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```

Browse Source 
docs(error): 更新defer机制文档并添加实际代码示例

- 修改panicHandler函数名称替换recoverHandler
- 在README.md中添加完整的defer执行流程代码示例
- 展示数据库连接和HTTP服务器关闭的defer应用场景
- 更新drawio图表展示defer hook调用机制和执行顺序
- 添加多个defer语句的实际应用案例
```
This commit is contained in:
yumaojun03 2026-01-25 17:13:22 +08:00
parent bb8564ba49
commit 2e443239a1
3 changed files with 126 additions and 28 deletions
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52
day03/error/README.md
View File

@ -156,4 +156,56 @@ func main() {
函数执行完成后，调用你的defer 函数进行 资源清理或者崩溃恢复 函数执行完成后，调用你的defer 函数进行 资源清理或者崩溃恢复
一个 流程(协程)里面，可以有个defer语句，声明 函数执行完成后的Hook调用
```go
func main() {
defer panicHandler()
// if r := recover(); r != nil {
// fmt.Println("Recovered from panic:", r)
// os.Exit(1)
// }
// 变量目录, 打印了文件名称
err := walkDir("./xxxx", func(filePath string) {
fmt.Println(filePath)
})
if err != nil {
if errors.Is(err, os.ErrNotExist) {
fmt.Println("not exist", err)
} else {
fmt.Printf("%s", err)
}
// os.Exit(1)
}
// 初始化数据库，连接数据库
defer func() {
fmt.Println("关闭数据库连接")
}()
// pannic
// arrs := []int{1, 2, 3}
// fmt.Println(arrs[4])
// if r := recover(); r != nil {
// fmt.Println("Recovered from panic:", r)
// os.Exit(1)
// }
// 启动API服务器 HTTP Server
defer func() {
fmt.Println("关闭HTTP服务器")
}()
}
// not exist walkDir error
// open ./xxxx: no such file or directory
// 关闭HTTP服务器
// 关闭数据库连接
// panic handler
```

21
day03/error/main.go
View File

@ -8,7 +8,8 @@ import (
var ErrFileNotFound = errors.New("file not found") var ErrFileNotFound = errors.New("file not found")
func recoverHandler() { func panicHandler() {
fmt.Println("panic handler")
if r := recover(); r != nil { if r := recover(); r != nil {
fmt.Println("Recovered from panic:", r) fmt.Println("Recovered from panic:", r)
os.Exit(1) os.Exit(1)
@ -16,7 +17,7 @@ func recoverHandler() {
} }
func main() { func main() {
defer recoverHandler() defer panicHandler()
// if r := recover(); r != nil { // if r := recover(); r != nil {
// fmt.Println("Recovered from panic:", r) // fmt.Println("Recovered from panic:", r)
@ -37,14 +38,26 @@ func main() {
// os.Exit(1) // os.Exit(1)
} }
// 初始化数据库，连接数据库
defer func() {
// db.Close()
fmt.Println("关闭数据库连接")
}()
// pannic // pannic
arrs := []int{1, 2, 3} // arrs := []int{1, 2, 3}
fmt.Println(arrs[4]) // fmt.Println(arrs[4])
// if r := recover(); r != nil { // if r := recover(); r != nil {
// fmt.Println("Recovered from panic:", r) // fmt.Println("Recovered from panic:", r)
// os.Exit(1) // os.Exit(1)
// } // }
// 启动API服务器 HTTP Server
defer func() {
// httpServer.Shutdown()
fmt.Println("关闭HTTP服务器")
}()
} }
// 最常见的就是 遍历目录里面的文件 // 最常见的就是 遍历目录里面的文件

81
day03/error/mpg.drawio
View File

@ -1,86 +1,119 @@
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