阿里雲HttpClient跨天以後解析不了域名

也許這是一個少見的狀況，我使用HttpClient寫了一個調用第三方服務的請求，在本機測試和騰訊雲上測試都沒有問題，可是放到阿里雲以後，剛啓動的時候是沒有問題的，可是每次過零點以後，就會報異常：

java.net.UnknownHostException: www.xxxx.com: System error,異常棧以下：

java.net.UnknownHostException: wwww.xxx.com: System error
        at java.base/java.net.Inet4AddressImpl.lookupAllHostAddr(Native Method)
        at java.base/java.net.InetAddress$PlatformNameService.lookupAllHostAddr(InetAddress.java:925)
        at java.base/java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1505)
        at java.base/java.net.InetAddress$NameServiceAddresses.get(InetAddress.java:844)
        at java.base/java.net.InetAddress.getAllByName0(InetAddress.java:1495)
        at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1354)
        at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1288)
        at org.apache.http.impl.conn.SystemDefaultDnsResolver.resolve(SystemDefaultDnsResolver.java:45)
        at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:111)
        at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:353)
        at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:380)
        at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:236)
        at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:184)
        at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:88)
        at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
        at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:184)
        at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:82)
        at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:107)

只要重啓一下java進程就行了。

在網上查找，說是jvm dns緩存致使的，在啓動參數中添加下面兩個參數:

設置解析成功的域名記錄JVM中緩存的有效時間，這裏修改成1秒鐘有效，0表示禁止緩存，-1表示永遠有效

-Dsun.net.inetaddr.ttl=1 

設置解析失敗的域名記錄JVM中緩存的有效時間，這裏修改成1秒鐘有效，0表示禁止緩存，-1表示永遠有效

-Dsun.net.inetaddr.negative.ttl=1

可是我設置了，貌似沒有什麼效果，有條件的同窗能夠試試。

 

最終沒辦法 ，使用Java jdk 自帶的http服務從新寫了一個請求，觀察一段時間再也不報那個異常，具體緣由仍是清楚，若是有知道的，謝謝告知。

package global.util;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import javax.net.ssl.HttpsURLConnection;
import org.apache.http.Header;
import global.common.log.DKLog;

public class HttpUtil {
    //發送https post請求
    public static String sendHttpsPostRequest(String data, String requestUri, Header... headers) {
        DataOutputStream wr = null;
        BufferedReader in = null;
 　　　 HttpsUrlConnection con = null;
        try {
            URL obj = new URL(requestUri);
           //https請求
            con = (HttpsURLConnection) obj.openConnection();
            if(headers != null) {
                for(Header header : headers) {
                    con.setRequestProperty(header.getName(), header.getValue());
                }
            }
            con.setRequestProperty("Content-Type", " application/json");
            con.setConnectTimeout(15000);
            // 添加請求頭
            con.setRequestMethod("POST");
            // 發送Post請求
            con.setDoOutput(true);
            wr = new DataOutputStream(con.getOutputStream());
            wr.writeBytes(data);
            wr.flush();
            int responseCode = con.getResponseCode();
            if (responseCode == 200) {
                in = new BufferedReader(new InputStreamReader(con.getInputStream()));
                String inputLine;
                StringBuffer response = new StringBuffer();
                while ((inputLine = in.readLine()) != null) {
                    response.append(inputLine);
                }
                return response.toString();
            } else {
                DKLog.system.error("請求服務器異常，返回異常碼：{}", responseCode);
            }
        } catch (Exception e) {
            DKLog.system.error("Http請求失敗,{},data:{}", requestUri, data, e);
        } finally {
            if (wr != null) {
                try {
                    wr.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }

            }
            if(con != null){
　　　　　　　　　　con.disconnect();
             }
        }
        return null;
    }

}

 

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