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 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 postCapture(String requestData) throws Exception{ HashMap 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; } } 原文地址：
