Colly 报错“invalid memory address or nil pointer dereference”,如何解决?
colly 报错:“invalid memory address or nil pointer dereference”
原代码摘自问题描述:
func downloadimages(e *colly.htmlelement) { srcref := desturl + e.attr("src") res, _ := http.get(srcref) if strings.contains(srcref, "http") && strings.contains(srcref, ".jpg") { arr := strings.split(srcref, "/") filename := strings.split(arr[len(arr)-1], ".")[0] fmt.println("filename", filename) f, _ := os.create("./images/" + filename + ".jpg") defer f.close() written, _ := io.copy(f, res.body) fmt.println("info", written) } }
代码在第55行执行 os.create 操作时发生空指针引用错误。这是因为在对 srcref 进行拆分操作时,没有检查 srcref 是否为 nil,或者对应的文件和目录是否存在。
修改后的代码如下:
func downloadImages(e *colly.HTMLElement) { srcRef := destUrl + e.Attr("src") if srcRef == "" { return } res, err := http.Get(srcRef) if err != nil { log.Printf("Failed to fetch image: %v", err) return } if strings.Contains(srcRef, "http") && strings.Contains(srcRef, ".jpg") { arr := strings.Split(srcRef, "/") fileName := strings.Split(arr[len(arr)-1], ".")[0] fmt.Println("fileName", fileName) path := "./images/" + fileName + ".jpg" f, err := os.Create(path) if err != nil { log.Printf("Failed to create file: %v", err) return } defer f.Close() written, err := io.Copy(f, res.Body) if err != nil { log.Printf("Failed to write to file: %v", err) return } fmt.Println("info", written) } }
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