【微信公众号】获取获取微信的access_token

什么是access_token?

公众平台的API调用所需的access_token的使用及生成方式说明：

2、目前Access_token的有效期通过返回的expire_in来传达，目前是7200秒之内的值。中控服务器需要根据这个有效时间提前去刷新新access_token。在刷新过程中，中控服务器可对外继续输出的老access_token，此时公众平台后台会保证在5分钟内，新老access_token都可用，这保证了第三方业务的平滑过渡；

3、Access_token的有效时间可能会在未来有调整，所以中控服务器不仅需要内部定时主动刷新，还需要提供被动刷新access_token的接口，这样便于业务服务器在API调用获知access_token已超时的情况下，可以触发access_token的刷新流程。

首先申请开发者身份，填写基本信息后，在基本配置中进行服务器的配置:

由于我这时测试开发者，我们就直接将其写死

文档看完后，我们接下来进行测试:

判断签名是否一致:

/**
     * 判断签名是否一致
     * @param signature
     * @param timestamp
     * @param nonce
     * @param token
     * @return
     */
    @Override
    public boolean verifyInfo(String signature, String timestamp, String nonce, String token) {
        TreeSet<String> set = new TreeSet<String>();
        set.add(token);
        set.add(timestamp);
        set.add(nonce);
        StringBuilder sb = new StringBuilder();
        for (String item : set) {
            sb.append(item);
        }
        String sign = DigestUtils.sha1Hex(sb.toString());
        return signature.equalsIgnoreCase(sign);
    }

/**
 * @author evan_qb
 * @date 2018/8/13 14:54
 * HttpClient工具
 */
public class HttpClientUtil {
    /**
     * POST请求
     * @param url
     * @param jsonStr
     * @return
     */
    public static String sendpostJson(String url, String jsonStr){
        String result = null;
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpPost post = new HttpPost(url);
        CloseableHttpResponse response = null;
        try {
            post.setEntity(new ByteArrayEntity(jsonStr.getBytes("UTF-8")));
            response = httpClient.execute(post);
            if (response != null && response.getStatusLine().getStatusCode() == 200){
                HttpEntity entity = response.getEntity();
                result = JsonMapper.object2String(entity);
            }
        }catch (Exception e){

        }finally {
            try {
                httpClient.close();
                if (response != null){
                    response.close();
                }
            } catch (IOException e) {

            }
        }
        return null;
    }

    /**
     * GET请求
     * @param url
     * @return
     */
    public static String sendGet(String url,Map<String,String> map){
        String result = null;
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpGet get = new HttpGet(url);
        CloseableHttpResponse response = null;
        try{
            //创建uri
            URIBuilder builder = new URIBuilder(url);
            if (map != null){
                for (String key: map.keySet()){
                    builder.addParameter(key,map.get(key));
                }
            }
            URI uri = builder.build();
            //创建get请求
            HttpGet httpGet = new HttpGet(uri);
            //执行请求
            response =  httpClient.execute(httpGet);
            if (response.getStatusLine().getStatusCode() == 200){
                result = EntityUtils.toString(response.getEntity(),"UTF-8");

            }

        }catch (Exception e){

        }finally {
            try {
                httpClient.close();
                if (response != null){
                     response.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }

        }
        return result;
    }
}

接着我们进行输入地址获取我们的access_token，就能接着下面的开发了