本文实例讲述了微信公众号获取access_token的方法。分享给大家供大家参考，具体如下：
上一版需求做了微信公众号开发，秀了一波操作，也遇到了很多坑。现在把微信公众号一些基本的操作记录一下。
微信公众号获取access_token 官方文档地址
access_token是公众号的全局唯一接口调用凭据，我们和微信服务器进行交互，服务器通过access_token判断我们是谁(哪个公众号服务的请求)。所以 我们在开发过程中服务端拿到的access_token是一定不能显式暴露给外部，否则将导致数据安全问题。别人拿到你的accessToken操作你的公众号。access_token的有效期目前为2个小时，过期需要再次获取。
下面是一种获取access_token方式
1.项目添加httpclient相关依赖，示例使用httpclient请求微信服务器，获取微信返回结果。
org.apache.httpcomponents httpclient4.5.3 org.apache.httpcomponents httpcore4.4.6
2.httpClientUtil类，网上随手找的 试了一下本例的doget方法 没有问题，其他的 暂不考虑
public class HttpClientUtil {
public static String doGet(String url, Map param) {
// 创建Httpclient对象
CloseableHttpClient httpclient = HttpClients.createDefault();
String resultString = "";
CloseableHttpResponse response = null;
try {
// 创建uri
URIBuilder builder = new URIBuilder(url);
if (param != null) {
for (String key : param.keySet()) {
builder.addParameter(key, param.get(key));
}
}
URI uri = builder.build();
// 创建http GET请求
HttpGet httpGet = new HttpGet(uri);
// 执行请求
response = httpclient.execute(httpGet);
// 判断返回状态是否为200
if (response.getStatusLine().getStatusCode() == 200) {
resultString = EntityUtils.toString(response.getEntity(), "UTF-8");
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (response != null) {
response.close();
}
httpclient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return resultString;
}
public static String doGet(String url) {
return doGet(url, null);
}
public static String doPost(String url, Map param) {
// 创建Httpclient对象
CloseableHttpClient httpClient = HttpClients.createDefault();
CloseableHttpResponse response = null;
String resultString = "";
try {
// 创建Http Post请求
HttpPost httpPost = new HttpPost(url);
// 创建参数列表
if (param != null) {
List paramList = new ArrayList<>();
for (String key : param.keySet()) {
paramList.add(new BasicNamevaluePair(key, param.get(key)));
}
// 模拟表单
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(paramList,"utf-8");
httpPost.setEntity(entity);
}
// 执行http请求
response = httpClient.execute(httpPost);
resultString = EntityUtils.toString(response.getEntity(), "utf-8");
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
response.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return resultString;
}
public static String doPost(String url) {
return doPost(url, null);
}
public static String doPostJson(String url, String json) {
// 创建Httpclient对象
CloseableHttpClient httpClient = HttpClients.createDefault();
CloseableHttpResponse response = null;
String resultString = "";
try {
// 创建Http Post请求
HttpPost httpPost = new HttpPost(url);
// 创建请求内容
StringEntity entity = new StringEntity(json, ContentType.APPLICATION_JSON);
httpPost.setEntity(entity);
// 执行http请求
response = httpClient.execute(httpPost);
resultString = EntityUtils.toString(response.getEntity(), "utf-8");
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
response.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return resultString;
}
}
3.第三步就是简单的测试代码了
public class WeChatAccessTokenTest {
public static void main(String[] args) {
Map params = new HashMap<>();
// TODO: 2018/11/16 *号改成真实appid
params.put("appid", "******");
// TODO: 2018/11/16 *号改成真实secret
params.put("secret", "******");
params.put("grant_type", "client_credential");
String response = HttpClientUtil.doGet("https://api.weixin.qq.com/cgi-bin/token", params);
JSonObject accessTokenObject = JSONObject.parseObject(response);
String accessToken = accessTokenObject.getString("access_token");
Long expire = accessTokenObject.getLong("expires_in");
System.out.println(accessToken);
}
}
以上就是微信公众号基础却比较重要的获取access_token操作了！
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