Method Exist

utils/lock.go:14–19

查询是否存在

(bookId int)

//查询是否存在
func (this BooksLock) Exist(bookId int) (exist bool) {
	this.Lock.RLock()
	defer this.Lock.RUnlock()
	_, exist = this.Books[bookId]
	return
}

//设置
func (this BooksLock) Set(bookId int) {