Go Language Introduction (i) features, installation, environmental construction, the first program, etc.

The go language is a new programming language launched by Google that can reduce the complexity of your code without compromising application performance. Rob Pike, Google's Chief software engineer, said: "We've developed go because software development has been frustrating over the last more than 10 years."

Go language Features

1. Automatic garbage collection

• Memory is automatically recycled and no developers need to manage memory
• Just need new to allocate memory, no need to release

1. Has a richer built-in type

The go language supports a number of other advanced types, such as dictionary type map, array slicing (Slice), in addition to the simple built-in types supported by almost all languages, such as Integer and float.

1. Supports multiple return values for functions

In c,c++, including some other high-level languages, multiple function return values are not supported. But this feature is really needed, so in c it is generally done by defining the return value as a struct, or by returning it in the form of a function's argument reference. In the go language, as a new language, the target localization for the powerful language of course can not give up the satisfaction of this demand, so support function multiple return value is necessary.

1. Supports high concurrency

The go language introduces the Goroutine concept, which makes concurrent programming very simple. The go language makes concurrent programming lighter and more secure by using the concurrency mechanism of goroutine instead of the bare operating system, and by using message passing to share memory instead of using shared memory to communicate. By using the keyword go before a function call, we can let the function execute in goroutine mode, Goroutine is a more lightweight and resource-saving process than threading.

1. Error handling

In the traditional OOP programming, in order to catch the robustness of the program needs to catch the exception, most of the methods used are try () catch{} module, for example, in the following Java code, you may want to do:

 
 
1 try{
2     Statement stmt = ...;
3 }
4 catch(...){
5     ...
6 }
7 finally{
8     conn.close();
9 }

In go, three keywords are introduced, namely defer, panic, and recover, where the use of the DEFER keyword statement means that the code is executed automatically when the function exits, regardless of whether the program has an exception.
So above your Java code with Go process rewrite only two lines:

 
 
1 conn := ...
2 defer conn.Close()

Go Language Installation

The Go language supports the following systems:

• Linux
• Freebsd
• Mac OS X (also known as Darwin)
• Window

The installation package is: https://golang.org/dl/

After the Go language installation, the C:\Go directory has a total of 9 directories and 9 files, such as:

API -directory containing all API lists for easy access by the IDE

bin-directory, storing compiled executable files

Blog-Directory,

Doc-directory, help documentation

Lib-directory,

Misc-Catalogue,

pkg-directory, which holds the compiled package file. The files in the pkg are generated by Go compilation

src-directory, storing project source files

Note: In general, bin and pkg directories can not be created, the GO command will be created automatically (such as Go install), only need to create the SRC directory.

Common Commands

Go Build

The Go Build command compiles the source code files or packages we specify and their dependencies.

Go build-o bin/tongbupan Go_dev/tongbupan/main

-O: Specifies the directory and name after compilation

Go Install

The Go Install command is actually divided into two steps internally: The first step is to generate the result file (executable or. a), and the second step is to move the compiled results to the $GOPATH/pkg or $GOPATH/bin.

Go run

The Go Run command compiles and runs the command source file.

Note that it does not generate an. exe file and only produces a temporary file (but) that executes the results directly at the command-line output to facilitate user debugging.

Go get

Go get can download or update the specified code packages and their dependent packages from the Internet on demand and in real-time, and compile and install them.

Go test

The Go Test command automatically reads the file named *_test.go under the source directory and generates and runs the executable file for the test.

Go clean

The Go Clean command removes some files and directories that are generated when executing other commands

Go Doc & Godoc

The Go Doc command can print documents attached to the Go Language program entity. We can use the identifier of the program entity as the parameter of the command to achieve the purpose of viewing its document.

Godoc is a powerful tool that also shows the documentation for the specified code package.

Other commands

The Go language also provides other useful tools, such as:

Go fix is used to fix old version of code to new version, such as Go1 before the old version of the code into GO1

Go version View the current release of Go

Go env View the current GO environment variables

Go list lists all currently installed package

Go language development tools

Goland

Jetbrain's Goland is a powerful IDE, but only 30 days of free trial.

Liteide

Liteide is a simple open source IDE. It is noteworthy that it is the first IDE released by the Go Language 2012 release, developed by QT and looks like other compilers such as Visual Studio and GCC C + +.

Because it is designed directly for Golang, Liteide provides developers with many useful features, including configurable build commands, advanced code editors, and extensive golang support. Other features include code management, GDB and delve debugger, automatic completion and use of Wordapi themes, MIME type based systems, and more.

VS Code

It is a popular open source IDE developed by Microsoft and has an out-of-the-box go extension available for use with VS code code. The Vscode-go plugin provides developers with more features, including integration with many go tools.

VS Code provides smart completion functionality through IntelliSense, built-in Git integration, and direct debugging of code from the editor. VS code is highly scalable and offers many customization options through many of its extensions. It also provides support in dozens of languages, making it a popular tool for developers.

Eclipse Plugin Goclipse

Goclipse is a plugin for eclipse. Using the Goclipse plugin, developers can program with the popular Eclipse IDE. Both the Eclipse IDE and the Goclipse plugin are free and open source. The Goclipse Editor provides a wide range of features for developers, including source code editors, Project wizards, and builders to help report errors built in the editor, as well as full-featured GDB debugger support.

Development Environment Construction

Windows:

Download Go1.6.windows-amd64.msi installation file, install location select default C:\Go\

Configure environment variable Path:c:\go\bin after installation.

Then create a gopath environment variable, this variable is very important, I write the code to be placed in this variable in the configuration of the directory, the go compiler will find and compile;

Continue to create a goroot variable, with the Go compiler to install the target goroot:c:\go\;

After completing the above steps, open the command line Input # Go version, the Go compiler version number will appear.

Enter # Go env to see the right go environment.

Linux:

Linux deployment Golang, first of all, install the SSH Remote Tools on windows, such as XSHELL4.

1. Install mercurial package (mercurial version management system, can output HG name detection is installed)

sudo apt-get install mercurial or # sudo easy_install mercurial

2. Install git

sudo apt-get install git

3. Installing GCC

sudo apt-get install gcc

4. Download the Golang compression pack

wget https://storage.googleapis.com/golang/go1.6.linux-amd64.tar.gz

TAR-ZXVF Go1.6.linux-amd64.tar.gz-c/Home

Rename the unpacked folder to go

Add environment variable: # Vi/etc/profile

Add the following content to the profile

Export Goroot=/home/go

Export path= $GOROOT/bin: $PATH

Export gopath=/home/gopkg

Gopath and Goroot will be changed to your path.

Then we refresh the environment variable: #source/etc/profile

Finally, we verify that the installation was successful: # Go version

5. We can also install without downloading Golang's compression package

sudo apt-get install Golang

Go version

Mac:

Download go1.6.darwin-amd64.pkg installation file for installation

Or, after installing homebrew, enter the command:

Brew Update

Brew Install Mercurial

Brew Install Go

For installation.

Enter # Go version and the Go compiler will appear.

Enter # Go env to see the right go environment.

First Go program

Not mundane, the same as a Hello world.

 
1 package main
2 
3 import (
4     "fmt"
5 )
6 
7 func main() {
8     fmt.Println("Hello World")
9 }

Save the above code to "C:\mygo\src\hello.go", then open the command line, execute: Go install Hello, you can see the output: Hello World

Project Directory

Bin: Store the compiled executable file

PKG: Store the compiled package file

SRC: Storing project source files

Go Language Introduction (i) features, installation, environmental construction, the first program, etc.