com.yuweix.kuafu.http.strategy.connect.KeepAliveStrategy Maven / Gradle / Ivy
package com.yuweix.kuafu.http.strategy.connect;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import org.apache.http.HeaderElement;
import org.apache.http.HeaderElementIterator;
import org.apache.http.HttpResponse;
import org.apache.http.impl.client.DefaultConnectionKeepAliveStrategy;
import org.apache.http.message.BasicHeaderElementIterator;
import org.apache.http.protocol.HTTP;
import org.apache.http.protocol.HttpContext;
/**
* 设置长连接策略，根据服务器的约束或者客户端的约束来设置长连接的时长；
* @author yuwei
*/
public class KeepAliveStrategy extends DefaultConnectionKeepAliveStrategy {
private static volatile KeepAliveStrategy instance = null;
private static final Lock lock = new ReentrantLock();
private KeepAliveStrategy() {
}
public static KeepAliveStrategy get() {
if (instance == null) {
lock.lock();
try {
if (instance == null) {
instance = new KeepAliveStrategy();
}
} finally {
lock.unlock();
}
}
return instance;
}
/**
* 返回超时时间(ms)；
*
* 服务器端配置（以tomcat为例）：keepAliveTimeout=60000，表示在60s内内，服务器会一直保持连接状态。
* 也就是说，如果客户端一直请求服务器，且间隔未超过60s，则该连接将一直保持，如果60s内未请求，则超时。
*/
@Override
public long getKeepAliveDuration(HttpResponse response, HttpContext context) {
/**
* 如果服务器指定了超时时间，则以服务器的超时时间为准
*/
HeaderElementIterator itr = new BasicHeaderElementIterator(response.headerIterator(HTTP.CONN_KEEP_ALIVE));
while (itr.hasNext()) {
HeaderElement ele = itr.nextElement();
String param = ele.getName();
String value = ele.getValue();
if (value != null && "timeout".equalsIgnoreCase(param)) {
try {
return Long.parseLong(value) * 1000;
} catch (NumberFormatException e) {
throw new RuntimeException("Invalid value of parameter timeout, that is [" + value + "].", e);
}
}
}
long keepAlive = super.getKeepAliveDuration(response, context);
/**
* 如果服务器未指定超时时间，则客户端默认30s超时
*/
if (keepAlive == -1) {
keepAlive = 30L * 1000;
}
return keepAlive;
}
}