### get，列出列表
GET http://localhost:5000/users?pageIndex=1&pageSize=5&searchKey=17


### get，列出指定的用户
GET http://localhost:5000/users/2


### post请求，一般用于新增
POST http://localhost:5000/users HTTP/1.1
Content-Type: application/json

{
    "username":"再一个",
    "password":"123"
}


### put请求，一般用于修改
PUT http://localhost:5000/users/2 HTTP/1.1
Content-Type: application/json

{
    "username":"行吗",
    "password":"吗"
}


### 删除指定用户
DELETE http://localhost:5000/users/1 HTTP/1.1