DefaultApacheHttpClientBuilder修改为单例模式

weixin-java-common/src/main/java/me/chanjar/weixin/common/util/http/apache/DefaultApacheHttpClientBuilder.java

@@ -68,13 +68,16 @@ public boolean retryRequest(IOException exception, int executionCount, HttpConte
    * 闲置连接监控线程
    */
   private IdleConnectionMonitorThread idleConnectionMonitorThread;
-  private HttpClientBuilder httpClientBuilder;
+  /**
+   * 持有client对象,仅初始化一次,避免多service实例的时候造成重复初始化的问题
+   */
+  private CloseableHttpClient closeableHttpClient;
 
   private DefaultApacheHttpClientBuilder() {
   }
 
   public static DefaultApacheHttpClientBuilder get() {
-    return new DefaultApacheHttpClientBuilder();
+    return DefaultApacheHttpClientBuilder.SingletonHolder.INSTANCE;
   }
 
   @Override
@@ -219,7 +222,7 @@ private synchronized void prepare() {
     this.idleConnectionMonitorThread.setDaemon(true);
     this.idleConnectionMonitorThread.start();
 
-    this.httpClientBuilder = HttpClients.custom()
+    HttpClientBuilder httpClientBuilder = HttpClients.custom()
       .setConnectionManager(connectionManager)
       .setConnectionManagerShared(true)
       .setSSLSocketFactory(this.buildSSLConnectionSocketFactory())
@@ -240,12 +243,13 @@ private synchronized void prepare() {
         new AuthScope(this.httpProxyHost, this.httpProxyPort),
         new UsernamePasswordCredentials(this.httpProxyUsername,
           this.httpProxyPassword));
-      this.httpClientBuilder.setDefaultCredentialsProvider(provider);
+      httpClientBuilder.setDefaultCredentialsProvider(provider);
     }
 
     if (StringUtils.isNotBlank(this.userAgent)) {
-      this.httpClientBuilder.setUserAgent(this.userAgent);
+      httpClientBuilder.setUserAgent(this.userAgent);
     }
+    this.closeableHttpClient = httpClientBuilder.build();
     prepared.set(true);
   }
 
@@ -277,7 +281,14 @@ public CloseableHttpClient build() {
     if (!prepared.get()) {
       prepare();
     }
-    return this.httpClientBuilder.build();
+    return this.closeableHttpClient;
+  }
+
+  /**
+   * DefaultApacheHttpClientBuilder 改为单例模式,并持有唯一的CloseableHttpClient(仅首次调用创建)
+   */
+  private static class SingletonHolder {
+    private static final DefaultApacheHttpClientBuilder INSTANCE = new DefaultApacheHttpClientBuilder();
   }
 
   public static class IdleConnectionMonitorThread extends Thread {

weixin-java-common/src/test/java/me/chanjar/weixin/common/util/http/apache/DefaultApacheHttpClientBuilderTest.java

@@ -0,0 +1,64 @@
+package me.chanjar.weixin.common.util.http.apache;
+
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+public class DefaultApacheHttpClientBuilderTest {
+  @Test
+  public void testBuild() throws Exception {
+    DefaultApacheHttpClientBuilder builder1 = DefaultApacheHttpClientBuilder.get();
+    DefaultApacheHttpClientBuilder builder2 = DefaultApacheHttpClientBuilder.get();
+    Assert.assertSame(builder1, builder2, "DefaultApacheHttpClientBuilder为单例,获取到的对象应该相同");
+    List<TestThread> threadList = new ArrayList<>(10);
+    for (int i = 0; i < 10; i++) {
+      TestThread thread = new TestThread();
+      thread.start();
+      threadList.add(thread);
+    }
+    for (TestThread testThread : threadList) {
+      testThread.join();
+      Assert.assertNotEquals(-1,testThread.getRespState(),"请求响应code不应为-1");
+    }
+
+    for (int i = 1; i < threadList.size(); i++) {
+      TestThread thread1 = threadList.get(i - 1);
+      TestThread thread2 = threadList.get(i);
+      Assert.assertSame(
+        thread1.getClient(),
+        thread2.getClient(),
+        "DefaultApacheHttpClientBuilder为单例,并持有了相同的HttpClient"
+      );
+    }
+  }
+
+
+  public static class TestThread extends Thread {
+    private CloseableHttpClient client;
+    private int respState = -1;
+
+    @Override
+    public void run() {
+      client = DefaultApacheHttpClientBuilder.get().build();
+      HttpGet httpGet = new HttpGet("http://www.sina.com.cn/");
+      try (CloseableHttpResponse resp = client.execute(httpGet)){
+        respState = resp.getStatusLine().getStatusCode();
+      } catch (IOException ignored) {
+      }
+    }
+
+    public CloseableHttpClient getClient() {
+      return client;
+    }
+
+    public int getRespState() {
+      return respState;
+    }
+  }
+}