How to recover from panic in Golang?

In Go, use the recover function to recover from a panic, which returns the most recent panic value from the function stack. In actual combat, you can handle io.EOF exceptions, for example: open a file and use defer to catch panic. If panic is equal to io.EOF, exit normally, otherwise panic will occur.

How to recover from panic in Golang?

In Golang, panic will cause the program to exit abnormally. Although panic is useful for handling unrecoverable errors, there are situations where you may want to recover and continue execution.

Use the recover function to recover from panic. recover will return the latest panic information from the current function function stack, and return a panic value of type interface{}.

func main() {
  // 包装可能会产生 panic 的代码
  defer func() {
    if err := recover(); err != nil {
      // 处理 panic
      fmt.Println("recovered from panic:", err)
    }
  }()

  // 可能产生 panic 的代码
  panic("this will cause a panic")
}

Practical case

The following is an example of handling io.EOF exception when reading data from a file:

package main

import (
  "fmt"
  "io"
  "os"
)

func main() {
  f, err := os.Open("data.txt")
  if err != nil {
    panic(err)
  }
  defer f.Close()

  defer func() {
    if err := recover(); err != nil {
      if err == io.EOF {
        fmt.Println("reached end of file")
      } else {
        panic(err)
      }
    }
  }()

  // 读取数据
  data := make([]byte, 1024)
  for {
    n, err := f.Read(data)
    if err != nil {
      if err == io.EOF {
        // 达到文件末尾，正常退出
        break
      } else {
        // 其他错误，引发 panic
        panic(err)
      }
    }
    // 处理读取到的数据
  }
}

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