go源码分析(二) 使用go http包开发web时遇到的坑之重复注册Handle路由

goroutine 26 [running]:
net/http.(*ServeMux).Handle(0xc9eca0, 0x8b61dd, 0x1, 0x8fbc40, 0x8d1658)
	/usr/local/go/src/net/http/server.go:2353 +0x239
net/http.(*ServeMux).HandleFunc(0xc9eca0, 0x8b61dd, 0x1, 0x8d1658)
	/usr/local/go/src/net/http/server.go:2368 +0x55
net/http.HandleFunc(0x8b61dd, 0x1, 0x8d1658)
	/usr/local/go/src/net/http/server.go:2380 +0x4b
_/mnt/hgfs/github/jiuyinzhenjing/0002/gosrc/gopl_learn/022_go_web/server.Server()
	/mnt/hgfs/github/jiuyinzhenjing/0002/gosrc/gopl_learn/022_go_web/server/server.go:49 +0x594
created by main.main
	/mnt/hgfs/github/jiuyinzhenjing/0002/gosrc/gopl_learn/022_go_web/main.go:23 +0x50

func (mux *ServeMux) Handle(pattern string, handler Handler) {
	mux.mu.Lock()
	defer mux.mu.Unlock()

	if pattern == "" {
		panic("http: invalid pattern")
	}
	if handler == nil {
		panic("http: nil handler")
	}
	if _, exist := mux.m[pattern]; exist {
		panic("http: multiple registrations for " + pattern)
	}

	if mux.m == nil {
		mux.m = make(map[string]muxEntry)
	}
	e := muxEntry{h: handler, pattern: pattern}
	mux.m[pattern] = e
	if pattern[len(pattern)-1] == '/' {
		mux.es = appendSorted(mux.es, e)
	}

	if pattern[0] != '/' {
		mux.hosts = true
	}
}