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)
原文：http://blog.csdn.net/qq544529563/article/details/38784991