[开发测试]HttpClient的用法

1、Maven依赖

<!-- json转换依赖 -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.78</version>
</dependency>

<!-- 发送http请求依赖 -->
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.13</version>
</dependency>

2、HttpClientUtils工具类

public class HttpClientUtils {

    /**
     * 编码格式。发送编码格式统一用UTF-8
     */
    private static final String ENCODING = "UTF-8";

    /**
     * 设置连接主机超时时间，单位毫秒。
     */
    private static final Integer CONNECT_TIMEOUT = 6000;

    /**
     * 设置连接请求超时时间，单位毫秒。
     */
    private static final Integer CONNECTION_REQUEST_TIMEOUT = 6000;

    /**
     * 请求获取数据的超时时间(即响应时间)，单位毫秒。
     */
    private static final Integer SOCKET_TIMEOUT = 6000;

    /**
     * 发送get请求
     *
     * @param url 链接
     * @return 执行结果
     */
    public static String doGet(String url) throws Exception {
        return doGet(url, null, null);
    }

    /**
     * 发送get请求
     *
     * @param url    链接
     * @param params 请求参数
     * @return 执行结果
     */
    public static String doGet(String url, Map<String, String> params) {
        return doGet(url, null, params);
    }

    /**
     * 发送get请求
     *
     * @param url     链接
     * @param headers 请求头
     * @param params  请求参数
     * @return 执行结果
     */
    public static String doGet(String url, Map<String, String> headers, Map<String, String> params) {
        // 创建client对象
        CloseableHttpClient client = HttpClients.createDefault();
        // 创建response对象
        CloseableHttpResponse response = null;
        // 响应结果
        String result = null;
        try {
            // 创建访问地址，处理请求参数
            URIBuilder uriBuilder = handleParam(url, params);
            // 创建http对象
            HttpGet httpGet = new HttpGet(uriBuilder.build());
            // 处理config参数
            handleConfig(httpGet);
            // 处理请求头
            handleHeader(headers, httpGet);
            // 执行请求
            response = client.execute(httpGet);
            // 响应结果
            result = EntityUtils.toString(response.getEntity(), ENCODING);
        } catch (Exception e) {
            e.getMessage();
        } finally {
            // 释放资源
            release(client, response);
        }
        return result;
    }

    /**
     * 发送post请求
     *
     * @param url     链接
     * @param headers 请求头
     * @return 执行结果
     */
    public static String doPost(String url, Map<String, String> headers) {
        return doPost(url, headers, null, null);
    }

    /**
     * 发送post请求
     *
     * @param url     链接
     * @param headers 请求头
     * @param params  请求参数
     * @return 执行结果
     */
    public static String doPost(String url, Map<String, String> headers, Map<String, String> params) {
        return doPost(url, headers, params, null);
    }

    /**
     * 发送post请求
     *
     * @param url     链接
     * @param headers 请求头
     * @param body    请求体
     * @return 执行结果
     */
    public static String doPost(String url, Map<String, String> headers, String body) {
        return doPost(url, headers, null, body);
    }

    /**
     * 发送post请求
     *
     * @param url     链接
     * @param headers 请求头
     * @param params  请求参数
     * @param body    请求体
     * @return 执行结果
     */
    public static String doPost(String url, Map<String, String> headers, Map<String, String> params, String body) {
        // 创建client对象
        CloseableHttpClient client = HttpClients.createDefault();
        // 创建response对象
        CloseableHttpResponse response = null;
        // 响应结果
        String result = null;
        try {
            // 创建访问地址，处理请求参数
            URIBuilder uriBuilder = handleParam(url, params);
            // 创建http对象
            HttpPost httpPost = new HttpPost(uriBuilder.build());
            // 处理config参数
            handleConfig(httpPost);
            // 处理请求头
            handleHeader(headers, httpPost);
            // 处理请求体
            handleBody(body, httpPost);
            // 执行请求
            response = client.execute(httpPost);
            // 响应结果
            result = EntityUtils.toString(response.getEntity(), ENCODING);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            release(client, response);
        }
        return result;
    }

    /**
     * 发送delete请求
     *
     * @param url 链接
     * @return 执行结果
     */
    public static String doDelete(String url) throws IOException {
        return doDelete(url, null, null);
    }

    /**
     * 发送delete请求
     *
     * @param url     链接
     * @param headers 请求头
     * @param params  请求参数
     * @return 执行结果
     */
    public static String doDelete(String url, Map<String, String> headers, Map<String, String> params) {
        // 创建client对象
        CloseableHttpClient client = HttpClients.createDefault();
        // 创建response对象
        CloseableHttpResponse response = null;
        // 响应结果
        String result = null;
        try {
            // 创建访问地址，处理请求参数
            URIBuilder uriBuilder = handleParam(url, params);
            // 创建http对象
            HttpDelete httpDelete = new HttpDelete(uriBuilder.build());
            // 处理config参数
            handleConfig(httpDelete);
            // 处理请求头
            handleHeader(headers, httpDelete);
            // 执行请求
            response = client.execute(httpDelete);
            // 响应对象
            result = EntityUtils.toString(response.getEntity(), ENCODING);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            release(client, response);
        }
        return result;
    }

    /**
     * 处理请求参数
     *
     * @param url    链接
     * @param params 请求参数
     * @return 执行结果
     */
    private static URIBuilder handleParam(String url, Map<String, String> params) throws URISyntaxException {
        URIBuilder uriBuilder = new URIBuilder(url);
        if (params != null) {
            Set<Map.Entry<String, String>> entrySet = params.entrySet();
            for (Map.Entry<String, String> entry : entrySet) {
                uriBuilder.setParameter(entry.getKey(), entry.getValue());
            }
        }
        return uriBuilder;
    }

    /**
     * 处理config设置
     *
     * @param httpMethod 方法对象
     */
    private static void handleConfig(HttpRequestBase httpMethod) {
        if (httpMethod != null) {
            RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(CONNECT_TIMEOUT).setConnectionRequestTimeout(CONNECTION_REQUEST_TIMEOUT).setSocketTimeout(SOCKET_TIMEOUT).build();
            httpMethod.setConfig(requestConfig);
        }
    }

    /**
     * 处理请求头
     *
     * @param params     请求参数
     * @param httpMethod 方法对象
     */
    private static void handleHeader(Map<String, String> params, HttpRequestBase httpMethod) {
        if (params != null) {
            Set<Map.Entry<String, String>> entrySet = params.entrySet();
            for (Map.Entry<String, String> entry : entrySet) {
                httpMethod.setHeader(entry.getKey(), entry.getValue());
            }
        }
    }

    /**
     * 处理请求体
     *
     * @param body     请求体
     * @param httpPost 方法对象
     */
    private static void handleBody(String body, HttpPost httpPost) {
        if (body != null) {
            httpPost.setEntity(new StringEntity(body, ENCODING));
        }
    }

    /**
     * 释放资源
     *
     * @param client   客户端连接对象
     * @param response 响应对象
     */
    private static void release(CloseableHttpClient client, CloseableHttpResponse response) {
        if (client != null) {
            try {
                client.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        if (response != null) {
            try {
                response.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

3、Get请求方式举例

代码：

public class Test {
    public static void main(String[] args) throws Exception {
        System.out.println(HttpClientUtils.doGet("http://www.baidu.com"));
    }
}

结果：

<!DOCTYPE html><!--STATUS OK--><html> <head><meta http-equiv=content-type content=text/html;charset=utf-8><meta http-equiv=X-UA-Compatible content=IE=Edge><meta content=always name=referrer><link rel=stylesheet type=text/css href=http://s1.bdstatic.com/r/www/cache/bdorz/baidu.min.css><title>百度一下，你就知道</title></head> <body link=#0000cc> <div id=wrapper> <div id=head> <div class=head_wrapper> <div class=s_form> <div class=s_form_wrapper> <div id=lg> <img hidefocus=true src=//www.baidu.com/img/bd_logo1.png width=270 height=129> </div> <form id=form name=f action=//www.baidu.com/s class=fm> <input type=hidden name=bdorz_come value=1> <input type=hidden name=ie value=utf-8> <input type=hidden name=f value=8> <input type=hidden name=rsv_bp value=1> <input type=hidden name=rsv_idx value=1> <input type=hidden name=tn value=baidu><span class="bg s_ipt_wr"><input id=kw name=wd class=s_ipt value maxlength=255 autocomplete=off autofocus></span><span class="bg s_btn_wr"><input type=submit id=su value=百度一下 class="bg s_btn"></span> </form> </div> </div> <div id=u1> <a href=http://news.baidu.com name=tj_trnews class=mnav>新闻</a> <a href=http://www.hao123.com name=tj_trhao123 class=mnav>hao123</a> <a href=http://map.baidu.com name=tj_trmap class=mnav>地图</a> <a href=http://v.baidu.com name=tj_trvideo class=mnav>视频</a> <a href=http://tieba.baidu.com name=tj_trtieba class=mnav>贴吧</a> <noscript> <a href=http://www.baidu.com/bdorz/login.gif?login&amp;tpl=mn&amp;u=http%3A%2F%2Fwww.baidu.com%2f%3fbdorz_come%3d1 name=tj_login class=lb>登录</a> </noscript> <script>document.write('<a href="http://www.baidu.com/bdorz/login.gif?login&tpl=mn&u='+ encodeURIComponent(window.location.href+ (window.location.search === "" ? "?" : "&")+ "bdorz_come=1")+ '" name="tj_login" class="lb">登录</a>');</script> <a href=//www.baidu.com/more/ name=tj_briicon class=bri style="display: block;">更多产品</a> </div> </div> </div> <div id=ftCon> <div id=ftConw> <p id=lh> <a href=http://home.baidu.com>关于百度</a> <a href=http://ir.baidu.com>About Baidu</a> </p> <p id=cp>&copy;2017&nbsp;Baidu&nbsp;<a href=http://www.baidu.com/duty/>使用百度前必读</a>&nbsp; <a href=http://jianyi.baidu.com/ class=cp-feedback>意见反馈</a>&nbsp;京ICP证030173号&nbsp; <img src=//www.baidu.com/img/gs.gif> </p> </div> </div> </div> </body> </html>

4、POST请求方式举例

例1：获取token

代码

public class Test {
    public static void main(String[] args) {
        System.out.println("token：" + doPost("接口地址", "root", "123456", "default"));
    }

    /**
     * 测试post请求方式
     * @author 明快de玄米61
     * @date   2021/9/6 23:12
     * @param  apiUrl 接口地址
     * @param  username 用户名
     * @param  password 密码
     * @param  tenantUrl 租户标识
     * @return
     **/
    private static String doPost(String apiUrl, String username, String password, String tenantUrl) {
        String idToken = null;
        // 设置headers
        Map<String, String> headers = new HashMap<>();
        // 设置传送的内容类型是json格式
        headers.put("Content-Type", "application/json;charset=utf-8");
        // 接收的内容类型也是json格式
        headers.put("Accept", "application/json;charset=utf-8");
        // 准备数据
        JSONObject json = new JSONObject();
        json.put("username", username);
        json.put("password", DigestUtils.md5Hex(password));
        json.put("tenantUrl", tenantUrl);
        // 获取结果
        String result = HttpClientUtils.doPost(apiUrl, headers, json.toJSONString());
        // 处理返回的内容
        if (result != null && !"".equals(result.trim())) {
            JSONObject rjo = JSONObject.parseObject(result, Feature.OrderedField);
            if (rjo != null && rjo.containsKey("retCode")) {
                int retCode = rjo.getInteger("retCode");
                if (retCode == 0 && rjo.containsKey("data")) {
                    JSONObject data = rjo.getJSONObject("data");
                    if (null != data && data.containsKey("idToken")) {
                        // 获取最终想要的数据
                        idToken = data.getString("idToken");
                    }
                }
            }
        }
        return idToken;
    }
}

结果

token：853b7c87-c16f-4e3b-96c4-9701fe3448ab

接口文档

Postman访问示例

5、拓展

1、http协议切换为https协议（视情况使用，也不是所有https协议都要用这种方式）

如果http协议变成了https协议，我们需要更换HttpCloseableHttpClient的获取方式，我们先创建一个DefaultSSLUtils工具类，如下：

public class DefaultSSLUtils extends DefaultHttpClient {
    public DefaultSSLUtils() throws Exception {
        super();
        SSLContext ctx = SSLContext.getInstance("TLS");
        X509TrustManager tm = new X509TrustManager() {
            @Override
            public void checkClientTrusted(X509Certificate[] chain,
                                           String authType) throws CertificateException {
            }

            @Override
            public void checkServerTrusted(X509Certificate[] chain,
                                           String authType) throws CertificateException {
            }

            @Override
            public X509Certificate[] getAcceptedIssuers() {
                return null;
            }
        };
        ctx.init(null, new TrustManager[]{tm}, null);
        SSLSocketFactory ssf = new SSLSocketFactory(ctx, SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);
        ClientConnectionManager ccm = this.getConnectionManager();
        SchemeRegistry sr = ccm.getSchemeRegistry();
        sr.register(new Scheme("https", 443, ssf));
    }
}

在获取HttpCloseableHttpClient对象的时候直接使用如下代码：

CloseableHttpClient httpclient = new DefaultSSLUtils();