gin框架学习

Gin框架

web开发本质

go mod init 项目名

package main

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

func sayHello(w http.ResponseWriter,r *http.Request){
	b,_:=ioutil.ReadFile("./hello.txt")
	_,_=fmt.Fprintln(w,string(b))
}

func main() {
	http.HandleFunc("/hello",sayHello)
	err:=http.ListenAndServe(":8080",nil)
	if err!=nil{
		fmt.Println("http serve failed...")
		return
	}
	
}

gin框架初识

下载

go get -u github.com/gin-gonic/gin

package main

import(
	"github.com/gin-gonic/gin"
)

func sayHello(c *gin.Context){
	c.JSON(200,gin.H{
		"message":"hello golang",
	})
}

func main() {
	r:=gin.Default()
	r.GET("hello",sayHello)
	//启动服务
	r.Run()
}

gin框架返回json

package main

import (
	"github.com/gin-gonic/gin"
	"net/http"
)

func main() {
	r := gin.Default()

	// gin.H 是map[string]interface{}的缩写
	r.GET("/someJSON", func(c *gin.Context) {
		// 方式一：自己拼接JSON
		c.JSON(http.StatusOK, gin.H{"message": "Hello world!"})
	})
	r.GET("/moreJSON", func(c *gin.Context) {
		// 方法二：使用结构体
		var msg struct {
			Name    string `json:"user"`
			Message string
			Age     int
		}
		msg.Name = "小王子"
		msg.Message = "Hello world!"
		msg.Age = 18
		c.JSON(http.StatusOK, msg)
	})
	r.Run(":8080")
}

gin返回query参数

package main

import (
	"github.com/gin-gonic/gin"
	"net/http"
)

func main() {
	r := gin.Default()
	r.GET("/web", func(ctx *gin.Context) {
		name := ctx.Query("query")
		age := ctx.Query("age")
		ctx.JSON(http.StatusOK, gin.H{
			"name": name,
			"age":  age,
		})
	})
	r.Run()
}

获取form表单参数

package main

import (
	"github.com/gin-gonic/gin"
	"net/http"
)

func main() {
	r := gin.Default()
	r.LoadHTMLFiles("./login.html")
	r.GET("/login",func(ctx *gin.Context) {
		ctx.HTML(http.StatusOK,"login.html",nil)
	})

	
	r.POST("/login", func(c *gin.Context) {
		// DefaultPostForm取不到值时会返回指定的默认值
		//username := c.DefaultPostForm("username", "小王子")
		username := c.PostForm("username")
		address := c.PostForm("address")
		//输出json结果给调用方
		c.JSON(http.StatusOK, gin.H{
			"message":  "ok",
			"username": username,
			"address":  address,
		})
	})
	
	
	
	err := r.Run()
	if err != nil {
		return
	}
}

获取url路径参数

package main

import (
	"github.com/gin-gonic/gin"
	"net/http"
)

func main() {
	r := gin.Default()
	r.GET("/user/:username/:age", func(c *gin.Context) {
		username := c.Param("username")
		age := c.Param("age")
		//输出json结果给调用方
		c.JSON(http.StatusOK, gin.H{
			"message":  "ok",
			"username": username,
			"address":  age,
		})
	})

	err := r.Run()
	if err != nil {
		return
	}
}

gin框架使用参数绑定(json)

package main

import (
	"fmt"
	"net/http"

	"github.com/gin-gonic/gin"
)

func main() {
	r := gin.Default()
	type Login struct {
		User     string `form:"user" json:"user" binding:"required"`
		Password string `form:"password" json:"password" binding:"required"`
	}

	r.POST("/json", func(c *gin.Context) {
		var login Login

		if err := c.ShouldBind(&login); err == nil {
			fmt.Printf("login info:%#v\n", login)
			c.JSON(http.StatusOK, gin.H{
				"user":     login.User,
				"password": login.Password,
			})
		} else {
			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		}
	})

	err := r.Run()
	if err != nil {
		return
	}
}

gin框架重定向

package main

import (
	"net/http"

	"github.com/gin-gonic/gin"
)

func main() {
	r := gin.Default()
	//http重定向
	r.GET("/test", func(c *gin.Context) {
		c.Redirect(http.StatusMovedPermanently, "https://www.baidu.com/")
	})
	r.GET("/test2", func(c *gin.Context) {
		// 指定重定向的URL
		c.Request.URL.Path = "/test3"
		r.HandleContext(c)
	})
	r.GET("/test3", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{"hello": "world"})
	})

	err := r.Run()
	if err != nil {
		return
	}
}

gin框架路由组

func main() {
	r := gin.Default()
	userGroup := r.Group("/user")
	{
		userGroup.GET("/index", func(c *gin.Context) {...})
		userGroup.GET("/login", func(c *gin.Context) {...})
		userGroup.POST("/login", func(c *gin.Context) {...})

	}
	shopGroup := r.Group("/shop")
	{
		shopGroup.GET("/index", func(c *gin.Context) {...})
		shopGroup.GET("/cart", func(c *gin.Context) {...})
		shopGroup.POST("/checkout", func(c *gin.Context) {...})
	}
	r.Run()
}