defer
不管程序是否出现异常，均在函数退出时候，自动执行相关代码
实战
实例１
package main
import (
"fmt"
)
func main() {
defer func() {
fmt.Println("main defer")
}()
if err := test0(); err != nil {
fmt.Println(err.Error())
return
}
if err := test1(); err != nil {
fmt.Println(err.Error())
return
}
}
func test0() error {
return nil
}
func test1() error {
return nil
}运行结果
main defer实例２
package main
import (
"fmt"
"errors"
)
func main() {
defer func() {
fmt.Println("main defer")
}()
if err := test0(); err != nil {
fmt.Println(err.Error())
return
}
if err := test1(); err != nil {
fmt.Println(err.Error())
return
}
}
func test0() error {
return errors.New("test0 error")
}
func test1() error {
return nil
}运行结果
test0 error
main defer实例３
package main
import (
"fmt"
"errors"
)
func main() {
defer func() {
fmt.Println("main defer")
}()
if err := test0(); err != nil {
fmt.Println(err.Error())
return
}
if err := test1(); err != nil {
fmt.Println(err.Error())
return
}
}
func test0() error {
return nil
}
func test1() error {
return errors.New("test1 error")
}运行结果
test1 error
main defer实例４
package main
import (
"fmt"
"errors"
)
func main() {
defer func() {
fmt.Println("main defer0")
}()
defer func() {
fmt.Println("main defer1")
}()
if err := test0(); err != nil {
fmt.Println(err.Error())
return
}
if err := test1(); err != nil {
fmt.Println(err.Error())
return
}
}
func test0() error {
defer func() {
fmt.Println("test0 defer")
}()
return nil
}
func test1() error {
defer func() {
fmt.Println("test1 defer")
}()
return errors.New("test1 error")
}运行结果
test0 defer
test1 defer
test1 error
main defer1
main defer0