本文例項講述了微信公眾號獲取access_token的方法。分享給大家供大家參考，具體如下：

上一版需求做了微信公眾號開發，秀了一波操作，也遇到了很多坑。現在把微信公眾號一些基本的操作記錄一下。

微信公眾號獲取access_token 官方文件地址

access_token是公眾號的全域性唯一介面呼叫憑據，我們和微信伺服器進行互動，伺服器通過access_token判斷我們是誰(哪個公眾號服務的請求)。所以 我們在開發過程中服務端拿到的access_token是一定不能顯式暴露給外部，否則將導致資料安全問題。別人拿到你的accessToken操作你的公眾號。access_token的有效期目前為2個小時，過期需要再次獲取。

下面是一種獲取access_token方式

1.專案新增httpclient相關依賴，示例使用httpclient請求微信伺服器，獲取微信返回結果。

<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
  <dependency>
   <groupId>org.apache.httpcomponents</groupId>
   <artifactId>httpclient</artifactId>
   <version>4.5.3</version>
  </dependency>
  <!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpcore -->
  <dependency>
   <groupId>org.apache.httpcomponents</groupId>
   <artifactId>httpcore</artifactId>
   <version>4.4.6</version>
  </dependency>

2.httpClientUtil類，網上隨手找的 試了一下本例的doget方法 沒有問題，其他的 暫不考慮

public class HttpClientUtil {
  public static String doGet(String url,Map<String,String> param) {
    // 建立Httpclient物件
    CloseableHttpClient httpclient = HttpClients.createDefault();
    String resultString = "";
    CloseableHttpResponse response = null;
    try {
      // 建立uri
      URIBuilder builder = new URIBuilder(url);
      if (param != null) {
        for (String key : param.keySet()) {
          builder.addParameter(key,param.get(key));
        }
      }
      URI uri = builder.build();
      // 建立http GET請求
      HttpGet httpGet = new HttpGet(uri);
      // 執行請求
      response = httpclient.execute(httpGet);
      // 判斷返回狀態是否為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,String> param) {
    // 建立Httpclient物件
    CloseableHttpClient httpClient = HttpClients.createDefault();
    CloseableHttpResponse response = null;
    String resultString = "";
    try {
      // 建立Http Post請求
      HttpPost httpPost = new HttpPost(url);
      // 建立引數列表
      if (param != null) {
        List<NameValuePair> paramList = new ArrayList<>();
        for (String key : param.keySet()) {
          paramList.add(new BasicNameValuePair(key,param.get(key)));
        }
        // 模擬表單
        UrlEncodedFormEntity entity = new UrlEncodedFormEntity(paramList,"utf-8");
        httpPost.setEntity(entity);
      }
      // 執行http請求
      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) {
    // 建立Httpclient物件
    CloseableHttpClient httpClient = HttpClients.createDefault();
    CloseableHttpResponse response = null;
    String resultString = "";
    try {
      // 建立Http Post請求
      HttpPost httpPost = new HttpPost(url);
      // 建立請求內容
      StringEntity entity = new StringEntity(json,ContentType.APPLICATION_JSON);
      httpPost.setEntity(entity);
      // 執行http請求
      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.第三步就是簡單的測試程式碼了

public class WeChatAccessTokenTest {
  public static void main(String[] args) {
    Map<String,String> params = new HashMap<>();
    // TODO: 2018/11/16 *號改成真實appid
    params.put("appid","******");
    // TODO: 2018/11/16 *號改成真實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);
  }
}

以上就是微信公眾號基礎卻比較重要的獲取access_token操作了！

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希望本文所述對大家java程式設計有所幫助。