Customize exception handling process in Golang

Customizing the exception handling process in Go includes the following steps: Define a custom type that implements the error interface to contain additional error information. Use the errors.As function to convert errors to a custom type to access additional information. Process information in custom types as needed, such as extracting error codes or error messages. Perform specific actions by creating flexible and informative error handling mechanisms.

Customize the exception handling process in Go

Exception handling in Go is through the built-in error An interface implementation that defines the Error() method to return an error message. Although it provides a simple way to handle errors, sometimes more granular control of the error handling process is required.

Go provides the ability to customize the exception handling process, allowing custom behaviors to be executed in specific scenarios.

Custom type

The first step is to define a custom type that will implement the error interface. This allows additional information to be associated with the error, such as an error code or other contextual data:

import "fmt"

// CustomError 自定义的错误类型
type CustomError struct {
    code  int
    error error
}

func (e *CustomError) Error() string {
    return fmt.Sprintf("Code: %d, Error: %s", e.code, e.error)
}

Error handling

Next, you can use errors.As The function converts the error to a custom type in order to extract additional information:

// 处理错误
func HandleError(err error) {
    var customError *CustomError

    if errors.As(err, &customError) {
        fmt.Println("错误代码：", customError.code)
        fmt.Println("错误信息：", customError.error)
    } else {
        // 不是自定义错误，进行默认处理
        fmt.Println("无法处理此错误。", err)
    }
}

Practical case

Consider a function that needs to call an external API. This function may return an error indicating whether the request was successful, the error code, and the error message:

func CallAPI() (*Response, error) {
    // ...
    return nil, &CustomError{
        code:  400,
        error: errors.New("请求无效。"),
    }
}

In the main function, the HandleError function can be called to handle requests from CallAPI Error, extract and print custom error information:

func main() {
    res, err := CallAPI()
    if err != nil {
        HandleError(err)
    } else {
        fmt.Println("API 调用成功。", res)
    }
}

By customizing the exception handling process, you can create a more flexible and informative error handling mechanism, allowing applications to perform different operations based on specific error scenarios.

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