golang如何操作csv文件详解

package main
 
import (
    "bufio"
    "encoding/json"
    "errors"
    "flag"
    "fmt"
    "io"
    "os"
    "strconv"
    "strings"
 
    "github.com/axgle/mahonia"
)
 
//给 fmt.Println 起一个短的别名。
var p = fmt.Println
 
//定义一个全局变量 一个月上班加休息总天数
var gAllDays float64 = 0
 
//定义一个全局变量 考勤异常的天数
var gAbnormalDays int = 0
 
//上班信息
type WorkInfo struct {
    WorkDate  string //上班日期
    StartTime string //上班打卡时间
    EndTime   string //下班打卡时间
    LaborHour string //当天工时
}
 
//考勤异常信息
type WorkAbnormalInfo struct {
    WorkDate   string //上班日期
    NormalInfo string //异常信息
}
 
/**
 * @brief  把当前字符串按照指定方式进行编码
 * @param[in]       src                   待进行转码的字符串
 * @param[in]       srcCode               字符串当前编码
 * @param[in]       tagCode               要转换的编码
 * @return   进行转换后的字符串
 */
func ConvertToString(src string, srcCode string, tagCode string) (string, error) {
    if len(src) == 0 || len(srcCode) == 0 || len(tagCode) == 0 {
        return "", errors.New("input arguments error")
    }
    srcCoder := mahonia.NewDecoder(srcCode)
    srcResult := srcCoder.ConvertString(src)
    tagCoder := mahonia.NewDecoder(tagCode)
    _, cdata, _ := tagCoder.Translate([]byte(srcResult), true)
    result := string(cdata)
 
    return result, nil
}
 
/**
 * @brief            写入数据到指定名字的文件中
 * @param[in]       buf                    待写入的数据内容
 * @param[in]       name                文件名字
 * @return   成功返回nil 失败返回error    错误信息
 */
func WriteFile(name string, buf string) error {
    if len(name) == 0 || len(buf) == 0 {
        return errors.New("input arguments error")
    }
 
    fout, err := os.OpenFile(name, os.O_CREATE|os.O_RDWR, 0666)
    defer fout.Close()
    if err != nil {
        return err
    }
 
    //写入到本地文件中
    fout.WriteString(buf)
 
    return nil
}
 
/**
 * @brief  读取文件
 * @param[in]       name            文件名（可以加路径）
 * @return   成功返回 文件内容，失败返回error    错误信息
 */
func ReadFile(name string) ([]byte, error) {
    if len(name) == 0 {
        return nil, errors.New("input arguments error")
    }
 
    //打开本地文件 读取出全部数据
    fin, err := os.Open(name)
    defer fin.Close()
    if err != nil {
        return nil, errors.New("Close error")
    }
 
    buf_len, _ := fin.Seek(0, os.SEEK_END)
    fin.Seek(0, os.SEEK_SET)
 
    buf := make([]byte, buf_len)
    fin.Read(buf)
 
    return buf, nil
}
 
/**
 * @brief  读取csv文件并打印指定员工信息
 * @param[in]       csvName            csv文件名（可以加路径）
 * @param[in]       employeeName        员工名字
 * @return   成功返回 员工结构体信息，失败返回error    错误信息
 */
func ReadCsvFile(csvName string, employeeName string) ([]WorkInfo, error) {
    if len(csvName) == 0 || len(employeeName) == 0 {
        return nil, errors.New("error: input arguments error")
    }
 
    var WorkInfoSet []WorkInfo
    var AbnormalSet []WorkAbnormalInfo
    var isExistName bool
    var dayCount float64 = 0
    var isNormal string
    var isNormalFlag bool
 
    var index int = 0
    var indexWorkDate int
    var indexStartTime int
    var indexEndTime int
    var indexLaborHour int
    var indexNormalInfo int
    var indexIsNormal int
 
    var i int = 0
 
    f, err := os.Open(csvName)
    if err != nil {
        return nil, err
    }
    defer f.Close()
 
    rd := bufio.NewReader(f)
    for {
        gbk_line, err := rd.ReadString('\n') //以'\n'为结束符读入一行
        if err != nil || io.EOF == err {
            break
        }
        //p("gbk:", gbk_line)
 
        //把每一行gbk格式的字符串 转换为 utf-8格式字符串
        utf8_line, _ := ConvertToString(gbk_line, "gbk", "utf-8")
 
        //对第一行进行处理
        if i == 0 {
            i = 1 //保证 只有第一行被处理
            p("utf8:", utf8_line)
            first_line := strings.Split(utf8_line, ",")
 
            for _, val := range first_line {
 
                if val == "日期" {
                    indexWorkDate = index
                }
                if val == "上班" {
                    indexStartTime = index
                }
                if val == "下班" {
                    indexEndTime = index
                }
                if val == "工时" {
                    indexLaborHour = index
                }
                if val == "是否有考勤异常" {
                    indexIsNormal = index
                }
                if val == "工时异常" {
                    indexNormalInfo = index
                }
 
                index++
            }
        }
 
        if strings.Contains(utf8_line, employeeName) {
            //把存在员工标记为true
            isExistName = true
 
            split_line := strings.Split(utf8_line, ",")
            person_temp := WorkInfo{split_line[indexWorkDate],
                split_line[indexStartTime],
                split_line[indexEndTime],
                split_line[indexLaborHour],
            }
 
            //考勤表天数加1
            dayCount++
            isNormal = split_line[indexIsNormal]
            //统计打卡异常的信息
            if isNormal == "是" {
                aInfo := WorkAbnormalInfo{split_line[indexWorkDate], split_line[indexNormalInfo]}
                AbnormalSet = append(AbnormalSet, aInfo)
 
                gAbnormalDays++
                isNormalFlag = true
            }
 
            WorkInfoSet = append(WorkInfoSet, person_temp)
        }
    }
 
    //统计考勤表里所有天数
    gAllDays = dayCount
    //对于不存在指定员工名字 的处理
    if !isExistName {
        p("\nRemind: There is no employee is csv file!\n")
        os.Exit(1)
    }
 
    //显示员工所有考勤信息
    p("\n员工姓名：", employeeName)
    p("\n全部考勤信息：")
    for _, temp := range WorkInfoSet {
        fmt.Printf(
            "日期:%s ,上班:%s,下班:%s,工时:%s\n",
            temp.WorkDate,
            temp.StartTime,
            temp.EndTime,
            temp.LaborHour,
        )
    }
 
    //显示员工打卡异常信息
    if isNormalFlag {
        p("\n异常考勤信息：")
        for _, val := range AbnormalSet {
            fmt.Printf("日期:%s , 异常信息:%s\n", val.WorkDate, val.NormalInfo)
        }
        p("温馨提示：考勤出现异常信息，请及时给助理说明情况～_～\n")
    }
 
    return WorkInfoSet, nil
}
 
/**
* @brief  写入json文件
* @param[in]       employeeName        员工名字
* @param[in]       workInfoSet            员工结构体信息
* @return   成功返回 nil，失败返回error    错误信息
 */
func WriteJsonFile(employeeName string, workInfoSet []WorkInfo) error {
    if len(employeeName) == 0 || workInfoSet == nil {
        return errors.New("error: input arguments error")
    }
 
    //把输出内容写入name.json文件中
    filename := fmt.Sprintf("%s%s", employeeName, ".json")
    str, _ := json.Marshal(workInfoSet)
    err := WriteFile(string(str), filename)
    if err != nil {
        return err
    }
    return nil
}
 
/**
* @brief  读取json文件
* @param[in]       employeeName        员工名字
* @return   成功返回 nil，失败返回error    错误信息
 */
func ReadJsonFile(employeeName string) error {
    if len(employeeName) == 0 {
        return errors.New("error: input arguments error")
    }
 
    var WorkInfoSet []WorkInfo
    filename := fmt.Sprintf("%s%s", employeeName, ".json")
 
    ReadJsonBuf, err := ReadFile(filename)
    if err != nil {
        p(err.Error())
        return err
    }
    var sumHour float64 = 0.0
    var dayCount float64 = 0
    var weekCounts float64 = 0.0
    var averageWeekHour float64 = 0.0
 
    json.Unmarshal(ReadJsonBuf, &WorkInfoSet)
 
    for _, one_work := range WorkInfoSet {
 
        //去掉打卡异常情况和周六末情况 (如果周六末加班 数据依然计算进入总工时)
        if one_work.StartTime == "" || one_work.EndTime == "" {
            continue
        }
 
        one_day_hour, _ := strconv.ParseFloat(one_work.LaborHour, 64)
        sumHour += one_day_hour
        dayCount++
    }
 
    fmt.Printf("根据json文件计算工时，考勤正常天数：%2.0f, 异常天数：%d\n", dayCount, gAbnormalDays)
    weekCounts = gAllDays / 7
    averageWeekHour = sumHour / weekCounts
    //p("考勤表总天数：", gAllDays, ",共多少周：", week_counts)
 
    fmt.Printf("月总工时：%.4f 每周的平均工时:%.4f\n\n", sumHour, averageWeekHour)
 
    return nil
}
 
func main() {
    args := os.Args
 
    input := flag.String("i", "查无此人", "input employee name")
    path := flag.String("p", "./data.csv", "input csv file path")
 
    flag.Parse()
 
    if len(args) == 1 {
        fmt.Println("./main: missing operand")
        fmt.Println("Try `./main -h' or './main --help' for more information.")
        return
    }
 
    var csvName string = *path
    var employeeName string = *input
 
    //读取csv文件并打印指定员工信息
    WorkInfoSet, err := ReadCsvFile(csvName, employeeName)
    if err != nil {
        p(err.Error())
        return
    }
 
    //把指定员工信息写入json文件
    err = WriteJsonFile(employeeName, WorkInfoSet)
    if err != nil {
        p(err.Error())
        return
    }
 
    //读取json文件并计算指定员工总工时和平均工时
    err = ReadJsonFile(employeeName)
    if err != nil {
        p(err.Error())
        return
    }
}

func main() {
	f, err := os.Create("data.csv")
	if err != nil {
		panic(err)
	}
	defer f.Close()

	f.WriteString("\xEF\xBB\xBF") // 写入UTF-8 BOM，避免使用Microsoft Excel打开乱码

	writer := csv.NewWriter(f)
	writer.Write([]string{"编号", "姓名", "年龄"})
	writer.Write([]string{"1", "张三", "23"})
	writer.Write([]string{"2", "李四", "24"})
	writer.Write([]string{"3", "王五", "25"})
	writer.Write([]string{"4", "赵六", "26"})
	writer.Flush() // 此时才会将缓冲区数据写入
}

func ExportCsv(c *gin.Context) {
	bytesBuffer := &bytes.Buffer{}
	bytesBuffer.WriteString("\xEF\xBB\xBF") // 写入UTF-8 BOM，避免使用Microsoft Excel打开乱码

	writer := csv.NewWriter(bytesBuffer)
	writer.Write([]string{"编号", "姓名", "年龄"})
	writer.Write([]string{"1", "张三", "23"})
	writer.Write([]string{"2", "李四", "24"})
	writer.Write([]string{"3", "王五", "25"})
	writer.Write([]string{"4", "赵六", "26"})

	writer.Flush() // 此时才会将缓冲区数据写入

	// 设置下载的文件名
	c.Writer.Header().Set("Content-Disposition", "attachment;filename=data.csv")
	// 设置文件类型以及输出数据
	c.Data(http.StatusOK, "text/csv", bytesBuffer.Bytes())
	return
}