How to parse XML files and filter nodes using XML processing functions in Go language?

How to use XML processing functions in Go language to parse XML files and filter nodes?

In the Go language, we can use the standard library encoding/xml to process XML files. encoding/xml Provides a series of functions and structures to help us quickly parse XML files and filter out the required nodes as needed. This article will introduce how to use the XML processing function in the Go language to parse XML files and filter nodes, and provide corresponding code examples.

First, we need to import the encoding/xml package:

import (
    "encoding/xml"
    "fmt"
    "io/ioutil"
    "os"
)

Assume we have an XML file with the path ./data.xml, The content of the XML file is as follows:

<?xml version="1.0" encoding="UTF-8"?>
<root>
    <person>
        <name>张三</name>
        <age>25</age>
    </person>
    <person>
        <name>李四</name>
        <age>30</age>
    </person>
    <person>
        <name>王五</name>
        <age>35</age>
    </person>
</root>

We first need to define a structure to store the parsed XML data. Suppose we parse each <person> node into a Person structure:

type Person struct {
    Name string `xml:"name"`
    Age  int    `xml:"age"`
}

Next, we can use xml.Unmarshal() The function parses the XML file into a structure slice, the code is as follows:

func main() {
    file, err := os.Open("./data.xml")
    if err != nil {
        fmt.Println("打开文件失败:", err)
        return
    }
    defer file.Close()

    data, err := ioutil.ReadAll(file)
    if err != nil {
        fmt.Println("读取文件失败:", err)
        return
    }

    var persons []Person
    err = xml.Unmarshal(data, &persons)
    if err != nil {
        fmt.Println("解析XML文件失败:", err)
        return
    }

    fmt.Println(persons)
}

Run the above code, we can see the output as follows:

[{张三 25} {李四 30} {王五 35}]

Next, we can filter as needed out of a specific node. For example, if we only want to obtain information about people aged 30 or above, we can use the following code:

func main() {
    file, err := os.Open("./data.xml")
    if err != nil {
        fmt.Println("打开文件失败:", err)
        return
    }
    defer file.Close()

    data, err := ioutil.ReadAll(file)
    if err != nil {
        fmt.Println("读取文件失败:", err)
        return
    }

    var persons []Person
    err = xml.Unmarshal(data, &persons)
    if err != nil {
        fmt.Println("解析XML文件失败:", err)
        return
    }

    var filteredPersons []Person
    for _, person := range persons {
        if person.Age >= 30 {
            filteredPersons = append(filteredPersons, person)
        }
    }

    fmt.Println(filteredPersons)
}

Run the above code, we can see the output as follows:

[{李四 30} {王五 35}]

Through the above code example , we can see how to use the XML processing function in the Go language to parse the XML file and filter out the required nodes. You can modify the code according to actual needs to perform more complex XML parsing and filtering operations.

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