package main

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

func main() {
	// src is the input for which we want to print the AST.
	src := `
// @router /login [post]
// @router2 /login2 [post]
package main
func main() {
	println("Hello, World!")
}
`

	// Create the AST by parsing src.
	fset := token.NewFileSet() // positions are relative to fset
	f, err := parser.ParseFile(fset, "", src, parser.ParseComments)
	if err != nil {
		panic(err)
	}
	for _, comment := range f.Comments {
		fmt.Println(comment.Text())
	}

	// Print the AST.
	ast.Print(fset, f)

}

运行结果如下：

@router /login [post]
@router2 /login2 [post]

     0  *ast.File {
     1  .  Doc: *ast.CommentGroup {
     2  .  .  List: []*ast.Comment (len = 2) {
     3  .  .  .  0: *ast.Comment {
     4  .  .  .  .  Slash: 2:1
     5  .  .  .  .  Text: "// @router /login [post]"
     6  .  .  .  }
     7  .  .  .  1: *ast.Comment {
     8  .  .  .  .  Slash: 3:1
     9  .  .  .  .  Text: "// @router2 /login2 [post]"
    10  .  .  .  }
    11  .  .  }
    12  .  }
    13  .  Package: 4:1
    14  .  Name: *ast.Ident {
    15  .  .  NamePos: 4:9
    16  .  .  Name: "main"
    17  .  }
    18  .  Decls: []ast.Decl (len = 1) {
    19  .  .  0: *ast.FuncDecl {
    20  .  .  .  Name: *ast.Ident {
    21  .  .  .  .  NamePos: 5:6
    22  .  .  .  .  Name: "main"
    23  .  .  .  .  Obj: *ast.Object {
    24  .  .  .  .  .  Kind: func
    25  .  .  .  .  .  Name: "main"
    26  .  .  .  .  .  Decl: *(obj @ 19)
    27  .  .  .  .  }
    28  .  .  .  }
    29  .  .  .  Type: *ast.FuncType {
    30  .  .  .  .  Func: 5:1
    31  .  .  .  .  Params: *ast.FieldList {
    32  .  .  .  .  .  Opening: 5:10
    33  .  .  .  .  .  Closing: 5:11
    34  .  .  .  .  }
    35  .  .  .  }
    36  .  .  .  Body: *ast.BlockStmt {
    37  .  .  .  .  Lbrace: 5:13
    38  .  .  .  .  List: []ast.Stmt (len = 1) {
    39  .  .  .  .  .  0: *ast.ExprStmt {
    40  .  .  .  .  .  .  X: *ast.CallExpr {
    41  .  .  .  .  .  .  .  Fun: *ast.Ident {
    42  .  .  .  .  .  .  .  .  NamePos: 6:2
    43  .  .  .  .  .  .  .  .  Name: "println"
    44  .  .  .  .  .  .  .  }
    45  .  .  .  .  .  .  .  Lparen: 6:9
    46  .  .  .  .  .  .  .  Args: []ast.Expr (len = 1) {
    47  .  .  .  .  .  .  .  .  0: *ast.BasicLit {
    48  .  .  .  .  .  .  .  .  .  ValuePos: 6:10
    49  .  .  .  .  .  .  .  .  .  Kind: STRING
    50  .  .  .  .  .  .  .  .  .  Value: "\"Hello, World!\""
    51  .  .  .  .  .  .  .  .  }
    52  .  .  .  .  .  .  .  }
    53  .  .  .  .  .  .  .  Ellipsis: -
    54  .  .  .  .  .  .  .  Rparen: 6:25
    55  .  .  .  .  .  .  }
    56  .  .  .  .  .  }
    57  .  .  .  .  }
    58  .  .  .  .  Rbrace: 7:1
    59  .  .  .  }
    60  .  .  }
    61  .  }
    62  .  Scope: *ast.Scope {
    63  .  .  Objects: map[string]*ast.Object (len = 1) {
    64  .  .  .  "main": *(obj @ 23)
    65  .  .  }
    66  .  }
    67  .  Unresolved: []*ast.Ident (len = 1) {
    68  .  .  0: *(obj @ 41)
    69  .  }
    70  .  Comments: []*ast.CommentGroup (len = 1) {
    71  .  .  0: *(obj @ 1)
    72  .  }
    73  }