/**
     * 1、获取第三方平台access_token
     * 
     * 这种方法不是官方支持的方式，官方提议的事post方式获取
     * 
     * @return
     */
    public static String getToken() {
        String url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=***&secret=****";
        JSONObject jsonObject = WeixinUtil.httpRequest(url, "GET", null);
        System.out.println("获取的第三方平台access_token为：  " + jsonObject.toString());
        return jsonObject.getString("access_token");
    }

这是一个工具类

package com.beiwei.util;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.ConnectException;
import java.net.URL;

import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;

import net.sf.json.JSONObject;

/**
 * 公众平台通用接口工具类
 * 
 * @author YangChao
 * 
 */
public class WeixinUtil {

    /**
     * 发起https请求并获取结果
     * 
     * @param requestUrl
     *            请求地址
     * @param requestMethod
     *            请求方式（GET、POST）
     * @param outputStr
     *            提交的数据
     * @return JSONObject(通过JSONObject.get(key)的方式获取json对象的属性值)
     */
    public static JSONObject httpRequest(String requestUrl, String requestMethod, String outputStr) {
        JSONObject jsonObject = null;
        StringBuffer buffer = new StringBuffer();
        try {
            // 创建SSLContext对象，并使用我们指定的信任管理器初始化
            TrustManager[] tm = { new MyX509TrustManager() };
            SSLContext sslContext = SSLContext.getInstance("SSL", "SunJSSE");
            sslContext.init(null, tm, new java.security.SecureRandom());
            // 从上述SSLContext对象中得到SSLSocketFactory对象
            SSLSocketFactory ssf = sslContext.getSocketFactory();

            URL url = new URL(requestUrl);
            HttpsURLConnection httpUrlConn = (HttpsURLConnection) url.openConnection();
            httpUrlConn.setSSLSocketFactory(ssf);

            httpUrlConn.setDoOutput(true);
            httpUrlConn.setDoInput(true);
            httpUrlConn.setUseCaches(false);
            // 设置请求方式（GET/POST）
            httpUrlConn.setRequestMethod(requestMethod);

            if ("GET".equalsIgnoreCase(requestMethod))
                httpUrlConn.connect();

            // 当有数据需要提交时
            if (null != outputStr) {
                OutputStream outputStream = httpUrlConn.getOutputStream();
                // 注意编码格式，防止中文乱码
                outputStream.write(outputStr.getBytes("UTF-8"));
                outputStream.close();
            }

            // 将返回的输入流转换成字符串
            InputStream inputStream = httpUrlConn.getInputStream();
            InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "utf-8");
            BufferedReader bufferedReader = new BufferedReader(inputStreamReader);

            String str = null;
            while ((str = bufferedReader.readLine()) != null) {
                buffer.append(str);
            }
            bufferedReader.close();
            inputStreamReader.close();
            // 释放资源
            inputStream.close();
            inputStream = null;
            httpUrlConn.disconnect();
            jsonObject = JSONObject.fromObject(buffer.toString());
        } catch (ConnectException ce) {
            ce.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return jsonObject;
    }
}

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