What are the essential Go language packages?

Title: Essential Go language packages and specific code examples

As an efficient and concise programming language, Go language has a rich standard library, some of which Packages are essential in the development process. This article will introduce some essential Go language packages and provide specific code examples to illustrate their usage and function.

1. fmt package

The fmt package provides functions for formatting input and output and is one of the most commonly used packages in the Go language. It can be used to format output variables, print debugging information, etc.

package main

import "fmt"

func main() {
    fmt.Println("Hello, World!")
}

2. os package

The os package provides functions for interacting with the operating system, which can be used to read and write files, obtain environment variables, etc.

package main

import (
    "fmt"
    "os"
)

func main() {
    file, err := os.Open("test.txt")
    if err != nil {
        fmt.Println("Error:", err)
        return
    }
    defer file.Close()
}

3. net/http package

The net/http package provides HTTP client and server functions and can be used to build a Web server, send HTTP requests, etc.

package main

import (
    "fmt"
    "net/http"
)

func handler(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintf(w, "Hello, World!")
}

func main() {
    http.HandleFunc("/", handler)
    http.ListenAndServe(":8080", nil)
}

4. encoding/json package

encoding/json package provides JSON data encoding and decoding functions, which can convert Go data structure into JSON format, or JSON data Decoded into Go data structure.

package main

import (
    "encoding/json"
    "fmt"
)

type Person struct {
    Name string `json:"name"`
    Age int `json:"age"`
}

func main() {
    p := Person{Name: "Alice", Age: 30}
    data, _ := json.Marshal(p)
    fmt.Println(string(data))

    var p2 Person
    json.Unmarshal(data, &p2)
    fmt.Println(p2)
}

The above are some essential packages and their specific code examples in Go language development. They can help us complete project development more efficiently. Of course, in addition to these packages, the Go language standard library has more powerful functions waiting for us to explore and apply. I hope this article will be helpful to readers, let's explore more possibilities in the world of Go language together!

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