查看新闻/公告--[备忘]网页写个简单的http请求代理

/**
     * 门店网页代理.
     *
     * @param shopId 门店Id
     */
    @RequestMapping("/proxy/{shopId}/**")
    public void proxyQuery(@PathVariable String shopId,
                            @RequestBody(required = false) String requestBody,
                             HttpServletRequest request,
                             HttpServletResponse response) throws IOException {

        //请求可能是vue发起的，或nginx中转的，所以根据request拼接可能不正确，需要配置文件指定
        //http://192.168.26.135:9000/api/shop-result
        String callbackUrl = applicationProperties.getRpcCallbackUrl();
        callbackUrl = callbackUrl.substring(0, callbackUrl.indexOf("/api/"));
        String baseUrl = callbackUrl + "/proxy/" + shopId + "/";

        // 获取要代理的路径
        //http://localhost:18080/proxy/530/xxx/cache/view/query
        // 去掉 /proxy/{id} 前缀，提取剩余部分
        String fullPath = request.getRequestURI();
        String proxyPath = fullPath.substring(fullPath.indexOf(shopId) + shopId.length());
        System.out.println("proxy Path: " + proxyPath);

        // 获取查询参数部分
        String queryString = request.getQueryString();
        if (queryString != null) {
            proxyPath += "?" + queryString;
        }
        System.out.println("proxyPath: " + proxyPath);

        //请求头
        Map<String, String> headersMap = new HashMap<>();
        Enumeration<String> headerNames = request.getHeaderNames();
        while (headerNames.hasMoreElements()) {
            String headerName = headerNames.nextElement();
            if(headerName.toLowerCase().equals("accept-encoding")){
                continue;
            }
            headersMap.put(headerName, request.getHeader(headerName));
        }
        headersMap.put("Accept-Encoding", "identity"); //要求明文返回

        //通过tcp调用，获取返回结果
        String content = "....";

        //http结果的JSON
        JSONObject json = JSONObject.fromObject(content);
        int responseCode = json.getInt("responseCode");
        String responseMessage = json.getString("responseMessage");
        Map<String, List<String>> headers = (Map<String, List<String>>)json.get("headerFields");

        // 添加所有头字段
        if(headers!=null) {
            for (Map.Entry<String, List<String>> entry : headers.entrySet()) {
                String headerName = entry.getKey();
                // 跳过null键(状态行)
                if (headerName != null) {
                    if(headerName.toLowerCase().equals("transfer-encoding")){
                        continue;
                    }
                    if(headerName.toLowerCase().equals("content-encoding")){
                        continue;
                    }
                    for (String value : entry.getValue()) {
                        response.addHeader(headerName, value);
                    }
                }
            }
        }
        // 设置状态码
        response.setStatus(responseCode);

        //内容
        if(json.containsKey("webContent")) {
            String webContent = json.getString("webContent");

            //<link rel="shortcut icon" href=static/favicon.png type=image/png>
            //<link href=/xxx/
            //<script type=text/javascript src=/xxx
            //资源路径不能以斜杠开头，否则无视base了。
            if (webContent.contains("<head>")) {
                webContent = webContent.replace("<head>", "<head><base href=\"" + baseUrl + "\">");
                webContent = webContent.replace("<link href=/xxx/", "<link href=xxx/");
                webContent = webContent.replace("<script type=text/javascript src=/xxx", "<script type=text/javascript src=xxx");

                //<form id='item_menu_form' action="/xxx/cache/view/itemMenu"
                //<form id='main_form' action="/xxx/cache/view/query"
                webContent = webContent.replace("action=\"/xxx","action=\"xxx");
            }
            byte[] data = webContent.getBytes("UTF-8");
            response.setContentLength(data.length);
            response.getOutputStream().write(data);
        }else{
            response.getOutputStream().write("error".getBytes("UTF-8"));
        }
        response.getOutputStream().close();
    }

/**
     * 获取网页内容.
     *
     * @param url 网址
     * @return
     */
    private Map<String, Object> getUrlContent(String url,String requestMethod,Map<String, String> headersMap,String body) {

        Map<String, Object> data = new HashMap<>();

        HttpURLConnection conn = null;
        try {
            conn = (HttpURLConnection) new URL(url).openConnection();
            conn.setRequestMethod(requestMethod);
            conn.setConnectTimeout(5000);    // 连接超时 5秒
            conn.setReadTimeout(10000);      // 读取超时 10秒

            //header信息
            if (requestMethod.equals("POST")) {
                if (headersMap != null) {
                    for (String key : headersMap.keySet()) {
                        conn.setRequestProperty(key, headersMap.get(key));
                    }
                }

                //body内容
                if (body != null && body.length() > 0) {
                    conn.setDoOutput(true);
                    try (OutputStream out = conn.getOutputStream()) {
                        out.write(body.getBytes("UTF-8"));
                    }
                }
            }

            // 检查 HTTP 响应码（如 200 表示成功）
            int responseCode = conn.getResponseCode();
            if (responseCode == HttpURLConnection.HTTP_OK) {
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                try (InputStream in = conn.getInputStream()) {
                    byte[] buffer = new byte[8192];
                    int bytesRead;
                    while ((bytesRead = in.read(buffer)) != -1) {
                        baos.write(buffer, 0, bytesRead);
                    }
                }

                byte[] fullContent = baos.toByteArray();
                data.put("webContent", new String(fullContent, "UTF-8"));

            }
            data.put("headerFields", filterNullKey(conn.getHeaderFields()));
            data.put("responseCode", responseCode);
            data.put("responseMessage", conn.getResponseMessage());

        } catch (Exception e) {
            log.error("发生错误：", e);
            data.put("responseCode", "500");
            data.put("responseMessage", e.getMessage());
        } finally {
            if (conn != null) {
                conn.disconnect(); // 确保连接关闭
            }
        }
        return data;
    }