关于Etree XML官方文档
etree
The etree package is a lightweight, pure go package that expresses XML in the form of an element tree. Its design was inspired by the Python ElementTree module.
Some of the package's capabilities and features:
Represents XML documents as trees of elements for easy traversal.
Imports, serializes, modifies or creates XML documents from scratch.
Writes and reads XML to/from files, byte slices, strings and io interfaces.
Performs simple or complex searches with lightweight XPath-like query APIs.
Auto-indents XML using spaces or tabs for better readability.
Implemented in pure go; depends only on standard go libraries.
Built on top of the go encoding/xml package.
范例1：创建一个XML文档
package main
import (
"os"
etree "github.com/beevik/etree"
)
func main() {
doc := etree.NewDocument()
doc.CreateProcInst("xml", `version="1.0" encoding="UTF-8"`)
doc.CreateProcInst("xml-stylesheet", `type="text/xsl" href="style.xsl"`)
people := doc.CreateElement("People")
people.CreateComment("These are all known people")
jon := people.CreateElement("Person")
jon.CreateAttr("name", "Jon")
sally := people.CreateElement("Person")
sally.CreateAttr("name", "Sally")
doc.Indent(2)
doc.WriteTo(os.Stdout)
}
输出：
eading an XML file
Suppose you have a file on disk called bookstore.xml containing the following data:
Giada De Laurentiis
2005
30.00
J K. Rowling
2005
29.99
James McGovern
Per Bothner
Kurt Cagle
James Linn
Vaidyanathan Nagarajan
2003
49.99
Erik T. Ray
2003
39.95
This code reads the file's contents into an etree document.
doc := etree.NewDocument()
if err := doc.ReadFromFile("bookstore.xml"); err != nil {
panic(err)
}
You can also read XML from a string, a byte slice, or an io.Reader.
Processing elements and attributes
This example illustrates several ways to access elements and attributes using etree selection queries.
root := doc.SelectElement("bookstore")
fmt.Println("ROOT element:", root.Tag)
for _, book := range root.SelectElements("book") {
fmt.Println("CHILD element:", book.Tag)
if title := book.SelectElement("title"); title != nil {
lang := title.SelectAttrValue("lang", "unknown")
fmt.Printf(" TITLE: %s (%s)\n", title.Text(), lang)
}
for _, attr := range book.Attr {
fmt.Printf(" ATTR: %s=%s\n", attr.Key, attr.Value)
}
}
完整实例：
package main
import (
"fmt"
etree "github.com/beevik/etree"
)
func main() {
doc := etree.NewDocument()
if err := doc.ReadFromFile("bookstore.xml"); err != nil {
panic(err)
}
root := doc.SelectElement("bookstore")
fmt.Println("ROOT element:", root.Tag)
for _, book := range root.SelectElements("book") {
fmt.Println("CHILD element:", book.Tag)
if title := book.SelectElement("title"); title != nil {
lang := title.SelectAttrValue("lang", "unknown")
fmt.Printf(" TITLE: %s (%s)\n", title.Text(), lang)
}
for _, attr := range book.Attr {
fmt.Printf(" ATTR: %s=%s\n", attr.Key, attr.Value)
}
}
}
输出：
ROOT element: bookstore
CHILD element: book
TITLE: Everyday Italian (en)
ATTR: category=COOKING
CHILD element: book
TITLE: Harry Potter (en)
ATTR: category=CHILDREN
CHILD element: book
TITLE: XQuery Kick Start (en)
ATTR: category=WEB
CHILD element: book
TITLE: Learning XML (en)
ATTR: category=WEB
Path queries
This example uses etree's path functions to select all book titles that fall into the category of 'WEB'. The double-slash prefix in the path causes the search for book elements to occur recursively; book elements may appear at any level of the XML hierarchy.
for _, t := range doc.FindElements("//book[@category='WEB']/title") {
fmt.Println("Title:", t.Text())
}
Output:
Title: XQuery Kick Start
Title: Learning XML
This example finds the first book element under the root bookstore element and outputs the tag and text of each of its child elements.
for _, e := range doc.FindElements("./bookstore/book[1]/*") {
fmt.Printf("%s: %s\n", e.Tag, e.Text())
}
Output:
title: Everyday Italian
author: Giada De Laurentiis
year: 2005
price: 30.00
This example finds all books with a price of 49.99 and outputs their titles.
path := etree.MustCompilePath("./bookstore/book[p:price='49.99']/title")
for _, e := range doc.FindElementsPath(path) {
fmt.Println(e.Text())
}
Output:
Note that this example uses the FindElementsPath function, which takes as an argument a pre-compiled path object. Use precompiled paths when you plan to search with the same path more than once.
Other features
These are just a few examples of the things the etree package can do. See the documentation for a complete description of its capabilities.
Contributing
This project accepts contributions. Just fork the repo and submit a pull request!
etree作为一个***在解析XML文件的工具中占据着很重要的地位，它可以查找节点，轮询、生成XML文件。
一、XML的引入写法
在工程中引入XML的方法，建议用第一种
//方法一
xml := `
Charles Dickens
James Joyce
`
//方法二
LoginPut= "" +
" " +
" " +
" " +
" " +
" %s" +
" %s" +
" "
二、XML的解析
1. 判断所需节点是否存在的方法
方法1：在某个节点范围下查找指定节点是否存在
//whetherExistNode 判断节点是否存在
func whetherExistNode(doc etree.Element, nodeName string) (exist bool) {
path := etree.MustCompilePath(nodeName)
bb := doc.FindElementPath(path)
if bb != nil {
return true
} else {
return false
}
return exist
}
方法2：获取指定节点的值
//getSpecifiedNodeVal 获取指定节点的值
func getSpecifiedNodeVal(doc etree.Document, nodeName string) (dataSlice []string) {
path := etree.MustCompilePath(nodeName)
var val string
for _, t := range doc.FindElementsPath(path) {
val = t.Text()
if len(dataSlice) <= 0 {
dataSlice = append(dataSlice, val)
} else {
repeat := false
for i := 0; i
方法3：在用SelectElement获取节点值的时候 要判断改节点是否存在，如果不加判断，程序直接就会panic退出，后果会比较严重。
if tempNode.SelectElement("OperatingSystemVersion") != nil {
systemVersion = tempNode.SelectElement("OperatingSystemVersion").Text()
if systemVersion != "" {
systemType = util.GetOSType(systemVersion)
}
} else {
systemVersion = ""
}
注意点：在用FindElementsPath或FindElements查找节点时建议用FindElementsPath，因为FindElements在查找不到节点时会panic报错，SelectElement和SelectElements,的用法，SelectElements获取到的结果为数组，SelectElement标识选中的单一的节点。
path := etree.MustCompilePath("//PartitionName")
doc.FindElementsPath(path)
重点：1.在获取节点值的时候一定要判断节点是否为空
2.添加//标识从头开始查找值
3.doc.SelectElement必须选中开始的父节点，不能跨区域
//FindElementPath 指定父节点查找指定的接点值:节点不存在不会报错
aa := doc.SelectElement("feed").SelectElement("entry")
path := etree.MustCompilePath("updatedd")
cc := aa.FindElementPath(path)
if cc != nil {
fmt.Println(cc.Text())
} else {
fmt.Println("cc == nil")
}
2.etree支持接口返回内容和XML文件两种解析方式
测试用的data.xml文件
5134c4aa-8df4-3d41-aafc-927a7546f8b8
2019-09-25T03:03:29.615Z
IBM Power Systems Management Console
323F5D6D-E501-4166-9522-B216B1565862
2019-09-25T03:03:29.914Z
IBM Power Systems Management Console
-170243083
21FE0160-FF83-4852-909B-B7D264E258C8
2019-09-25T03:03:29.916Z
IBM Power Systems Management Console
-1052118977
var testData string = `
21FE0160-FF83-4852-909B-B7D264E258C8
2019-09-25T03:03:29.916Z
IBM Power Systems Management Console
-1052118977
`
package main
import (
"fmt"
etree "github.com/beevik/etree"
)
var testData string = `
21FE0160-FF83-4852-909B-B7D264E258C8
2019-09-25T03:03:29.916Z
IBM Power Systems Management Console
-1052118977
`
func main() {
//读取字符串的方法-----------采用绝对路径的方法
doc := etree.NewDocument()
if err := doc.ReadFromString(testData); err != nil {
panic(err)
}
res := doc.FindElement("./entry[0]/id").Text()
fmt.Println(res)
// doc := etree.NewDocument()
// if err := doc.ReadFromFile("data.xml"); err != nil {
// panic(err)
// }
// servers := doc.SelectElement("feed")
// for _, server := range servers.SelectElements("entry") {
// if server.SelectElement("author").SelectElement("name") == nil {
// fmt.Println("测试节点不存在")
// } else {
// fmt.Println(server.SelectElement("author").SelectElement("name").Text())
// }
// }
}
输出：
21FE0160-FF83-4852-909B-B7D264E258C8
package main
import (
"fmt"
etree "github.com/beevik/etree"
)
func main() {
doc := etree.NewDocument()
if err := doc.ReadFromFile("data.xml"); err != nil {
panic(err)
}
servers := doc.SelectElement("feed")
for _, server := range servers.SelectElements("entry") {
if server.SelectElement("author").SelectElement("name") == nil {
fmt.Println("测试节点不存在")
} else {
fmt.Println(server.SelectElement("author").SelectElement("name").Text())
}
}
}
输出：
IBM Power Systems Management Console
IBM Power Systems Management Console
京公网安备 11010802041100号