如果字段为空，则避免XML整数解析错误

huangapple
go评论158阅读模式
英文:

Avoid XML integer parse errors if field empty

问题

考虑这两个XML文档

  1. <a>
  2.   <b nil="true"></b>
  3. </a>

和

  1. <a>
  2.   <b type="integer">1</b>
  3. </a>

如何在Go中正确地将此XML解组为类型为int的b结构字段，而不会在第一种情况下产生strconv.ParseInt: parsing "": invalid syntax错误？

在这种情况下，omitempty似乎不起作用。

示例：http://play.golang.org/p/fbhVJ4zUbl

英文:

Consider these 2 XML documents

  1. &lt;a&gt;
  2.   &lt;b nil=&quot;true&quot;&gt;&lt;/b&gt;
  3. &lt;/a&gt;

and

  1. &lt;a&gt;
  2.   &lt;b type=&quot;integer&quot;&gt;1&lt;/b&gt;
  3. &lt;/a&gt;

How can I unmarshal this XML properly in Go to a b struct field of type int, without producing a strconv.ParseInt: parsing &quot;&quot;: invalid syntax error in the first case?

omitempty doesn't seem to work in this case.

Example: http://play.golang.org/p/fbhVJ4zUbl

答案1

得分: 1

The omitempty tag is just respected with Marshal, not Unmarshal.

Unmarshal errors if the int value is not an actual int.

Instead, change B to a string. Then, convert B to an int with the strconv package. If it errors, set it to 0.

Try this snippet: http://play.golang.org/p/1zqmlmIQDB

英文:

The omitempty tag is just respected with Marshal, not Unmarshal.

Unmarshal errors if the int value is not an actual int.

Instead, change B to a string. Then, convert B to an int with the strconv package. If it errors, set it to 0.

Try this snippet: http://play.golang.org/p/1zqmlmIQDB

答案2

得分: 0

你可以使用"github.com/guregu/null"包。它有助于：

  1. package main
  2. import (
  3. "fmt"
  4.     "encoding/xml"
  5.     "github.com/guregu/null"
  6. )
  8. type Items struct{
  9.     It []Item `xml:"Item"`
  10. }
  12. type Item struct {
  13.     DealNo   string
  14.     ItemNo   null.Int
  15.     Name     string
  16.     Price    null.Float
  17.     Quantity null.Float
  18.     Place    string
  19. }
  21. func main(){
  22.     data := `
  23.     <Items>
  24.         <Item>
  25.                 <DealNo/>
  26.                 <ItemNo>32435</ItemNo>
  27.                 <Name>dsffdf</Name>
  28.                 <Price>135.12</Price>
  29.                 <Quantity></Quantity>
  30.                 <Place>dsffs</Place>
  31.             </Item>
  32.             <Item>
  33.                 <DealNo/>
  34.                 <ItemNo></ItemNo>
  35.                 <Name>dsfsfs</Name>
  36.                 <Price></Price>
  37.                 <Quantity>1.5</Quantity>
  38.                 <Place>sfsfsfs</Place>
  39.             </Item>
  40.             </Items>`
  42. var xmlMsg Items
  44.         if err := xml.Unmarshal([]byte(data), &xmlMsg); err != nil {
  45.     fmt.Println("Error: cannot unmarshal xml from web ", err)
  46.     } else {
  47.         fmt.Println("XML: ", xmlMsg)
  48.     }
  49. }
英文:

You can use "github.com/guregu/null" package. It helps:

  1. package main
  2. import (
  3. &quot;fmt&quot;
  4. 	&quot;encoding/xml&quot;
  5. 	&quot;github.com/guregu/null&quot;
  6. )
  8. type Items struct{
  9. 	It []Item `xml:&quot;Item&quot;`
  10. }
  12. type Item struct {
  13. 	DealNo   string
  14. 	ItemNo   null.Int
  15. 	Name     string
  16. 	Price    null.Float
  17. 	Quantity null.Float
  18. 	Place    string
  19. }
  21. func main(){
  22. 	data := `
  23. 	&lt;Items&gt;
  24. 		&lt;Item&gt;
  25. 	            &lt;DealNo/&gt;
  26. 	            &lt;ItemNo&gt;32435&lt;/ItemNo&gt;
  27. 	            &lt;Name&gt;dsffdf&lt;/Name&gt;
  28. 	            &lt;Price&gt;135.12&lt;/Price&gt;
  29. 	            &lt;Quantity&gt;&lt;/Quantity&gt;
  30. 	            &lt;Place&gt;dsffs&lt;/Place&gt;
  31. 	        &lt;/Item&gt;
  32. 	        &lt;Item&gt;
  33. 	            &lt;DealNo/&gt;
  34. 	            &lt;ItemNo&gt;&lt;/ItemNo&gt;
  35. 	            &lt;Name&gt;dsfsfs&lt;/Name&gt;
  36. 	            &lt;Price&gt;&lt;/Price&gt;
  37. 	            &lt;Quantity&gt;1.5&lt;/Quantity&gt;
  38. 	            &lt;Place&gt;sfsfsfs&lt;/Place&gt;
  39. 	        &lt;/Item&gt;
  40. 			&lt;/Items&gt;`
  42. var xmlMsg Items
  44.         if err := xml.Unmarshal([]byte(data), &amp;xmlMsg); err != nil {
  45. 		fmt.Println(&quot;Error: cannot unmarshal xml from web &quot;, err)
  46. 		} else {
  47. 			fmt.Println(&quot;XML: &quot;, xmlMsg)
  48. 		}
  49. }

huangapple
  • 本文由 发表于 2013年7月10日 21:42:48
  • 转载请务必保留本文链接：https://go.coder-hub.com/17572220.html
  • go
匿名

发表评论

匿名网友

:?: :razz: :sad: :evil: :!: :smile: :oops: :grin: :eek: :shock: :???: :cool: :lol: :mad: :twisted: :roll: :wink: :idea: :arrow: :neutral: :cry: :mrgreen:

确定