gin路由篇

1. 基本路由

gin 框架中采用的路由库是基于httprouter做的

import ("net/http""github.com/gin-gonic/gin"
)func main() {// 1.创建路由r := gin.Default()// 2.绑定路由规则，执行的函数// gin.Context，封装了request和responser.GET("/", func(c *gin.Context) {c.String(http.StatusOK, "hello World!")})// 3.监听端口，默认在8080// Run("里面不指定端口号默认为8080") r.Run(":8000")
}

2. Restful风格的API

gin支持Restful风格的API

获取文章 /blog/getXxx Get blog/Xxx
添加 /blog/addXxx POST blog/Xxx
修改 /blog/updateXxx PUT blog/Xxx
删除 /blog/delXxxx DELETE blog/Xxx

3. API参数

可以通过Context的Param方法来获取API参数

package mainimport ("net/http""strings""github.com/gin-gonic/gin"
)func main() {r := gin.Default()r.GET("/user/:name/*action", func(c *gin.Context) {name := c.Param("name")action := c.Param("action")//截取/action = strings.Trim(action, "/")c.String(http.StatusOK, name+" is "+action)})//默认为监听8080端口r.Run(":8000")
}

4. URL参数

URL参数可以通过DefaultQuery()或Query()方法获取
DefaultQuery()若参数不村则，返回默认值，Query()若不存在，返回空串
API?name=zs

package mainimport ("fmt""net/http""github.com/gin-gonic/gin"
)func main() {r := gin.Default()r.GET("/user", func(c *gin.Context) {//指定默认值//http://localhost:8080/user 才会打印出来默认的值name := c.DefaultQuery("name", "枯藤")c.String(http.StatusOK, fmt.Sprintf("hello %s", name))})r.Run()
}

5. 表单参数

表单传输为post请求，http常见的传输格式为四种：
- application/json
- application/x-www-form-urlencoded
- application/xml
- multipart/form-data
表单参数可以通过PostForm()方法获取，该方法默认解析的是x-www-form-urlencoded或from-data格式的参数

    <form action="http://localhost:8080/form" method="post" action="application/x-www-form-urlencoded">用户名：<input type="text" name="username" placeholder="请输入你的用户名">  <br>密&nbsp;&nbsp;&nbsp;码：<input type="password" name="userpassword" placeholder="请输入你的密码">  <br><input type="submit" value="提交"></form>

package main//
import ("fmt""net/http""github.com/gin-gonic/gin"
)func main() {r := gin.Default()r.POST("/form", func(c *gin.Context) {types := c.DefaultPostForm("type", "post")username := c.PostForm("username")password := c.PostForm("userpassword")// c.String(http.StatusOK, fmt.Sprintf("username:%s,password:%s,type:%s", username, password, types))c.String(http.StatusOK, fmt.Sprintf("username:%s,password:%s,type:%s", username, password, types))})r.Run()
}

6. 上传单个文件

multipart/form-data格式用于文件上传
gin文件上传与原生的net/http方法类似，不同在于gin把原生的request封装到c.Request中

<form action="http://localhost:8080/upload" method="post" enctype="multipart/form-data">上传文件:<input type="file" name="file" ><input type="submit" value="提交"></form>

package mainimport ("github.com/gin-gonic/gin"
)func main() {r := gin.Default()//限制上传最大尺寸r.MaxMultipartMemory = 8 << 20r.POST("/upload", func(c *gin.Context) {file, err := c.FormFile("file")if err != nil {c.String(500, "上传图片出错")}// c.JSON(200, gin.H{"message": file.Header.Context})c.SaveUploadedFile(file, file.Filename)c.String(http.StatusOK, file.Filename)})r.Run()
}

7. 上传多个文件

<form action="http://localhost:8000/upload" method="post" enctype="multipart/form-data">上传文件:<input type="file" name="files" multiple><input type="submit" value="提交"></form>

package mainimport ("github.com/gin-gonic/gin""net/http""fmt"
)// gin的helloWorldfunc main() {// 1.创建路由// 默认使用了2个中间件Logger(), Recovery()r := gin.Default()// 限制表单上传大小 8MB，默认为32MBr.MaxMultipartMemory = 8 << 20r.POST("/upload", func(c *gin.Context) {form, err := c.MultipartForm()if err != nil {c.String(http.StatusBadRequest, fmt.Sprintf("get err %s", err.Error()))}// 获取所有图片files := form.File["files"]// 遍历所有图片for _, file := range files {// 逐个存if err := c.SaveUploadedFile(file, file.Filename); err != nil {c.String(http.StatusBadRequest, fmt.Sprintf("upload err %s", err.Error()))return}}c.String(200, fmt.Sprintf("upload ok %d files", len(files)))})//默认端口号是8080r.Run(":8000")
}

8. routes group

routes group是为了管理一些相同的URL

package mainimport ("github.com/gin-gonic/gin""fmt"
)// gin的helloWorldfunc main() {// 1.创建路由// 默认使用了2个中间件Logger(), Recovery()r := gin.Default()// 路由组1 ，处理GET请求v1 := r.Group("/v1")// {} 是书写规范{v1.GET("/login", login)v1.GET("submit", submit)}v2 := r.Group("/v2"){v2.POST("/login", login)v2.POST("/submit", submit)}r.Run(":8000")
}func login(c *gin.Context) {name := c.DefaultQuery("name", "jack")c.String(200, fmt.Sprintf("hello %s\n", name))
}func submit(c *gin.Context) {name := c.DefaultQuery("name", "lily")c.String(200, fmt.Sprintf("hello %s\n", name))
}