HttpClient发送http请求

1. pom.xml 引入坐标

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.3</version>
</dependency>

2.测试

发送GET请求

        //1.创建客户端
        CloseableHttpClient httpClient = HttpClients.createDefault();
        //2.声明get请求
        HttpGet request = new HttpGet("http://www.baidu.com");
        //3.发送请求
        CloseableHttpResponse response = httpClient.execute(request);
        //4.判断状态码
        if (response.getStatusLine().getStatusCode() == 200) {
            HttpEntity entity = response.getEntity();
            //使用工具类EntityUtils，从响应中取出实体表示的内容并转换成字符串
            String string = EntityUtils.toString(entity, "UTF-8");
            System.out.println(string);
        }
        //5.关闭资源
        response.close();
        httpClient.close();

发送POST请求

        //获取客户端
        CloseableHttpClient client = HttpClients.createDefault();
        //声明POST请求
        HttpPost request = new HttpPost("https://gitee.com/oauth/token");
        //设置User-Agent
        request.addHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36");
        //构建请求参数
        ArrayList<NameValuePair> parameters = new ArrayList<>();
        parameters.add(new BasicNameValuePair("grant_type", "authorization_code"));
        parameters.add(new BasicNameValuePair("code", "xxx"));
        parameters.add(new BasicNameValuePair("client_id", "xxx"));
        parameters.add(new BasicNameValuePair("client_secret", "xxx"));
        parameters.add(new BasicNameValuePair("redirect_uri", "http://localhost:8001/oauth/gitee/callback"));
        UrlEncodedFormEntity urlEncodedFormEntity = new UrlEncodedFormEntity(parameters, "UTF-8");
        //设置请求的参数
        request.setEntity(urlEncodedFormEntity);
        //发送请求
        CloseableHttpResponse response = client.execute(request);
        System.out.println(response.getStatusLine().getStatusCode());
        if (response.getStatusLine().getStatusCode() == 200) {
            HttpEntity entity = response.getEntity();
            String body = EntityUtils.toString(entity, "UTF-8");
            System.out.println(body);
        } else {
            System.out.println(EntityUtils.toString(response.getEntity(), "UTF-8"));
        }
        //关闭资源
        response.close();
        client.close();