获取access_token

import java.io.IOException;

import org.apache.http.HttpEntity;

import org.apache.http.HttpResponse;

import org.apache.http.client.ClientProtocolException;

import org.apache.http.client.methods.HttpGet;

import org.apache.http.client.methods.HttpPost;

import org.apache.http.entity.StringEntity;

import org.apache.http.impl.client.DefaultHttpClient;

import org.apache.http.util.EntityUtils;

import net.sf.json.JSONObject;

public class WeiXinUtil {

    //从微信后台拿到APPID和APPSECRET 

    private static final String APPID = "APPID";

    private static final String APPSECRET = "APPSECRET";

    private static final String ACCESS_TOKEN_URL = "https://api.weixin.qq.com/cgi-bin/token?    grant_type=client_credential&appid=APPID&secret=APPSECRET";

    /**

     * 编写Get请求的方法。但没有参数传递的时候，可以使用Get请求

     * 

     * @param url 需要请求的URL

     * @return 将请求URL后返回的数据，转为JSON格式，并return

     */

    public static JSONObject doGetStr(String url) throws ClientProtocolException, IOException {

        DefaultHttpClient client = new DefaultHttpClient();//获取DefaultHttpClient请求

        HttpGet httpGet = new HttpGet(url);//HttpGet将使用Get方式发送请求URL

        JSONObject jsonObject = null;

        HttpResponse response = client.execute(httpGet);//使用HttpResponse接收client执行httpGet的结果

        HttpEntity entity = response.getEntity();//从response中获取结果，类型为HttpEntity

        if(entity != null){

            String result = EntityUtils.toString(entity,"UTF-8");//HttpEntity转为字符串类型

            jsonObject = JSONObject.fromObject(result);//字符串类型转为JSON类型

        }

        return jsonObject;

    }

    

    /**

     * 编写Post请求的方法。当我们需要参数传递的时候，可以使用Post请求

     * 

     * @param url 需要请求的URL

     * @param outStr  需要传递的参数

     * @return 将请求URL后返回的数据，转为JSON格式，并return

     */

    public static JSONObject doPostStr(String url,String outStr) throws ClientProtocolException, IOException {

        DefaultHttpClient client = new DefaultHttpClient();//获取DefaultHttpClient请求

        HttpPost httpost = new HttpPost(url);//HttpPost将使用Get方式发送请求URL

        JSONObject jsonObject = null;

        httpost.setEntity(new StringEntity(outStr,"UTF-8"));//使用setEntity方法，将我们传进来的参数放入请求中

        HttpResponse response = client.execute(httpost);//使用HttpResponse接收client执行httpost的结果

        String result = EntityUtils.toString(response.getEntity(),"UTF-8");//HttpEntity转为字符串类型

        jsonObject = JSONObject.fromObject(result);//字符串类型转为JSON类型

        return jsonObject;

    }

    

    /**

     * 获取AccessToken

     * @return 返回拿到的access_token及有效期

     */

    public static String getAccessToken() throws ClientProtocolException, IOException{

        String url = ACCESS_TOKEN_URL.replace("APPID", APPID).replace("APPSECRET", APPSECRET);//将URL中的两个参数替换掉

        JSONObject jsonObject = doGetStr(url);//使用刚刚写的doGet方法接收结果

        String token = "";

        if(jsonObject!=null){ //如果返回不为空，将返回结果封装进AccessToken实体类

        token = (jsonObject.getString("access_token"));//取出access_token

//            token.setExpiresIn(jsonObject.getInt("expires_in"));//取出access_token的有效期  我这边先注释掉

        }

        return token;

    }

    

    

    public static void main(String[] args) throws ClientProtocolException, IOException {
String string = WeiXinUtil.getAccessToken();
System.out.println(string);
}

}