用Java发起HTTP请求与获取状态码

柔情只为你懂 2024-04-17 18:44 58阅读 0赞

在使用Java请求Web程序比如访问WebService接口时，通常需要先判断访问URL的有效性，这里就Java发送HTTP请求的方式做简单记录，按照前辈们的说法，Java发HTTP请求，最常见的无非是两种，一种是用java.net.URLConnection，另一种则是大名鼎鼎的HttpClient。使用java.net.URLConnection比较麻烦，而HttpClient则比较简便。以发送POST请求为例

**java.net.URLConnection方法如下：**

private static void urlConnectionPost() {
        StringBuilder responseBuilder = null;
        BufferedReader reader = null;
        OutputStreamWriter wr = null;
        URL url;
        try {
            url = new URL("http://www.poorren.com");
            HttpURLConnection conn = (HttpURLConnection)url.openConnection();
            conn.setDoOutput(true);
            conn.setConnectTimeout(1000 * 5);
            wr = new OutputStreamWriter(conn.getOutputStream());
            wr.write("");
            wr.flush();
            // Get the response
            reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            responseBuilder = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                responseBuilder.append(line + "\n");
            }
            wr.close();
            reader.close();
            System.out.println(responseBuilder.toString());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

而获取状态码则只需在conn.connect();之后调用conn.getResponseCode();即可。

**HttpClient方法：**

private static void httpClientPost() {
        HttpClient client = new DefaultHttpClient();
        HttpPost post = new HttpPost("http://www.poorren.com");
        try {
            ContentProducer cp = new ContentProducer() {
                public void writeTo(OutputStream outstream) throws IOException {
                    Writer writer = new OutputStreamWriter(outstream, "UTF-8");
                    writer.write("");
                    writer.flush();
                }
            };
            post.setEntity(new EntityTemplate(cp));
            HttpResponse response = client.execute(post);
            System.out.println(EntityUtils.toString(response.getEntity()));
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

使用HttpClient的情况下获取状态码直接在execute(post/get…)后获取即可。