java爬虫-0020，httpclient获取源码

╰+攻爆jí腚メ 2022-05-09 07:56 217阅读 0赞

项目地址：[https://github.com/wenrongyao/java\_crawler][https_github.com_wenrongyao_java_crawler]

1、导入httpclient依赖

<dependency>
                <groupId>org.apache.httpcomponents</groupId>
                <artifactId>httpclient</artifactId>
                <version>4.3</version>
            </dependency>
            <dependency>
                <groupId>org.apache.httpcomponents</groupId>
                <artifactId>httpclient-cache</artifactId>
                <version>4.3</version>
            </dependency>
            <dependency>
                <groupId>org.apache.httpcomponents</groupId>
                <artifactId>httpmime</artifactId>
                <version>4.3</version>
            </dependency>

2、封装请求对象

/**
     * Created by rongyaowen on 2018/10/4.
     * 请求封装，get请求，post请求。
     */
    public class Request {
        private static CloseableHttpClient closeableHttpClient = HttpClientBuilder.create().build();
    
        /**
         * get 请求
         *
         * @param url
         * @param headerParams 请求头
         * @return
         */
        public static Map<String, Object> get(String url, Map<String, Object> headerParams) {
            HttpGet httpGet = new HttpGet(url);
            Map<String, Object> logMap = new HashMap<>();
            logMap.put("请求链接", url);
            return response(httpGet, headerParams, logMap);
        }
    
        /**
         * post 请求
         *
         * @param url
         * @param headerParams  请求头
         * @param requestParams 请求数据
         * @return
         */
        public static Map<String, Object> post(String url, Map<String, Object> headerParams, Map<String, Object> requestParams) {
            HttpPost httpPost = new HttpPost(url);
            StringEntity entity = null;
            try {
                String requestParamsStr = null;
                if (!requestParams.isEmpty() && !StringUtils.isEmpty(requestParamsStr = requestParams.get(P.REQUEST.REQUEST_PARAMS).toString())) {
                    entity = new StringEntity(requestParamsStr);
                }
                String contentTypeStr = null;
                if (!requestParams.isEmpty() && !StringUtils.isEmpty(contentTypeStr = requestParams.get(P.REQUEST.CONTENT_TYPE).toString())) {
                    // 表单格式数据
                    entity.setContentType(contentTypeStr);
                }
                httpPost.setEntity(entity);
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }
            Map<String, Object> logMap = new HashMap<>();
            logMap.put("亲求链接", url);
            logMap.put("请求参数", requestParams);
    
            return response(httpPost, headerParams, logMap);
        }
    
        /**
         * 请求
         *
         * @param httpRequestBase
         * @param headerParams    请求头
         * @param logMap          日志map
         * @return
         */
        private static Map<String, Object> response(HttpRequestBase httpRequestBase, Map<String, Object> headerParams, Map<String, Object> logMap) {
            Map<String, Object> resMap = new HashMap<>();
            RequestConfig config = RequestConfig.custom().setConnectionRequestTimeout(5000).setConnectTimeout(5000)
                    .setSocketTimeout(5000).build();
            httpRequestBase.setConfig(config);
            // 拼装请求头
            if (!headerParams.isEmpty()) {
                for (Map.Entry<String, Object> entry : headerParams.entrySet()) {
                    httpRequestBase.addHeader(entry.getKey(), entry.getValue().toString());
                }
            }
    
            try {
                HttpResponse httpResponse = closeableHttpClient.execute(httpRequestBase);
                // 状态码
                int statusCode = httpResponse.getStatusLine().getStatusCode();
                logMap.put("请求头", headerParams);
                logMap.put("状态码", statusCode);
                logMap.put("请求方法", httpRequestBase.getMethod());
                LogUtil.debug(LogUtil.mapToStr(logMap));
    
                // 返回响应body数据
                HttpEntity entity = httpResponse.getEntity();
                String resBody = EntityUtils.toString(entity, "utf-8");
                // 响应头
                Header[] headers = httpResponse.getAllHeaders();
    
                // 组装响应
                resMap.put(P.REQUEST.RES_BODY, resBody);
                resMap.put(P.REQUEST.HEADERS, headers);
            } catch (IOException e) {
                e.printStackTrace();
            }
            return resMap;
        }
    
        /**
         * 获取请求流
         *
         * @param url
         * @param headerParams
         * @return
         */
        public static InputStream getAuthCode(String url, Map<String, Object> headerParams) {
            RequestConfig config = RequestConfig.custom().setConnectionRequestTimeout(5000).setConnectTimeout(5000)
                    .setSocketTimeout(5000).build();
            HttpGet httpGet = new HttpGet(url);
            httpGet.setConfig(config);
            // 拼装请求头
            if (!headerParams.isEmpty()) {
                for (Map.Entry<String, Object> entry : headerParams.entrySet()) {
                    httpGet.addHeader(entry.getKey(), entry.getValue().toString());
                }
            }
            HttpResponse httpResponse = null;
            try {
                httpResponse = closeableHttpClient.execute(httpGet);
                int statusCode = httpResponse.getStatusLine().getStatusCode();
                Map<String, Object> logMap = new HashMap<>();
                logMap.put("请求链接", url);
                logMap.put("请求头", headerParams);
                logMap.put("请求方法", httpGet.getMethod());
                logMap.put("请求状态", statusCode);
                LogUtil.debug(LogUtil.mapToStr(logMap));
    
                if (statusCode == HttpStatus.SC_OK) {
                    HttpEntity entity = httpResponse.getEntity();
                    return entity.getContent();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        }
    }

3、获取某瓣网未登录主页内容

首页在谷歌的开发者工具中，拿到User-Agent的头信息（没有这个信息，会被服务器判定为爬虫）

![70][]

4、模拟发送请求获取主页内容

/**
         * 第一个爬虫程序，获取源码，注意需要带上User_Agetn
         */
        @Test
        public void crawlerClient_01() {
            String url = "https://www.douban.com";
            Map<String, Object> headerParams = new HashMap<>();
            headerParams.put(P.REQUEST.USER_AGENT, P.USER_AGENT);
            Map<String, Object> resMap = Request.get(url, headerParams);
            System.out.println(resMap.get(P.REQUEST.RES_BODY));
        }

5、效果展示

![70 1][]

[https_github.com_wenrongyao_java_crawler]: https://github.com/wenrongyao/java_crawler
[70]: /images/20220509/35b02e5b9f2b446786b9f4b8c2e0d1a5.png
[70 1]: /images/20220509/3c239736d8384fa282dce3787b393ef1.png