public static final String BASE_URL = "http://127.0.0.1:8090/HelloWord/"...;

会抛异常Caused by: libcore.io.ErrnoException: connect failed: ECONNREFUSED (Connection refused)

解决方法：

String url = "http://127.0.0.1:8090/HelloWord/"...;  修改成

public static final String BASE_URL = "http://192.168.3.14:8090/HelloWord"...;

主机ip不能使用localhost或者127.0.0.1，使用真实ip地址即可。

Android客户端连接tomcat时出错：connect failed: ECONNREFUSED (Connection refused)