백엔드 개발에 Go언어를 적용한 분석

package main

import (
    "fmt"
    "net/http"
)

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

    http.ListenAndServe(":8080", nil)
}

package main

import (
    "database/sql"
    "fmt"

    _ "github.com/go-sql-driver/mysql"
)

func main() {
    db, err := sql.Open("mysql", "root:password@tcp(127.0.0.1:3306)/test")
    if err != nil {
        fmt.Println("数据库连接失败：", err)
        return
    }
    defer db.Close()

    rows, err := db.Query("SELECT * FROM users")
    if err != nil {
        fmt.Println("查询失败：", err)
        return
    }
    defer rows.Close()

    for rows.Next() {
        var id int
        var name string
        err = rows.Scan(&id, &name)
        if err != nil {
            fmt.Println("读取数据失败：", err)
            return
        }
        fmt.Println("ID:", id, "Name:", name)
    }
}

package main

import (
    "fmt"
    "io"
    "net/http"
    "os"
)

func download(url string) {
    resp, err := http.Get(url)
    if err != nil {
        fmt.Println("下载失败：", err)
        return
    }
    defer resp.Body.Close()

    file, err := os.Create("downloaded_file.txt")
    if err != nil {
        fmt.Println("文件创建失败：", err)
        return
    }
    defer file.Close()

    _, err = io.Copy(file, resp.Body)
    if err != nil {
        fmt.Println("文件写入失败：", err)
        return
    }

    fmt.Println("下载完成：", url)
}

func main() {
    urls := []string{"http://example.com/image1.jpg", "http://example.com/image2.jpg", "http://example.com/image3.jpg"}
    for _, url := range urls {
        go download(url)
    }

    fmt.Scanln()
}