Meaning of "_" Underline after Go import

Call its init function without calling its internal method
In the Golang, import is the role of importing other package, but today in the look at the Beego framework saw the import underline, do not know its meaning, so Baidu and solution.
Import underline (For example: import _ Hello/imp) Effect:
When importing a package, all init () functions are executed in the file under the package, however, sometimes we don't need to import the entire package, just want it to execute the init () function. You can use import to refer to the package at this time. Even if you refer to the package with the import _ package path only to invoke the Init () function, you cannot call other functions in the package by the package name.