最近弄爬虫，遇到的一个问题就是如何使用post方法模拟登陆爬取网页。下面是极简版的代码：

import java.io.BufferedReader;

import java.io.InputStreamReader;

import java.io.OutputStreamWriter;

import java.io.PrintWriter;

import java.net.HttpURLConnection;

import java.net.URL;

import java.util.HashMap;

public class test {

	//post请求地址

	private static final String POST_URL = "";

	//模拟谷歌浏览器请求

	private static final String USER_AGENT = "";

	//用账号登录某网站后 请求POST_URL链接获取cookie

	private static final String COOKIE = "";

	//用账号登录某网站后 请求POST_URL链接获取数据包

	private static final String REQUEST_DATA =  "";

	public static void main(String[] args) throws Exception {

		HashMap<String, String> map = postCapture(REQUEST_DATA);

		String responseCode = map.get("responseCode");

		String value = map.get("value");

		while(!responseCode.equals("200")){

			map =  postCapture(REQUEST_DATA);

			responseCode = map.get("responseCode");

			value = map.get("value");

		}

		//打印爬取结果

		System.out.println(value);

	}

	private static HashMap<String, String> postCapture(String requestData) throws Exception{

		HashMap<String, String> map = new HashMap<>();

		URL url = new URL(POST_URL);

		HttpURLConnection httpConn = (HttpURLConnection) url.openConnection();

		httpConn.setDoInput(true); // 设置输入流采用字节流

		httpConn.setDoOutput(true); // 设置输出流采用字节流

		httpConn.setUseCaches(false); //设置缓存

		httpConn.setRequestMethod("POST");//POST请求

		httpConn.setRequestProperty("User-Agent", USER_AGENT);

		httpConn.setRequestProperty("Cookie", COOKIE);

		PrintWriter out = new PrintWriter(new OutputStreamWriter(httpConn.getOutputStream(), "UTF-8"));

		out.println(requestData);

		out.close();

		int responseCode = httpConn.getResponseCode();

		StringBuffer buffer = new StringBuffer();

		if (responseCode == 200) {

			BufferedReader reader = new BufferedReader(new InputStreamReader(httpConn.getInputStream(), "UTF-8"));

			String line = null;

			while ((line = reader.readLine()) != null) {

				buffer.append(line);

			}

			reader.close();

			httpConn.disconnect();

		}

		map.put("responseCode", new Integer(responseCode).toString());

		map.put("value", buffer.toString());

		return map;

	}

}

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原文地址：

http://wangxin123.com/2016/12/19/使用Post方法模拟登陆爬取网页/