简易ATM机

　　自动柜员机，语言O语言入即ATM，项目是实战指银行在不同地点设置一种小型机器，利用一张信用卡大小的老男胶卡上的磁带记录客户的基本户口资料(通常就是银行卡)，让客户可以通过机器进行提款、语言O语言入存款、项目转账等银行柜台服务，实战大多数客户都把这种自助机器称为自动提款机。老男本小节将模拟一个简易ATM机，语言O语言入实现其存款、项目取款、实战查询余额等功能。老男

　　需求分析

　　开发一个单机版简单的语言O语言入ATM机程序，暂不涉及数据库相关操作，b2b供应网项目实现只有一个用户的实战查询余额、取款、存款、退出功能。

　　在ATM程序运行之前，准备好一个账户名、账户对应的密码和账户对应的余额。程序运行提示输入密码，输入用户输入密码，并进行验证。如果输入正确则显示用户选择菜单(1.查询余额 2.存钱 3.取钱 4.退出)。

　　代码实现

　　代码示例：【23-1-1】

　　目录结构：

atm | —— controllers | | —— account.go | —— main.go

　　文件man.go是该ATM项目的入口文件，主要通过入口main函数实现用户密码验证、显示用户选择菜单和调用查询余额、云服务器提供商存钱、取钱、退出等功能，代码详情如下。

package main import ( "atm/controllers" "log" "net/http" ) func main() { http.HandleFunc("/query", controllers.Query) http.HandleFunc("/withdraw", controllers.Withdraw) http.HandleFunc("/deposit", controllers.Deposit) if err := http.ListenAndServe(":8080", nil); err != nil { log.Panic(err) } }

　　account.go文件实现用户操作相关的业务逻辑。文件中的Account结构体用于存储用户共有的属性，Withdraw方法用于用户的取款操作，Deposit方法用于用户的存款操作，Query方法用于用户的查询操作，代码详情如下。

package controllers import ( "encoding/json" "net/http" "strconv" ) type Account struct { UserName string Password string Amounts float64 } var account = Account{UserName: "oldboy", Password: "123456", Amounts: 10000} func Base(w http.ResponseWriter, r *http.Request) (user Account, code int, err string) { if r.Method != "POST" { err, code = "Method Not Allowed", http.StatusMethodNotAllowed return } userName, password := r.PostFormValue("user_name"), r.PostFormValue("password") money, _ := strconv.ParseFloat(r.PostFormValue("money"), 64) if userName == "" || password == "" { err, code = "fail parameter error", http.StatusBadRequest return } user = Account{UserName: userName, Password: password, Amounts: money} return } type ResponseJson struct { Code int `json:"code"` Data map[string]interface{} `json:"data"` Message string `json:"message"`} func SendOK(w http.ResponseWriter, res ResponseJson) { w.WriteHeader(http.StatusOK) bytes, _ := json.Marshal(res) w.Write(bytes) } // 取款 func Withdraw(w http.ResponseWriter, r *http.Request) { user, code, err := Base(w, r) if err != "" { http.Error(w, err, code) return } if user.Amounts <= 0 || user.Amounts > account.Amounts { http.Error(w, "fail parameter error", http.StatusBadRequest) return } if user.UserName == account.UserName && user.Password == account.Password { account.Amounts -= user.Amounts res := ResponseJson{Code: 200, Data: map[string]interface{}{ "user": account.UserName, "amounts": account.Amounts, }, Message: "取款成功！"} SendOK(w, res) } } // 存款 func Deposit(w http.ResponseWriter, r *http.Request) { user, code, err := Base(w, r) if err != "" { http.Error(w, err, code) return } if user.Amounts <= 0 { http.Error(w, "fail parameter error", http.StatusBadRequest) return } if user.UserName == account.UserName && user.Password == account.Password { account.Amounts += user.Amounts res := ResponseJson{Code: 200, Data: map[string]interface{}{ "user": account.UserName, "amounts": account.Amounts, }, Message: "存款成功！"} SendOK(w, res) } } // 查询 func Query(w http.ResponseWriter, r *http.Request) { user, code, err := Base(w, r) if err != "" { http.Error(w, err, code) return } if user.UserName == account.UserName && user.Password == account.Password { res := ResponseJson{Code: 200, Data: map[string]interface{}{ "user": account.UserName, "amounts": account.Amounts, }, Message: "查询成功！服务器托管"} SendOK(w, res) } }

　　查询：

curl -X POST -H "Content-Type:application/x-www-form-urlencoded" -d user\_name=oldboy&password=123456 "http://127.0.0.1:8080/query"

　　存钱：

curl -X POST -H "Content-Type:application/x-www-form-urlencoded" -d user\_name=oldboy&password=123456&money=1000 "http://127.0.0.1:8080/deposit"

　　取钱：

curl -X POST -H "Content-Type:application/x-www-form-urlencoded" -d user\_name=oldboy&password=123456&money=1000 "http://127.0.0.1:8080/withdraw"