// Body represents the response body. // // The response body is streamed on demand as the Body field // is read. If the network connection fails or the server // terminates the response, Body.Read calls return an error. // // The http Client and Transport guarantee that Body is always // non-nil, even on responses without a body or responses with // a zero-length body. It is the caller's responsibility to // close Body. The default HTTP client's Transport may not // reuse HTTP/1.x "keep-alive" TCP connections if the Body is // not read to completion and closed. // // The Body is automatically dechunked if the server replied // with a "chunked" Transfer-Encoding. // // As of Go 1.12, the Body will also implement io.Writer // on a successful "101 Switching Protocols" response, // as used by WebSockets and HTTP/2's "h2c" mode.

// The default HTTP client's Transport does not // attempt to reuse HTTP/1.0 or HTTP/1.1 TCP connections // ("keep-alive") unless the Body is read to completion and is // closed.

大家看到里面的话，只有当 body 读取并关闭，而我上面的代码只是关闭了，Body 并没有读取。所以导致了 client 没有 reuse TCP connection。

所以这个完全明白了，我们必须在关闭之前完全的读取 Body 里面的数据，我把原来的代码改成了下面之后就解决了问题

重用

package main

import (
    "io"
    "io/ioutil"
    "net/http"
)

func main() {
    count := 100
    for i := 0; i < count; i++ {
        resp, err := http.Get("https://www.oschina.net")
        if err != nil {
            panic(err)
        }

        io.Copy(ioutil.Discard, resp.Body)
        resp.Body.Close()
    }
}

不重用

package main

import (
    "io"
    "io/ioutil"
    "net/http"
)

func main() {
    count := 100
    for i := 0; i < count; i++ {
        resp, err := http.Get("https://www.oschina.net")
        if err != nil {
            panic(err)
        }

        //io.Copy(ioutil.Discard, resp.Body)
        resp.Body.Close()
    }
}

本人也亲测证明了这一点

https://gocn.vip/topics/10626

https://gocn.vip/topics/10626