标签：code main info import fun imp over 使用 代码
1. defer ： 延迟调用。多个defer，依次入栈，在函数即将退出时，依次出栈调用
1 package main 2 import "fmt" 3 func main() { 4 defer func() { 5 fmt.Println("defer one") 6 }() 7 defer func() { 8 fmt.Println("defer two") 9 }() 10 defer func() { 11 fmt.Println("defer three") 12 }() 13 }
2. panic和defer结合使用：panic触发错误，defer依次出栈调用，没有recover捕获的情况下，最后才打印错误
1 package main 2 import "fmt" 3 func main() { 4 defer func() { 5 fmt.Println("defer one") 6 }() 7 defer func() { 8 fmt.Println("defer two") 9 }() 10 defer func() { 11 fmt.Println("defer three") 12 }() 13 panic("panic here") 14 }
3. defer,panic, recover 结合使用，panic触发错误，defer依次出栈调用，直到被recover捕获，打印捕获的信息，之后继续defer出栈
例一:
1 package main 2 import "fmt" 3 func main() { 4 defer func() { 5 fmt.Println("defer one") 6 }() 7 defer func() { 8 fmt.Println("defer two") 9 }() 10 defer func() { 11 if info := recover(); info != nil { 12 fmt.Println("catch: ", info) 13 } 14 fmt.Println("defer three") 15 }() 16 panic("panic here") 17 }
例二：
package main import "fmt" func main() { defer func() { fmt.Println("defer one") }() defer func() { if info := recover(); info != nil { fmt.Println("catch: ", info) } fmt.Println("defer two") }() defer func() { fmt.Println("defer three") }() panic("panic here") }
例三：
package main import "fmt" func main() { defer func() { if info := recover(); info != nil { fmt.Println("catch: ", info) } fmt.Println("defer one") }() defer func() { fmt.Println("defer two") }() defer func() { fmt.Println("defer three") }() panic("panic here") }
4. recover 必须在defer中调用，才有效，否则返回nil
package main import "fmt" func main() { if info := recover(); info != nil { fmt.Println("catch: ", info) } else { fmt.Println("recover return nil") } defer func() { fmt.Println("defer one") }() defer func() { fmt.Println("defer two") }() defer func() { fmt.Println("defer three") }() panic("panic here") }
5. panic 其后的代码不会执行
例一：
package main import "fmt" func main() { defer func() { fmt.Println("defer one") }() defer func() { fmt.Println("defer two") }() defer func() { fmt.Println("defer three") }() panic("panic here") if info := recover(); info != nil { fmt.Println("catch: ", info) } else { fmt.Println("recover return nil") } }
例二：
package main import "fmt" func main() { defer func() { fmt.Println("defer one") }() defer func() { if v := recover(); v != nil { fmt.Println("catch panic error: ", v) } fmt.Println("defer two") }() defer func() { fmt.Println("defer three") }() panic("panic here") fmt.Println("after panic") }
标签：code main info import fun imp over 使用 代码
原文地址：https://www.cnblogs.com/BluePegasus/p/10926175.html
