这是我的代码，我想使用jsonrpc4j（1.0版）获取OVSDB消息
public static void main(String[] args) throws Throwable {
JsonRpcHttpClient jsonRpcHttpClient = new JsonRpcHttpClient(new URL("http://192.168.1.177:6632"));
String result = jsonRpcHttpClient.invoke("list_dbs", null, String.class);
System.out.println(result);
}
但是当我运行这段代码时，我得到了结果消息：
Exception in thread "main" java.net.SocketException: Unexpected end of file from server
at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:851)
at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:678)
at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:848)
at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:678)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1587)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1492)
at com.googlecode.jsonrpc4j.JsonRpcHttpClient.invoke(JsonRpcHttpClient.java:153)
at com.googlecode.jsonrpc4j.JsonRpcHttpClient.invoke(JsonRpcHttpClient.java:102)
at com.googlecode.jsonrpc4j.JsonRpcHttpClient.invoke(JsonRpcHttpClient.java:120)
at com.swjtu.Test.main(Test.java:21)
请帮助我解决这个问题，谢谢！