golang读取注释内容的两种方法

package main

import (
    "bufio"
    "fmt"
    "io"
    "os"
)

func main() {
    f, err := os.Open("example.go")
    if err != nil {
        fmt.Println(err)
        return
    }

    defer f.Close()

    r := bufio.NewReader(f)

    for {
        line, err := r.ReadString('\n')
        if err != nil && err != io.EOF {
            fmt.Println(err)
            break
        }

        if len(line) > 1 && line[0] == '/' && line[1] == '/' {
            fmt.Println("single line comment: ", line)
        } else if len(line) > 1 && line[0] == '/' && line[1] == '*' {
            fmt.Println("multi line comment start: ", line)

            for {
                line, err := r.ReadString('\n')
                if err != nil {
                    fmt.Println(err)
                    break
                }

                fmt.Println("multi line comment: ", line)

                if len(line) > 1 && line[len(line)-2] == '*' && line[len(line)-1] == '/' {
                    fmt.Println("multi line comment end")
                    break
                }
            }
        }
    }
}

package main

import (
    "fmt"
    "go/ast"
    "go/parser"
    "go/token"
    "os"
)

func main() {
    fset := token.NewFileSet()
    f, err := parser.ParseFile(fset, "example.go", nil, parser.ParseComments)
    if err != nil {
        fmt.Println(err)
        return
    }

    for _, c := range f.Comments {
        fmt.Println("comment: ", c.Text())
    }

    ast.Inspect(f, func(n ast.node) bool {
        switch x := n.(type) {
        case *ast.FuncDecl:
            if x.Doc != nil {
                fmt.Println("func comment: ", x.Doc.Text())
            }
        case *ast.Field:
            if x.Doc != nil {
                fmt.Println("field comment: ", x.Doc.Text())
            }
        }

        return true
    })
}