Go error handling (ii)

definition of the 1,.error interface

 
   
  

  
    
   
type error interface{
  
    
   

  
    
   
 Error() string
  
    
   
}
 
   
  

Use of 2.error

  
 

   
  

  
func Foo(param int)(n int,err error){
   
  

  
 //函数定义
   
  

  
}
   
  

  
n,err:=Foo(0)
   
  

  
if err!=nil{
   
  

  
 //错误处理
   
  

  
}else{
   
  

  
 //使用返回值n
   
  

  
}
  
 

3. Custom Error Types

• Defines a struct that hosts error messages

  
 

   
  
 
   
< Code class= "Language-go" > type  patherror    struct  { 
 
   
 op  string   
 
   
< Span class= "PLN" > path string   
 
   
  err  Span class= "PLN" > error  
 
   
}   
 
  
  
 

• Defining the Error method

  
 

   
  

  
 func (e *PathError) Error() string{
   
  

  

   
  

  
    return e.op+" "+e.path+":"+e.Err.Error()
   
  

  
}
  
 

defer: Equivalent to the filnaly in C #, is always executed, and his execution order is advanced after

   
  

    
   

   
func CopyFile(dst, src string) {
    
   

   
 defer fmt.Println(dst)
    
   

   
 defer fmt.Println(src)
    
   

   
 fmt.Println("copy")
    
   

   
}
   
  

Copy

C:\2.txt

C:\oem8.txt

Panic: equivalent to Throw,recover: equivalent to catch

  
 

   
  

  
 defer func() { //必须要先声明defer，否则不能捕获到panic异常
   
  

  
 if err := recover(); err != nil {
   
  

  
 fmt.Println(err) //这里的err其实就是panic传入的内容，55
   
  

  
 }
   
  

  
 }()
   
  

  
 f()
   
  

  

   
  

  
func f() {
   
  

  
 fmt.Println("a")
   
  

  
 panic(55)
   
  

  
 fmt.Println("b")
   
  

  
}
  
 

Output to

A

55

Here panic the fmt behind. Println ("B") was not executed, so the information behind it was not B

From for notes (Wiz)

Go error handling (ii)