四叶草 2020-02-15
// 1. 打开浏览器,创建HttpClient对象 CloseableHttpClient httpClient = HttpClients.createDefault(); // 2.输入网址,发起get请求创建HttpGet对象 HttpGet get = new HttpGet("http://112.124.1.187/index.html?typeId=16"); // 3.发情请求,返回响应,使用HttpClient对象发起请求 CloseableHttpResponse response = httpClient.execute(get); // 4.解析响应,获取数据 if(response.getStatusLine().getStatusCode() == 200){ HttpEntity entity = response.getEntity(); String content = EntityUtils.toString(entity,"utf-8"); System.out.println(content); }
// 1. 打开浏览器,创建HttpClient对象 CloseableHttpClient httpClient = HttpClients.createDefault(); try { // 地址:http://112.124.1.187/index.html?typeId=16.带有参数 // 创建URIBuilder URIBuilder uriBuilder = new URIBuilder("http://112.124.1.187/index.html"); // 添加参数 // 多个参数可以连着添加,在后面连着setParameter(key,value) uriBuilder.setParameter("typeId","16"); // 2.输入网址,发起get请求创建HttpGet对象 HttpGet get = new HttpGet(uriBuilder.build()); // 3.发情请求,返回响应,使用HttpClient对象发起请求 CloseableHttpResponse response = null; try { response = httpClient.execute(get); // 4.解析响应,获取数据 if(response.getStatusLine().getStatusCode() == 200){ HttpEntity entity = response.getEntity(); String content = EntityUtils.toString(entity,"utf-8"); System.out.println(content); } } catch (IOException e) { e.printStackTrace(); } } catch (URISyntaxException e) { e.printStackTrace(); }
基本使用与get相同把HttpGet改为HttpPost就可以了。
// 1. 打开浏览器,创建HttpClient对象 CloseableHttpClient httpClient = HttpClients.createDefault(); // 地址:http://112.124.1.187/index.html?typeId=16.带有参数 // 2.输入网址,发起post请求创建HttpPost对象 HttpPost post = new HttpPost("http://112.124.1.187/index.html"); // 2.1 声明List集合,封装表单中的参数 List<NameValuePair> params = new ArrayList<>(); // 2.2 添加参数 params.add(new BasicNameValuePair("typeId","16")); // 2.3 创建表单的Entity对象,对参数进行url编码 UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(params,"utf-8"); // 2.4 设置表单的Entity对象到Post请求中 post.setEntity(formEntity); // 3.发情请求,返回响应,使用HttpClient对象发起请求 CloseableHttpResponse response = null; try { response = httpClient.execute(post); // 4.解析响应,获取数据 if(response.getStatusLine().getStatusCode() == 200){ HttpEntity entity = response.getEntity(); String content = EntityUtils.toString(entity,"utf-8"); System.out.println(content); } } catch (IOException e) { e.printStackTrace(); } finally{ if(response != null){ response.close(); } httpClient.close(); }
像每一个连接操作一样,HttpClent 连接一次,再断开,再要用时,继续连接,再断开。构成浪费资源现象。需要用到 "池" 这个概念。
public static void main(String[] args) { // 创建连接池管理器 PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager(); // 设置最大连接数 cm.setMaxTotal(10); // 设置每个主机最大连接数 cm.setDefaultMaxPerRoute(2); // 使用连接池管理器发起请求 doGet(cm); doGet(cm); } private static void doGet(PoolingHttpClientConnectionManager cm) { // 从连接池中获取HttpClient对象 CloseableHttpClient httpClient = HttpClients.custom().setConnectionManager(cm).build(); HttpGet httpGet = new HttpGet("http://112.124.1.187"); CloseableHttpResponse response = null; try { response = httpClient.execute(httpGet); if(response.getStatusLine().getStatusCode() == 200){ String content = EntityUtils.toString(response.getEntity(),"utf-8"); System.out.println(content.length()); } } catch (IOException e) { e.printStackTrace(); } finally{ if(response != null){ try { response.close(); } catch (IOException e) { e.printStackTrace(); } } // 不用关闭HttpClient,交由池来管理 // httpClient.close(); } }
这个请求参数不是放在url地址后面的参数,而是你在请求过程中,所涉及到需要事先定好的规则。比如,在请求过程中,有时候因为网络原因,或目标服务器的原因,请求需要更长的时间才能完成,就需要我们自定义相关的时间。
HttpGet get = new HttpGet("http://112.124.1.187/index.html?typeId=16"); // 配置请求信息 RequestConfig config = RequestConfig.custom().setConnectTimeout(10000) // 创建连接的最长时间,单位是毫秒 .setConnectionRequestTimeout(500) // 设置获取连接的最长时间,单位是毫秒 .setSocketTimeout(10 * 1000) // 设置数据传输的最长时间,单位是毫秒 .build(); // 将配置给请求 get.setConfig(config);