func readFileByRead(fileName string) {
    //打开和关闭文件
    file, err := os.Open(fileName)
    if err != nil {
        fmt.Println("Open file failed! err:", err)
        return
    }
    defer file.Close()

    //读取文件
    var content []byte
    var tmp = make([]byte, 128)
    for {
        n, err := file.Read(tmp)
        if err == io.EOF {
            fmt.Println("Read Done!")
            break
        }
        if err != nil {
            fmt.Println("Read file failed, err:", err)
            return
        }
        content = append(content, tmp[:n]...)
    }
    fmt.Println(string(content))
}

// bufio按行读取示例
func readFileByBufio(fileName string) {
    //打开和关闭文件
    file, err := os.Open(fileName)
    if err != nil {
        fmt.Println("Open file failed! err:", err)
        return
    }
    defer file.Close()

  //读取文件
    reader := bufio.NewReader(file)
    for {
        line, err := reader.ReadString('\n')
        if err == io.EOF {
            if len(line) != 0 {
                fmt.Println(line)
            }
            fmt.Println("Read Done")
            break
        }
        if err != nil {
            fmt.Println("Read file failed, err:", err)
            return
        }
        fmt.Println(line)
    }

}

func readFileByIoutil(fileName string) {
    content, err := ioutil.ReadFile(fileName)
    if err != nil {
        fmt.Println("Read file failed,err:", err)
        return
    }
    fmt.Println(string(content))
}

func writeFileByWrite(content string) {
    // 打开文件
    file, err := os.OpenFile("robin.txt", os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0666)
    if err != nil {
        fmt.Println("Open file failed, err: ", err)
        return
    }
    defer file.Close()
    
    //写入内容
    file.Write([]byte(content)) //通过字节切片写入
    file.WriteString(content)   //通过字符串写入
}

func writeFileByBufio(content string) {
    //打开文件
    file, err := os.OpenFile("robin.txt", os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0666)
    if err != nil {
        fmt.Println("Open file failed, err: ", err)
        return
    }
    defer file.Close()

    //写入内容
    writer := bufio.NewWriter(file)
    for i := 0; i < 10; i++ {
        writer.WriteString(content) //将数据先写入缓存
    }
    writer.Flush()
}

func writeFileByIoutil(content string) {
    for i := 0; i < 10; i++ {
        err := ioutil.WriteFile("robin.txt", []byte(content), 0666)
        if err != nil {
            fmt.Println("write file failed, err:", err)
            return
        }
    }
}

func readFileByRead(fileName string) {
    //打开和关闭文件
    file, err := os.Open(fileName)
    if err != nil {
        fmt.Println("Open file failed! err:", err)
        return
    }
    defer file.Close()

    //读取文件
    var content []byte
    var tmp = make([]byte, 128)
    for {
        n, err := file.Read(tmp)
        if err == io.EOF {
            fmt.Println("Read Done!")
            break
        }
        if err != nil {
            fmt.Println("Read file failed, err:", err)
            return
        }
        content = append(content, tmp[:n]...)
    }
    fmt.Println(string(content))
}

// bufio按行读取示例
func readFileByBufio(fileName string) {
    //打开和关闭文件
    file, err := os.Open(fileName)
    if err != nil {
        fmt.Println("Open file failed! err:", err)
        return
    }
    defer file.Close()

  //读取文件
    reader := bufio.NewReader(file)
    for {
        line, err := reader.ReadString('\n')
        if err == io.EOF {
            if len(line) != 0 {
                fmt.Println(line)
            }
            fmt.Println("Read Done")
            break
        }
        if err != nil {
            fmt.Println("Read file failed, err:", err)
            return
        }
        fmt.Println(line)
    }

}

func readFileByIoutil(fileName string) {
    content, err := ioutil.ReadFile(fileName)
    if err != nil {
        fmt.Println("Read file failed,err:", err)
        return
    }
    fmt.Println(string(content))
}

func writeFileByWrite(content string) {
    // 打开文件
    file, err := os.OpenFile("robin.txt", os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0666)
    if err != nil {
        fmt.Println("Open file failed, err: ", err)
        return
    }
    defer file.Close()
    
    //写入内容
    file.Write([]byte(content)) //通过字节切片写入
    file.WriteString(content)   //通过字符串写入
}

func writeFileByBufio(content string) {
    //打开文件
    file, err := os.OpenFile("robin.txt", os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0666)
    if err != nil {
        fmt.Println("Open file failed, err: ", err)
        return
    }
    defer file.Close()

    //写入内容
    writer := bufio.NewWriter(file)
    for i := 0; i < 10; i++ {
        writer.WriteString(content) //将数据先写入缓存
    }
    writer.Flush()
}

func writeFileByIoutil(content string) {
    for i := 0; i < 10; i++ {
        err := ioutil.WriteFile("robin.txt", []byte(content), 0666)
        if err != nil {
            fmt.Println("write file failed, err:", err)
            return
        }
    }
}