在Go中将XML代码写入XML文件

Question

I have a script that print-lines XML code, but I need it to write a new XML file and then write the XML code to the file instead of printing it.

Here is the function that prints the XML code

func processTopic(id string, properties map[string][]string) {
    fmt.Printf("<card entity=\"%s\">
", id)
    fmt.Println("  <facts>")
    for k, v := range properties {
        for _,value := range v {
            fmt.Printf("    <fact property=\"%s\">%s</fact>
", k, value)
        }
    }
    fmt.Println("  </facts>")
    fmt.Println("</card>")
}

How can I get it to write an XML file and then write the code to that XML file?

Answer 1

To add to bgp's (+1) correct answer; by changing the function to take a io.Writer as argument, you can output your XML to any type of output implementing the io.Writer interface.

func processTopic(w io.Writer, id string, properties map[string][]string) {
    fmt.Fprintf(w, "<card entity=\"%s\">
", id)
    fmt.Fprintln(w, "  <facts>")
    for k, v := range properties {
        for _,value := range v {
            fmt.Fprintf(w, "    <fact property=\"%s\">%s</fact>
", k, value)
        }
    }
    fmt.Fprintln(w, "  </facts>")
    fmt.Fprintln(w, "</card>")
}

Printing to screen (Stdout):

processTopic(os.Stdout, id, properties)

Writing to file (code taken from bgp's answer):

f, err := os.Create("out.xml") // create/truncate the file
if err != nil { panic(err) } // panic if error
defer f.Close() // make sure it gets closed after
processTopic(f, id, properties)