Android simulator access to localhost or 127.0.0.1 error

In the general development of Java Web programs, We usually use localhost or 127.0.0.1来 to access the native Web service, but if we use the same address in the Android emulator to access it, the Android emulator will not be able to access our services properly, why is it? We can understand this: Android is the Linux kernel, including Android itself is an operating system, therefore, At this point we entered the browser in the simulator localhost or 127.0.0.1 represents the Android simulator (Android virtual machine), not your computer, understand? This is why you will report "Web page not available" When you use localhost in the emulator.

So how do you get access to Web apps on your local computer? On Android, map the address of our local computer to 10.0.2.2, so you can access the Web resources on the local computer on the emulator by simply replacing the original localhost or 127.0.0.1 with 10.0.2.2.
Then we'll start Tomcat on the computer, then run the Android emulator, open the browser on the emulator, and then visit: did http://10.0.2.2:8888 already see that cute tomcat cat? Access is as shown. (Note: On my computer, the Tomcat service uses a port of 8888, which by default is 8080)

Android simulator access to localhost or 127.0.0.1 error