android异常: java.net.ConnectException: localhost/127.0.0.1:8080

android手机做下载文件时，报了如下异常: 
java.net.ConnectException: localhost/127.0.0.1:8080 - Connection refused

模拟器默认把localhost或者127.0.0.1当做本身

在模拟器上可以用10.0.2.2代替127.0.0.1和localhost