英文:
golang can't write to text file: the handle is invalid
问题
大家好，
我很抱歉这么快又提出一个问题，但最近在使用Go语言时总是一个接一个的问题。
我有一个工作中的网页爬虫（多亏了大家的帮助），可以从这个维基页面上获取我想要的所有信息：http://monsterhunter.wikia.com/wiki/MH4U:_Item_List
它可以显示我想要的所有内容，没有问题。然而，当我尝试写入一个.txt文件时，出现了一个错误，错误信息是："0 write mh4u.txt: The handle is invalid"。
以下是我目前的代码供参考：
package main
import (
"fmt"
"log"
"github.com/PuerkitoBio/goquery"
"os"
"io"
)
func main() {
filename := "mh4u.txt"
file, err := os.Create(filename)
if err!= nil {
fmt.Println(err)
}
doc, err := goquery.NewDocument("http://www.ign.com/wikis/monster-hunter-4/Items")
if err != nil {
log.Fatal(err)
}
doc.Find("tbody").Each(func(i int, s *goquery.Selection) {
s.Find("td").Each(func(j int, s2 *goquery.Selection) {
if s3 := s2.Find("img"); s3 != nil && s3.Length() > 0 {
return
}
fmt.Printf(s2.Text())
n, err := io.WriteString(file, s2.Text())
if err != nil {
fmt.Println(n, err)
}
})
file.Close()
})
}
通过测试其他网站，我认为可能有一些隐藏字符导致写入操作出现问题，但这只是我猜测的原因。
非常感谢您提供的任何建议/提示/解决方案！
英文:
Hello again everybody,
I apologize for asking another question so soon, but it just seems to be one thing after another with Go lately.
I have a working web page scraper (thanks to everybody's help) that grabs all the info I want from this wiki page: http://monsterhunter.wikia.com/wiki/MH4U:_Item_List
It then displays everything I want, no hiccups. However, when I go to write to a .txt file I get an error stating: "0 write mh4u.txt: The handle is invalid"
Here is my current code for reference:
package main
import (
"fmt"
"log"
"github.com/PuerkitoBio/goquery"
"os"
"io"
)
func main() {
filename := "mh4u.txt"
file, err := os.Create(filename)
if err!= nil {
fmt.Println(err)
}
doc, err := goquery.NewDocument("http://www.ign.com/wikis/monster-hunter-4/Items")
if err != nil {
log.Fatal(err)
}
doc.Find("tbody").Each(func(i int, s *goquery.Selection) {
s.Find("td").Each(func(j int, s2 *goquery.Selection) {
if s3 := s2.Find("img"); s3 != nil && s3.Length() > 0 {
return
}
fmt.Printf(s2.Text())
n, err := io.WriteString(file, s2.Text())
if err != nil {
fmt.Println(n, err)
}
})
file.Close()
})
}
Testing this code with other web sites leads me to believe that there is maybe some hidden characters that is giving the writer some issues, but that's the only thing I can guess.
Thanks so much for any suggestions/tips/solutions you can offer!
答案1
得分: 6
你正在闭包内调用file.Close()。如果doc.Find("tbody").Each被多次调用，你将尝试向已关闭的文件写入。你应该在创建文件后立即延迟关闭文件：
file, err := os.Create(filename)
if err != nil {
log.Fatal(err)
}
defer file.Close()
英文:
You're calling file.Close() inside a closure. If doc.Find("tbody").Each is called more than one time, you'll end up trying to write to a closed file. You should defer the file closing right after you've created it:
file, err := os.Create(filename)
if err != nil {
log.Fatal(err)
}
defer file.Close()
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