我正在嘗試在 Go 中為大型 xml 文件（ dblp.xml?）編寫一個非常簡單的解析器，其摘錄如下：<?xml version="1.0" encoding="ISO-8859-1"?><!DOCTYPE dblp SYSTEM "dblp.dtd"><dblp>? ? <article key="journals/cacm/Gentry10" mdate="2010-04-26">? ? ? ? <author>Craig Gentry</author>? ? ? ? <title>Computing arbitrary functions of encrypted data.</title>? ? ? ? <pages>97-105</pages>? ? ? ? <year>2010</year>? ? ? ? <volume>53</volume>? ? ? ? <journal>Commun. ACM</journal>? ? ? ? <number>3</number>? ? ? ? <ee>http://doi.acm.org/10.1145/1666420.1666444</ee>? ? ? ? <url>db/journals/cacm/cacm53.html#Gentry10</url>? ? </article>? ? <article key="journals/cacm/Gentry10" mdate="2010-04-26">? ? ? ? <author>Craig Gentry Number2</author>? ? ? ? <title>Computing arbitrary functions of encrypted data.</title>? ? ? ? <pages>97-105</pages>? ? ? ? <year>2010</year>? ? ? ? <volume>53</volume>? ? ? ? <journal>Commun. ACM</journal>? ? ? ? <number>3</number>? ? ? ? <ee>http://doi.acm.org/10.1145/1666420.1666444</ee>? ? ? ? <url>db/journals/cacm/cacm53.html#Gentry10</url>? ? </article></dblp>我的代碼如下，看起來好像在 發(fā)生了一些事情xml.Unmarshal(byteValue, &articles)，因為我無法在輸出中獲取任何 xml 的值。你能幫我解決我的代碼有什么問題嗎？
1 回答
青春有我
TA貢獻1784條經(jīng)驗 獲得超8個贊
您的代碼中有特定行返回錯誤
xml.Unmarshal(byteValue, &articles)
如果你把它改成
err = xml.Unmarshal(byteValue, &articles)
if err != nil {
fmt.Println(err.Error())
}
您會看到報告的錯誤：xml: encoding "ISO-8859-1" declared but Decoder.CharsetReader is nil。作為最佳實踐，您應(yīng)該始終檢查返回的錯誤。
要解決此問題，您可以從 XML 中刪除編碼屬性 ( encoding="ISO-8859-1") 或稍微更改解組代碼：
package main
import (
"encoding/xml"
"fmt"
"io"
"os"
"golang.org/x/text/encoding/charmap"
)
// Contains the array of articles in the dblp xml
type Dblp struct {
XMLName xml.Name `xml:"dblp"`
Dblp []Article `xml:"article"`
}
// Contains the article element tags and attributes
type Article struct {
XMLName xml.Name `xml:"article"`
Key string `xml:"key,attr"`
Year string `xml:"year"`
}
func main() {
xmlFile, err := os.Open("dblp.xml")
if err != nil {
fmt.Println(err)
}
fmt.Println("Successfully Opened TestDblp.xml")
// defer the closing of our xmlFile so that we can parse it later on
defer xmlFile.Close()
var articles Dblp
decoder := xml.NewDecoder(xmlFile)
decoder.CharsetReader = makeCharsetReader
err = decoder.Decode(&articles)
if err != nil {
fmt.Println(err)
}
for i := 0; i < len(articles.Dblp); i++ {
fmt.Println("Entered loop")
fmt.Println("get title: " + articles.Dblp[i].Key)
fmt.Println("get year: " + articles.Dblp[i].Year)
}
}
func makeCharsetReader(charset string, input io.Reader) (io.Reader, error) {
if charset == "ISO-8859-1" {
// Windows-1252 is a superset of ISO-8859-1, so should do here
return charmap.Windows1252.NewDecoder().Reader(input), nil
}
return nil, fmt.Errorf("Unknown charset: %s", charset)
}
運行上面的程序會導致：
Successfully Opened TestDblp.xml
Entered var
Entered loop
get title: journals/cacm/Gentry10
get year: 2010
Entered loop
get title: journals/cacm/Gentry10
get year: 2010
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