chan其实是一个队列，而且是一个带有锁等待功能的队列，因此用它可以做很多任务队列相关的工作，比如说连接池。最近打算用go来写一个小的软件配置管理系统，使用中发现没有连接池，于是就是chan写了一个简单的，使用了一下发现相当好用。

var <a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>Pool chan *<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>.<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a> func get<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>() *<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>.<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a> { if <a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>Pool == nil { <a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>Pool = make(chan *<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>.<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>,MAX_POOL_SIZE) } if len(<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>Pool) == 0 { go func() { for i := 0; i < MAX_POOL_SIZE/2; i++ { <a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a> := <a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>.New() err := <a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>.Connect("127.0.0.1","root","","wgt",3306) if err != nil { panic(err.String()) } put<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>(<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>) } }() } return <-<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>Pool } func put<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>(conn *<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>.<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>) { if <a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>Pool == nil { <a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>Pool = make(chan *<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>.<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>,MAX_POOL_SIZE) } if len(<a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>Pool) == MAX_POOL_SIZE { conn.Close() return } <a href="https://www.jb51.cc/tag/MysqL/" target="_blank" class="keywords">MysqL</a>Pool <- conn }

短短几十行代码就可以实现一个较为完美的连接池功能，go语言的表现力确实很令人兴奋。