我正在尝试使用socket.io连接到Geoloqi
托管的流媒体服务器我直接从github抓取了Gottox socket.io-java-client代码并且没有做任何修改,除了更改网址,但它给了我“握手时出错”的消息。网址应该是我从Geoloqi的制作者那里得到的:https://community.geoloqi.com/discussion/19/data-streaming#Item_11(参见第1回复)。
以下是来自BasicExample.java的代码
package basic;
/*
* socket.io-java-client Test.java
*
* Copyright (c) 2012, Enno Boland
* socket.io-java-client is a implementation of the socket.io protocol in Java.
*
* See LICENSE file for more information
*/
import io.socket.IOAcknowledge;
import io.socket.IOCallback;
import io.socket.SocketIO;
import io.socket.SocketIOException;
import org.json.JSONException;
import org.json.JSONObject;
public class BasicExample implements IOCallback {
private SocketIO socket;
/**
* @param args
*/
public static void main(String[] args) {
try {
new BasicExample();
} catch (Exception e) {
e.printStackTrace();
}
}
public BasicExample() throws Exception {
socket = new SocketIO();
// socket.connect("http://localhost:8080/", this);
socket.connect("https://subscribe.geoloqi.com:443", this);
// Sends a string to the server.
socket.send("Hello Server");
// Sends a JSON object to the server.
socket.send(new JSONObject().put("key", "value").put("key2",
"another value"));
// Emits an event to the server.
socket.emit("event", "argument1", "argument2", 13.37);
}
@Override
public void onMessage(JSONObject json, IOAcknowledge ack) {
try {
System.out.println("Server said:" + json.toString(2));
} catch (JSONException e) {
e.printStackTrace();
}
}
@Override
public void onMessage(String data, IOAcknowledge ack) {
System.out.println("Server said: " + data);
}
@Override
public void onError(SocketIOException socketIOException) {
System.out.println("an Error occured");
socketIOException.printStackTrace();
}
@Override
public void onDisconnect() {
System.out.println("Connection terminated.");
}
@Override
public void onConnect() {
System.out.println("Connection established");
}
@Override
public void on(String event, IOAcknowledge ack, Object... args) {
System.out.println("Server triggered event '" + event + "'");
}
}
以下是错误消息:
an Error occured
io.socket.SocketIOException: Error while handshaking
at io.socket.IOConnection.handshake(IOConnection.java:322)
at io.socket.IOConnection.access$7(IOConnection.java:292)
at io.socket.IOConnection$ConnectThread.run(IOConnection.java:199)
Caused by: java.lang.NullPointerException
at io.socket.IOConnection.handshake(IOConnection.java:302)
... 2 more
May 1, 2013 10:02:49 PM io.socket.IOConnection cleanup
INFO: Cleanup
代码出了什么问题?
答案 0 :(得分:9)
查看异常来自的source code(IOConnection.java:302
,来自内部NullPointerException
),这是代码块:
if (connection instanceof HttpsURLConnection) {
((HttpsURLConnection) connection)
.setSSLSocketFactory(sslContext.getSocketFactory());
}
显然connection
必须为非null,否则它将无法通过instanceof
测试。因此,sslContext
必须为null。由于sslContext
和setSslContext()
引用getSslContext()
的文件中唯一的其他位置,唯一合乎逻辑的结论是在制作之前必须调用setSslContext()
SSL连接。 SocketIO.setDefaultSSLSocketFactory()
也会调用IOConnection.setSslContext()
,因此您也可以调用它。
试试这个:
SocketIO.setDefaultSSLSocketFactory(SSLContext.getDefault());
socket = new SocketIO();
socket.connect("https://subscribe.geoloqi.com:443", this);
...
答案 1 :(得分:0)
当我使用https://github.com/Gottox/socket.io-java-client创建Java客户端时,我遇到了同样的错误。好像我的服务器基于1.X,这只支持1.0(https://github.com/Gottox/socket.io-java-client/issues/101)。通过使用https://github.com/socketio/socket.io-client-java来解决。