optimise: create http client by connection pool (#14079)

dubbo-remoting/dubbo-remoting-http/src/main/java/org/apache/dubbo/remoting/http/config/HttpClientConfig.java

@@ -22,6 +22,10 @@ public class HttpClientConfig {
     private int connectTimeout = 6 * 1000;
     private int chunkLength = 8196;
 
+    private int maxIdleConnections = 20;
+
+    private int keepAliveDuration = 30 * 1000;
+
     private int HTTP_CLIENT_CONNECTION_MANAGER_MAX_PER_ROUTE = 20;
     private int HTTP_CLIENT_CONNECTION_MANAGER_MAX_TOTAL = 20;
     private int HTTPCLIENT_KEEP_ALIVE_DURATION = 30 * 1000;
@@ -57,4 +61,24 @@ public class HttpClientConfig {
     public int getChunkLength() {
         return chunkLength;
     }
+
+    public int getMaxIdleConnections() {
+
+        return maxIdleConnections;
+    }
+
+    public void setMaxIdleConnections(int maxIdleConnections) {
+
+        this.maxIdleConnections = maxIdleConnections;
+    }
+
+    public int getKeepAliveDuration() {
+
+        return keepAliveDuration;
+    }
+
+    public void setKeepAliveDuration(int keepAliveDuration) {
+
+        this.keepAliveDuration = keepAliveDuration;
+    }
 }

dubbo-remoting/dubbo-remoting-http/src/main/java/org/apache/dubbo/remoting/http/restclient/OKHttpRestClient.java

@@ -30,6 +30,7 @@ import java.util.concurrent.TimeUnit;
 
 import okhttp3.Call;
 import okhttp3.Callback;
+import okhttp3.ConnectionPool;
 import okhttp3.OkHttpClient;
 import okhttp3.Request;
 import okhttp3.RequestBody;
@@ -140,11 +141,15 @@ public class OKHttpRestClient implements RestClient {
     }
 
     public OkHttpClient createHttpClient(HttpClientConfig httpClientConfig) {
-        OkHttpClient client = new OkHttpClient.Builder()
+
+        return new OkHttpClient.Builder()
                 .readTimeout(httpClientConfig.getReadTimeout(), TimeUnit.SECONDS)
                 .writeTimeout(httpClientConfig.getWriteTimeout(), TimeUnit.SECONDS)
                 .connectTimeout(httpClientConfig.getConnectTimeout(), TimeUnit.SECONDS)
+                .connectionPool(new ConnectionPool(
+                        httpClientConfig.getMaxIdleConnections(),
+                        httpClientConfig.getKeepAliveDuration(),
+                        TimeUnit.SECONDS))
                 .build();
-        return client;
     }
 }