java后端获取微信的openId

-- 首先说明一下  code 只能用一次并且有使用期限，好像是五分钟，通过前端传过来code和后台配置的appSecret和appid完成获取openid的操作。

public class WxUtil {
    private static final String openIdUrl = "https://api.weixin.qq.com/sns/jscode2session?appid=%s&secret=%s&js_code=%s&grant_type=authorization_code";
    public static OpenIdAndSessionKey getOpenId(String appId, String secret, String code) {
        OpenIdAndSessionKey openIdAndSessionKey =new OpenIdAndSessionKey();
        try (CloseableHttpClient httpClient = HttpClientBuilder.create().build()) {
            String requestUrl = String.format(openIdUrl, appId, secret, code);
            HttpGet httpGet = new HttpGet(requestUrl);
            HttpEntity responseEntity = httpClient.execute(httpGet).getEntity();
            if (responseEntity != null) {
                String responseStr = EntityUtils.toString(responseEntity);
                if (responseStr.contains("openid")) {
                    WxResponse wxResponse = JsonUtil.toJsonObject(responseStr, WxResponse.class);
                    openIdAndSessionKey.setOpenId(wxResponse.getOpenid());
                    openIdAndSessionKey.setSessionKey(wxResponse.getSession_key());
                    return openIdAndSessionKey;
                }
            }
        }catch (IOException e) {
            logger.error(e.getMessage(), e);
        }
        return null;
    }
}
这里我用了一个openIdAndSessionKey类来接受微信后台返回给我的openId和SessionKey，如果想获取手机号码那就会用到这个key。获取手机号码的操作在我另外一篇博客里有写。

maven 依赖

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
</dependency>