爬虫记录（3）——模拟登录获取cookie，访问私信页面

继上一篇博文 爬虫记录（2）——简单爬取一个页面的图片并保存 ，今天我们通过httpclient模拟表单登录开源中国，获取cookie，然后通过cookie访问个人私信页面。

1、准备工作

模拟表单登录，首先需要知道登录的url，以及登录表单的字段。这里我们图一中故意输入一个错误的用户名和密码，然后通过查看图二中的network中，发现登录的url是https://www.oschina.net/action/user/hash_login?from=，字段是 账号为email ， 密码是pwd
而且密码通过相应的处理，我们先不管他，反正输入的是正确的密码，直接拿图中字符串即可。

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图一

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图二

2、修改相应的爬虫工具类CrawlerUtils

增加post方法，插入消息体。也修改相应的get方法，增加插入cookie的方法。

package com.dyw.crawler.util;import org.apache.commons.httpclient.Cookie;import org.apache.commons.httpclient.HttpClient;import org.apache.commons.httpclient.HttpMethod;import org.apache.commons.httpclient.HttpStatus;import org.apache.commons.httpclient.NameValuePair;import org.apache.commons.httpclient.cookie.CookiePolicy;import org.apache.commons.httpclient.methods.GetMethod;import org.apache.commons.httpclient.methods.PostMethod;import java.io.IOException;import java.io.InputStream;import java.util.Map;/** * 爬虫工具类 * Created by dyw on 2017/9/1. */public class CrawlerUtils {    /**     * http请求设置消息头     *     * @param httpMethod http请求方法     */    private static void setHead(HttpMethod httpMethod) {        setHead(httpMethod, null);    }    /**     * http请求设置自定义消息头     *     * @param httpMethod http请求方法     * @param map        消息头     */    private static void setHead(HttpMethod httpMethod, Map<String, String> map) {        //判断是否传入自定义消息头        if (null != map && map.size() > 0) {            map.keySet().forEach(key -> httpMethod.setRequestHeader(key, map.get(key)));        }        //公共消息头(不同的网站消息头内容不一致)        httpMethod.setRequestHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Safari/537.36");        httpMethod.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");        httpMethod.setRequestHeader("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");    }    /**     * post方法设置登陆用户信息     *     * @param postMethod post方法     * @param loginInfo  消息体     */    private static void setBody(PostMethod postMethod, NameValuePair[] loginInfo) {        postMethod.setRequestBody(loginInfo);    }    /**     * 获取html内容转成string输出（get方法）     *     * @param url url链接     * @return 整个网页转成String字符串     */    public static String get(String url) throws Exception {        return get(url, null);    }    /**     * 获取html内容转成string输出（get方法）有自带的消息头     *     * @param url url链接     * @param map 消息头内容     * @return 整个网页转成String字符串     */    public static String get(String url, Map<String, String> map) throws Exception {        String html = null;        HttpClient httpClient = new HttpClient();        HttpMethod httpMethod = new GetMethod(url);        setHead(httpMethod, map);        int status = httpClient.executeMethod(httpMethod);        if (status == HttpStatus.SC_OK) {            html = httpMethod.getResponseBodyAsString();        }        return html;    }    /**     * 登陆方法，获取cookie（post方法）     *     * @param url url链接     * @return cookie     */    public static String post(String url, NameValuePair[] loginInfo) throws Exception {        HttpClient httpClient = new HttpClient();        // 模拟登陆，按实际服务器端要求选用Post请求方式        PostMethod postMethod = new PostMethod(url);        setHead(postMethod);        setBody(postMethod, loginInfo);        httpClient.getParams().setCookiePolicy(CookiePolicy.BROWSER_COMPATIBILITY);        httpClient.executeMethod(postMethod);        // 获得登陆后的 Cookie        Cookie[] cookies = httpClient.getState().getCookies();        StringBuffer cookie = new StringBuffer();        for (Cookie c : cookies) {            cookie.append(c.toString() + ";");        }        return cookie.toString();    }    /**     * 获取文件流（get方法）     *     * @param urlStr url地址     * @return InputStream     */    public static InputStream downLoadFromUrl(String urlStr) throws IOException {        //通过httpclient来代替urlConnection//        HttpHost proxy=new HttpHost("116.226.217.54", 9999);        HttpClient httpClient = new HttpClient();        HttpMethod httpMethod = new GetMethod(urlStr);//        HostConfiguration hostConfiguration = new HostConfiguration();//        hostConfiguration.setHost("116.226.217.54", 9999);//        httpClient.setHostConfiguration(hostConfiguration);        setHead(httpMethod);        int status = httpClient.executeMethod(httpMethod);        InputStream responseBodyAsStream = null;        if (status == HttpStatus.SC_OK) {            responseBodyAsStream = httpMethod.getResponseBodyAsStream();        }        return responseBodyAsStream;    }}

3、main主方法

package com.dyw.crawler.project;import com.dyw.crawler.util.CrawlerUtils;import org.apache.commons.httpclient.NameValuePair;import java.util.HashMap;import java.util.Map;/** * 模拟登陆 * Created by dyw on 2017/9/5. */public class Project2 {    public static void main(String[] args) {        // 1   Url 开源中国网站登录url        String loginUrl = "https://www.oschina.net/action/user/hash_login?from=";        //个人私信网站，登录才能进入        String dataUrl = "https://my.oschina.net/u/3673710/admin/inbox";        // 设置登陆时要求的信息，用户名和密码        NameValuePair[] loginInfo = {new NameValuePair("email", "账号"),                new NameValuePair("pwd", "密码")};        try {            String cookie = CrawlerUtils.post(loginUrl, loginInfo);            Map<String, String> map = new HashMap<>();            map.put("Cookie", cookie);            String html = CrawlerUtils.get(dataUrl, map);            System.out.println(html);        } catch (Exception e) {            e.printStackTrace();        }    }}

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这样我们就能获取到私信网站内容。

具体代码我上传在github上，需要完整代码的可以自己下载 https://github.com/dingyinwu81/crawler

如果有什么代码修改的建议，请给我留言呗！ ☺☺☺