gin接收参数和返回数据

Posted 2022-01-26 issue是fw

tags:

篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了gin接收参数和返回数据相关的知识，希望对你有一定的参考价值。

返回JSON数据

方式一

用map作序列化

package main

import(
	"github.com/gin-gonic/gin"
)
func main()
	r := gin.Default()
	r.GET("/json",func(c *gin.Context)
		c.JSON(200,gin.H
			"name":"cl",
			"message":"kkk",
			"age":"19",
		)
	)
	r.Run()

其中gin.H是一种生成map[string]interface的快捷方式

方式二

返回struct作序列化

package main

import (
	"github.com/gin-gonic/gin"
	"net/http"
)
func main()
	r := gin.Default()

	type msg struct
		Name string
		Message string
		Age int
	
	r.GET("/struct_json",func(c *gin.Context)
		data := msg"cl","消息",19 
		c.JSON(http.StatusOK,data )
	)
	r.Run()

这里需要注意的是结构体的字段必须是以大写字母开头(对外暴露),否则接收不到

如果实在想返回首字母为小写,可以使用标签来解决

type msg struct
	Name string `json:"name"`
	Message string
	Age int

接收GET请求参数

package main

import (
	"github.com/gin-gonic/gin"
	"net/http"
)
func main()
	r := gin.Default()
	r.GET("/struct_json",func(c *gin.Context)
		name := c.Query("name")
		c.JSON(http.StatusOK,gin.H
			"你的名字是:":name,
		)
	)
	r.Run()

除了Query函数,还有下面两种方法取值

name := c.DefaultQuery("name","默认值")  //若不存在name参数,返回默认值(即第二个参数)

name,ok := c.GetQuery("name")  //ok表示是否存在name参数,不存在返回false

接收FORM表单参数

前端代码为

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <form action="/login" method="post" >
        <label for="username">username: </label>
        <input type="text" name="username" id="username">

        <label for="password">password: </label>
        <input type="password" name="password" id="password">

        <input type="submit">
    </form>
</body>
</html>

package main

import (
	"fmt"
	"github.com/gin-gonic/gin"
	"net/http"
)
func main()
	r := gin.Default()
	r.LoadHTMLFiles("./login.html")//解析网页

	r.GET("/login",func(c *gin.Context)//get请求就返回网页
		c.HTML( http.StatusOK,"login.html",nil )
	)
	r.POST("/login",func(c *gin.Context)//post请求就接收参数并打印出来
		username := c.PostForm("username")
		password := c.PostForm("password")
		fmt.Println("接收到参数username="+username+",password="+password )
	)
	r.Run()

类似上面的,除了PostForm方法外,还有GetPostForm和DefaultPostForm

获取url中的参数(restful风格)

如图所示,访问路径形如http://localhost:8080/user/username/password

其中username和password是参数名,实际值需要获取

package main

import (
	"github.com/gin-gonic/gin"
	"net/http"
)
func main()
	r := gin.Default()
	r.GET("/user/:username/:password",func(c *gin.Context)
		username := c.Param("username")
		password := c.Param("password")
		c.JSON( http.StatusOK,gin.H
			"username":username,
			"password":password,
		)
	)
	r.Run()

gin参数绑定

先定义结构体,然后直接用结构体的字段一次性匹配多个参数会更加方便

package main

import (
	"github.com/gin-gonic/gin"
	"net/http"
)
type User struct
	Username string ``
	Password string ``


func main()
	r := gin.Default()
	r.GET("/user",func(c *gin.Context)
		var me User
		err := c.ShouldBind( &me )
		if err != nil
			c.JSON(http.StatusBadRequest,gin.H
				"error":err.Error(),
			)
		else
			c.JSON(http.StatusOK,gin.H
				"user":me,
			)
		
	)
	r.Run()