[TOC] > [參考](https://ieevee.com/tech/2017/11/23/go-panic.html) ## 接收異常 ### 主線程 ``` defer func() { e := recover() log.Println(e) }() panic("should set user env.") time.Sleep(1 * time.Second) fmt.Printf("i can output") //依然可以輸出 //output //2020/01/04 15:43:24 should set user env. ``` ### 在 goruntime 接收異常 實現 try...catch 的效果 在panic的當前goroutine的defer中使用recover來捕捉panic,recover只在defer的函數中有效 ``` defer fmt.Println("defer main") var user = os.Getenv("USER_") go func() { defer func() { err := recover() fmt.Println(err) }() func() { if user == "" { panic("should set user env.") //不會輸出異常 } }() }() time.Sleep(1 * time.Second) fmt.Printf("i can output") //依然可以輸出 //output //should set user env. //i can outputdefer main ```