Golang网络请求错误如何捕获

resp, err := http.Get("https://example.com")
if err != nil {
    log.Printf("请求失败: %v", err)
    return
}
defer resp.Body.Close()
<p>if resp.StatusCode >= 400 {
log.Printf("HTTP错误: %d", resp.StatusCode)
}</p>

client := &http.Client{
    Timeout: 10 * time.Second,
    Transport: &http.Transport{
        DialContext: (&net.Dialer{
            Timeout:   5 * time.Second,
            KeepAlive: 30 * time.Second,
        }).DialContext,
        TLSHandshakeTimeout: 5 * time.Second,
    },
}
<p>resp, err := client.Get("<a href="https://www.php.cn/link/c071c86446066d4de2ba1551614a08c8">https://www.php.cn/link/c071c86446066d4de2ba1551614a08c8</a>")
if err != nil {
log.Printf("请求异常: %v", err)
// 常见错误类型：timeout, connection refused, EOF
}</p>

resp, err := client.Do(req)
if err != nil {
    if errors.Is(err, context.DeadlineExceeded) {
        log.Println("请求超时")
    } else if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
        log.Println("网络超时")
    } else if strings.Contains(err.Error(), "connection refused") {
        log.Println("连接被拒绝")
    } else {
        log.Printf("未知错误: %v", err)
    }
    return
}

body, err := io.ReadAll(resp.Body)
if err != nil {
    log.Printf("读取响应体失败: %v", err)
    return
}
// 使用body...