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Golang的異常處理

Go语言进阶学习
Go语言进阶学习轉載
2023-07-24 15:20:521355瀏覽
<span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">Golang</span>的優點很多,先前的文章中也有提到過,但也有很多槽點為Gopher所詬病,尤其是<span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">錯誤處理</span>

在說錯誤和異常之前,先要說兩個概念:

錯誤處理:錯誤是業務中的一部分,是可以預見的。

異常處理:非業務的一部分,不可預見的。

錯誤處理

首先看一下範例程式碼:

file, err := os.Open("/usr/local/test.txt")

Golang官方推薦上述程式碼中的錯誤處理方式,並建議<span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">err</span> 放在傳回值的最後。我們在日常的編碼中也需要遵循這樣的規則來定義 <span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">func</span>

在Gopher间流传着这样一个笑话:一半时间在编写代码,一半时间在写错误处理。

示例代码:

func Open(name string) (*File, error) {
   return OpenFile(name, O_RDONLY, 0)
}

但通常不是每个方法都需要处理 <span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">err</span>,可以适当的将 <span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">err</span>返回给上层函数,由上层函数统一打印或者处理错误。例如:<span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">http</span> 路由中的错误可以在路由返回数据前处理,将错误信息和错误码格式化后返回给 <span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">Client</span>

異常處理

Golang的例外處理比較特立獨行,需要<span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">defer</span> <span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">err</span> <span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">recover</span><span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">()</span>三者搭配使用,而Java只要<span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">try</span><span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">{</span><span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;"></span><span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">}</span><span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">Catch</span><span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">()</span>就可以搞定,還是來看範例程式碼:

package main

import (
    "fmt"
)

func main() {
    test()
}

func test()  {
    defer func() {
        if e := recover(); e != nil {
            fmt.Println("Worng!")
        }
    }()
    panic("panic")
}

如上代码在 <span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">test</span><span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">()</span>函数及其子函数中如果发生panic的错误,就会打印:

Worng!

代码封装

当然,在每个方法最上面写这么一大堆冗余的代码是很不优雅的,也不符合面向对象的特性:<span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">封装</span>,于是便可以封装成 <span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">CoverErrorMessage</span><span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">()</span> ,而 <span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">test</span><span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">()</span>函数改写如下:

package main

import (
    "fmt"
)

func main() {
    test()
}

func test()  {
    defer tools.CoverErrorMessage()
    panic("panic")
}

func  CoverErrorMessage() {
   if message := recover(); message != nil {
      var err error
      switch x := message.(type) {
      case string:
         err = errors.New(x)
      case error:
         err = x
      default:
         err = errors.New("Unknow panic")
      }
      Logger.Error("Recovered panic error : ",err)
   }
}

defer 处理异常时只能将 <span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">recover</span><span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">()</span>写在第一层函数中,否则将无法 <span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">recover</span><span style="box-sizing: border-box;background-image: initial;background-position: initial;background-size: initial;background-repeat: initial;background-attachment: initial;background-origin: initial;background-clip: initial;display: inline-block;padding-right: 2px;padding-left: 2px;font-size: 14px;">()</span>到panic错误

以上是Golang的異常處理的詳細內容。更多資訊請關注PHP中文網其他相關文章!

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