java模拟浏览器请求HttpUtils，可秒杀京东优惠券

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package com.boot.utils;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Map;
import java.util.Map.Entry;

/**
 * @Auther: zyx.
 * @Date: 2018/10/24 8:47
 */
public class HttpUtils {

  public static String http(String url, Map params, String contentType, String token) {
    URL u = null;
    HttpURLConnection con = null;
    // 构建请求参数
    StringBuffer sb = new StringBuffer();
    if (params != null) {
      for (Entry e : params.entrySet()) {
        sb.append(e.getKey());
        sb.append("=");
        sb.append(e.getValue());
        sb.append("&");
      }
      sb.substring(0, sb.length() - 1);
    }

    // 尝试发送请求
    try {
      u = new URL(url);
      con = (HttpURLConnection) u.openConnection();
      //// POST 只能为大写，严格限制，post会不识别
      con.setRequestMethod("POST");
      con.setDoOutput(true);
      con.setDoInput(true);
      con.setUseCaches(false);
      con.setRequestProperty("Content-Type", contentType);
      con.setRequestProperty("cookie", token);
      OutputStreamWriter osw = new OutputStreamWriter(con.getOutputStream(), "UTF-8");
      osw.write(sb.toString());
      osw.flush();
      osw.close();
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      if (con != null) {
        con.disconnect();
      }
    }

    // 读取返回内容
    StringBuffer buffer = new StringBuffer();
    try {
      //一定要有返回值，否则无法把请求发送给server端。
      BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream(), "UTF-8"));
      String temp;
      while ((temp = br.readLine()) != null) {
        buffer.append(temp);
        buffer.append("\n");
      }
    } catch (Exception e) {
      e.printStackTrace();
    }

    return buffer.toString();
  }

}

转载于:https://my.oschina.net/zhangyaxin/blog/2251839