Go寫文件實例

在Go中寫入文件與讀取文件的模式類似。首先我們來看一些讀取文件的例子。寫入文件需要檢查大多數調用錯誤。

所有的示例代碼，都放在 F:\worksp\golang 目錄下。安裝Go編程環境請參考：http://www.yiibai.com/go/go\_environment.html

writing-files.go的完整代碼如下所示 -

package main

import (
    "bufio"
    "fmt"
    "io/ioutil"
    "os"
)

func check(e error) {
    if e != nil {
        panic(e)
    }
}

func main() {

    // To start, here's how to dump a string (or just
    // bytes) into a file.
    d1 := []byte("hello\ngo\n")
    err := ioutil.WriteFile("dat1.txt", d1, 0644)
    check(err)

    // For more granular writes, open a file for writing.
    f, err := os.Create("dat2.txt")
    check(err)

    // It's idiomatic to defer a `Close` immediately
    // after opening a file.
    defer f.Close()

    // You can `Write` byte slices as you'd expect.
    d2 := []byte{115, 111, 109, 101, 10}
    n2, err := f.Write(d2)
    check(err)
    fmt.Printf("wrote %d bytes\n", n2)

    // A `WriteString` is also available.
    n3, err := f.WriteString("writes\n")
    fmt.Printf("wrote %d bytes\n", n3)

    // Issue a `Sync` to flush writes to stable storage.
    f.Sync()

    // `bufio` provides buffered writers in addition
    // to the buffered readers we saw earlier.
    w := bufio.NewWriter(f)
    n4, err := w.WriteString("buffered\n")
    fmt.Printf("wrote %d bytes\n", n4)

    // Use `Flush` to ensure all buffered operations have
    // been applied to the underlying writer.
    w.Flush()

}

執行上面代碼，將得到以下輸出結果 -

F:\worksp\golang>go run writing-files.go
wrote 5 bytes
wrote 7 bytes
wrote 9 bytes