用CountDownLatch把java的websocket请求从异步修改为同步
目录
用CountDownLatch把java的websocket请求从异步修改为同步
在项目中，需要用websocket和其他服务器进行通信，而websocket是长连接，建立连接后，监听消息，然后进行消息的处理。也就是消息的异步处理。
使用java websocket需要实现的接口如下
public abstract void onOpen( ServerHandshake handshakedata );
public abstract void onMessage( String message );
public abstract void onClose( int code, String reason, boolean remote );
public abstract void onError( Exception ex );
public void onMessage( ByteBuffer bytes ) {
}
public void onFragment( Framedata frame ) {
}对于习惯使用同步请求的java开发者来说，用起来还是不方便的。
参考网上资料，CountDownLatch把java的websocket请求从异步修改为同步，如下：
package cc.openwiki.model;
import lombok.extern.slf4j.Slf4j;
import org.java_websocket.client.WebSocketClient;
import org.java_websocket.handshake.ServerHandshake;
import java.net.URI;
import java.nio.ByteBuffer;
import java.util.concurrent.CountDownLatch;
/**
* Created by admin on 2017/6/6.
*/
@Slf4j
public class WebSocketClientExt extends WebSocketClient {
public WebSocketClientExt(URI serverURI){
super(serverURI);
}
private Object lock = new Object();
private Object result = null;
private CountDownLatch downLatch = null;
public Object sendOb(Object object){
synchronized (lock){
downLatch = new CountDownLatch(1);
sendImpl(object);
try {
downLatch.await();
} catch (InterruptedException e) {
e.printStackTrace();
}finally {
return result;
}
}
}
public void sendImpl( Object object ){
if(object instanceof String){
super.send((String)object);
}else if(object instanceof byte[]){
super.send((byte[])object);
}
}
@Override
public void onOpen(ServerHandshake handshakedata) {
log.debug("open handshakedata。。。");
}
@Override
public void onMessage(String message) {
log.debug("receive message。。。");
result = message;
if(downLatch!=null){
downLatch.countDown();
}
}
public void onMessage( ByteBuffer bytes ) {
log.debug("receive ByteBuffer message。。。");
result = bytes;
if(downLatch!=null){
downLatch.countDown();
}
}
@Override
public void onClose(int code, String reason, boolean remote) {
log.debug("close websocket 。。");
}
@Override
public void onError(Exception ex) {
log.debug("onError 。。");
}
}调用方式如下：
WebSocketClientExt webSocketClientExt = new WebSocketClientExt(uri);
try {
webSocketClientExt.connectBlocking();
} catch (InterruptedException e) {
log.info("connect excepiont {}", e);
}
Object result = webSocketClientExt.sendOb(data.toByteArray());用起来是不是熟悉了 :)
by sim