Println(err)

               }

               portGet, err := cfgFile.GetValue("DB_SQLServer", "port")

               if err != nil {

                               fmt.Println(err)

               }

               usernameGet, err := cfgFile.GetValue("DB_SQLServer", "username")

               if err != nil {

                              fmt.Println(err)

               }

               passwordGet, err := cfgFile.GetValue("DB_SQLServer", "password")

               if err != nil {

                               fmt.Println(err)

               }

               dbnameGet, err := cfgFile.GetValue("DB_SQLServer", "dbname")

               if err != nil {

                               fmt.Println(err)

               }

               return ipGet, portGet, usernameGet, passwordGet, dbnameGet, err

}

func GetKafkaConfig() (ip string, topic string, groupid string, err error) {

               cfgFile, err := goconfig.LoadConfigFile("../conf.ini")

               if err != nil {

                               fmt.Println(err)

               }

               ipGet, err := cfgFile.GetValue("MQ_Kafka", "ip")

               if err != nil {

                               fmt.Println(err)

               }

               topicGet, err := cfgFile.GetValue("MQ_Kafka", "topic")

               if err != nil {

                               fmt.Println(err)

               }

               groupidGet, err := cfgFile.GetValue("MQ_Kafka", "groupid")

               if err != nil {

                               fmt.Println(err)

               }

               return ipGet, topicGet, groupidGet, err

}

3.4 源码文件main.go

  import 里面有很多测试导入的包，如果报错就屏蔽掉

package main

import (

        "MainMenthod/Domain"

        "fmt"

        "io"

        "net/http"

        "os"

        "reflect"

        "time"

)

func main() {

        mainDomain.DoWork_Init()

        for true {

               //var currentMonth：=time.Now().String()

               mainDomain.DoWork_SendMSG()

               time.Sleep( * time.Second)

        }

        mainDomain.DoWork_Clean()

        //testReflect()

        //testgoroutine()

        //testhttpget()

        fmt.Println("program exit")

}

3.4 源码文件xxModel.go

package yyModel

type BrushCardModel struct {

        Odid      int32

        StepCode  string

        EmpCode   string

        SysCode   string

        Sort      string

        OrderCode string

        LoadDate  string

        WorkHours int32

}

3.4 源码文件yyDomain.go

package mainDomain

import (

        "CommonCode/DB_SQLServer"

        "CommonCode/MQ_Kafka"

        "MainMenthod/Model"

        "database/sql"

        "encoding/json"

        "fmt"

        "log"

        "os"

        "strconv"

        "strings"

        "time"

        "github.com/Shopify/sarama"

        _ "github.com/denisenkom/go-mssqldb"

)

var kafkaProducer sarama.SyncProducer

func DoWork_Init() {

        producer, err := KafkaHelper.CreateInstance()

        if err != nil {

               log.Fatal("Create Kafka Producer failed:", err.Error())

               fmt.Println("Create Kafka Producer failed" + err.Error())

               return

        } else {

               kafkaProducer = producer

        }

}

func DoWork_Clean() {

        kafkaProducer.Close()

}

func DoWork_SendMSG() {

        //固定的时间；“2006-01-02”

        file := "./" + time.Now().Format("") + ".txt"

        logFile, err := os.OpenFile(file, os.O_RDWR|os.O_CREATE|os.O_APPEND, os.ModePerm)

        if nil != err {

               panic(err)

        }

        defer logFile.Close()

        loger := log.New(logFile, "", log.Ldate|log.Ltime|log.Lshortfile)

        var strSQL_LastId string = "select LastMSGId from A where MSGTable='B'"

        LastMSGIdOfBC, err := SQLHelper.QueryDataReturnString(strSQL_LastId /*, connInstance*/)

        if err != nil {

               fmt.Println("Query LastMSGId  failed" + err.Error())

               loger.Output(, "Query LastMSGId  failed"+err.Error()+"\r\n")

        }

        var builderSQL strings.Builder

        builderSQL.WriteString(" select top 100 MaterialCardBrushID,Odid,SysCode,OrderCode,")

        builderSQL.WriteString(" EmpCode,StepCode,Sort,WorkHours, ")

        builderSQL.WriteString(" CONVERT(varchar(100), LoadDate, 20)    ")

        builderSQL.WriteString(" from B where MaterialCardBrushID >" + LastMSGIdOfBC)

        builderSQL.WriteString(" order by MaterialCardBrushID")

        //fmt.Println(builderSQL.String())

        var rowsArray *sql.Rows

        rowsArray = SQLHelper.QueryDataReturnArray(builderSQL.String() /*, connInstance*/)

        var materialCardBrushID int

        for rowsArray.Next() {

               ins_BrushCard := &mainModel.BrushCardModel{}

               err = rowsArray.Scan(&materialCardBrushID, &ins_BrushCard.Odid, &ins_BrushCard.SysCode, &ins_BrushCard.OrderCode,

                       &ins_BrushCard.EmpCode, &ins_BrushCard.StepCode, &ins_BrushCard.Sort, &ins_BrushCard.WorkHours,

                       &ins_BrushCard.LoadDate)

               if err != nil {

                       fmt.Println("Get Data from Row failed" + err.Error())

                       loger.Output(, "Get Data from Row failed"+err.Error()+"\r\n")

                       break

               } else {

                       jsonOfBrushCard, err := json.Marshal(ins_BrushCard)

                       if err != nil {

                               fmt.Println("生成json字符串错误" + err.Error())

                               loger.Output(, "生成json字符串错误"+err.Error()+"\r\n")

                       }

                       var strValue string = string(jsonOfBrushCard)

                       loger.Output(, strValue+"\r\n")

                       KafkaHelper.SendMessage(kafkaProducer, strValue)

               }

        }

        rowsArray.Close()

        var strSQL_Update string = "update SendLastMSGFlag set LastMSGId=" + strconv.Itoa(materialCardBrushID) + " where MSGTable='B'"

        result, err := SQLHelper.ExeNoQuery(strSQL_Update /*, connInstance*/)

        if err != nil {

               //log.Fatal("Update failed:materialCardBrushID="+strconv.Itoa(materialCardBrushID), err.Error())

               fmt.Println(time.Now().Format("2006-01-02 15:04:05") + " LastMSGId:" + strconv.Itoa(materialCardBrushID) + "  failed:" + err.Error())

               loger.Output(, " LastMSGId:"+strconv.Itoa(materialCardBrushID)+"        failed:"+err.Error()+"\r\n")

        } else {

                fmt.Println(time.Now().Format("2006-01-02 15:04:05") + " update success:" + strconv.FormatInt(result, ) + " LastMSGId:" + strconv.Itoa(materialCardBrushID))

               loger.Output(, " update success:"+strconv.FormatInt(result, )+"   LastMSGId:"+strconv.Itoa(materialCardBrushID)+"\r\n")

        }

}

// 参考资料

// Go-JSON https://www.cnblogs.com/pyyu/p/8309917.html

// Go-JSON https://www.jianshu.com/p/3534532e06ed

// Go-JSON https://studygolang.com/articles/8526 SQL结果集-JSON

// Go-base https://www.jianshu.com/p/dbb39c69e3f1 类型转换string、int、int64

// Go-base https://www.cnblogs.com/smallleiit/p/10694481.html 类型转换string、int、int64

// Go-base https://www.cnblogs.com/pyyu/p/8258133.html 自定义类型struct

// Go-base https://studygolang.com/articles/3383 log简介

3.4 配置文件conf.ini

[DB_SQLServer]

ip=127.0.0.1

port=

username=sa

password=

dbname=test

[MQ_Kafka]

ip=127.0.0.1:

topic=topcoco

groupid=zzc

对于熟悉一门编程语言，学习另外一种语言，总有一些困难：

首先是开始时的开发--编译-运行环境，也就是hello world，以及调试：需要搜集大量资料或教程才能敲门
其次是习惯，从面向过程转面向对象或者反之，都需要克服习惯
最后，是做一个工作上用到的，不大的有用的程序，除非你的兴趣特别强