Go 解析XML

這是一個建立於 的文章，其中的資訊可能已經有所發展或是發生改變。

今天看了看XML的解析，挺別緻的和C++，Java之類的解析很是不同。

GO中將XMl的結構解析成一個資料結構，類似於一個結構體。

package mainimport ("encoding/xml""fmt""os")type Address struct {City, State string}type Person struct {XMLName   xml.Name `xml:"person"`Id        int      `xml:"id,attr"`FirstName string   `xml:"name>first"`LastName  string   `xml:"name>last"`Age       int      `xml:"age"`Height    float32  `xml:"height,omitempty"`Married   boolAddressComment string `xml:",comment"`}func main() {v := &Person{Id: 13, FirstName: "John", LastName: "Doe", Age: 42, Height: 172, Comment: " Need more details. "}v.Address = Address{"Hanga Roa", "Easter Island"}output, err := xml.MarshalIndent(v, "  ", "    ")if err != nil {fmt.Printf("error: %v\n", err)}os.Stdout.Write(output)}

- the XMLName field, described above, is omitted.- a field with tag "-" is omitted.- a field with tag "name,attr" becomes an attribute with  the given name in the XML element.- a field with tag ",attr" becomes an attribute with the  field name in the XML element.- a field with tag ",chardata" is written as character data,  not as an XML element.- a field with tag ",innerxml" is written verbatim, not subject  to the usual marshalling procedure.- a field with tag ",comment" is written as an XML comment, not  subject to the usual marshalling procedure. It must not contain  the "--" string within it.- a field with a tag including the "omitempty" option is omitted  if the field value is empty. The empty values are false, 0, any  nil pointer or interface value, and any array, slice, map, or  string of length zero.- an anonymous struct field is handled as if the fields of its  value were part of the outer struct.

上面是關於 那個結構的構成。

下面的兩個例子 是讀取xml的

<person id="13">      <name>          <first>John</first>          <last>Doe</last>      </name>      <age>42</age>      <height>172</height>      <Married>false</Married>      <City>Hanga Roa</City>      <State>Easter Island</State>      <!-- Need more details. --></person>

代碼1：

package mainimport ("encoding/xml""fmt"//"io""os")type Address struct {City, State string}type Person struct {XMLName   xml.Name `xml:"person"`Id        int      `xml:"id,attr"`FirstName string   `xml:"name>first"`LastName  string   `xml:"name>last"`Age       int      `xml:"age"`Height    float32  `xml:"height,omitempty"`Married   boolAddressComment string `xml:",comment"`}func main() {file, _ := os.Open("a.xml")fileinfo, _ := file.Stat()filesize := fileinfo.Size()buffer := make([]byte, filesize)file.Read(buffer)fmt.Printf("%s", buffer)person := Person{}xml.Unmarshal(buffer, &person)fmt.Println(person)fmt.Println(person.FirstName)fmt.Println(person.Age)fmt.Println(person.City)fmt.Println(person.LastName)}

代碼2：

package mainimport (    "encoding/xml"    "fmt"    //"io"    "os")type Address struct {    City, State string}type Person struct {    XMLName   xml.Name `xml:"person"`    Id        int      `xml:"id,attr"`    FirstName string   `xml:"name>first"`    LastName  string   `xml:"name>last"`    Age       int      `xml:"age"`    Height    float32  `xml:"height,omitempty"`    Married   bool    Address    Comment string `xml:",comment"`}func main() {    file, _ := os.Open("a.xml")    person := Person{}    decoder := xml.NewDecoder(file)    decoder.Decode(&person)    fmt.Println(person)}

輸出：

{{ person} 13 John Doe 42 172 false {Hanga Roa Easter Island}  Need more details. }