Go语言学习14-常见任务
内置的 JSON 解析
利用反射实现, 通过 FieldTag 来标识对应的 json 值
type BasicInfo struct {Name string `json:"name"`Age int `json:"age"`
}
type JobInfo struct {Skills []string `json:"skills"`
}
type Employee struct {BasicInfo BasicInfo `json:"basic_info"`JobInfo JobInfo `json:"job_info"`
}
// embedded_json_test.go
var jsonStr = `{"basic_info":{"name":"Mike","age":30},"job_info":{"skills": ["Java", "Go", "C"]}
}`func TestEmbeddedJson(t *testing.T) {e := new(Employee)err := json.Unmarshal([]byte(jsonStr), e)if err != nil {t.Error(err)}fmt.Println(*e)if v, err := json.Marshal(e); err == nil {fmt.Println(string(v))} else {t.Error(err)}
}更快的 JSON 解析
EasyJSON 采用代码生成而非反射
安装
go get -u github.com/mailru/easyjson/...
使用
easyjson -all <结构定义>.go
HTTP Server
func main() {http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {fmt.Fprintf(w, "Hello World!")})http.HandleFunc("/time/", func(w http.ResponseWriter, r *http.Request) {t := time.Now()timeStr := fmt.Sprintf("{\"time\": \"%s\"}", t)w.Write([]byte(timeStr))})http.ListenAndServe(":8080", nil)
}
路由规则
-
URL 分为两种，末尾是 / ：表示一个子树，后面可以跟其他子路径； 末尾不 是 /，表示一个叶子，固定的路径
以/ 结尾的 URL 可以匹配它的任何子路径，比如 /images 会匹配 /images/cute-cat.jpg
-
它采用最长匹配原则，如果有多个匹配，一定采用匹配路径最长的那个进行处
理
-
如果没有找到任何匹配项，会返回 404 错误
Default Router
func (sh serverHandler) ServeHTTP(rw ResponseWriter, req *Request) {handler := sh.srv.Handlerif handler == nil {handler = DefaultServeMux}if req.RequestURI == "*" && req.Method == "OPTIONS" {handler = globalOptionsHandler{}}handler.ServeHTTP(rw, req)
}
构建Restful服务
更好的Router
https://github.com/julienschmidt/httprouter
func Hello(w http.ResponseWriter, r *http.Request, ps httprouter.Params) { fmt.Fprintf(w, "hello, %s!\n", ps.ByName("name"))
}func main() {router := httprouter.New() router.GET("/", Index)router.GET("/hello/:name", Hello)log.Fatal(http.ListenAndServe(":8080", router))
}面向资源的架构(Resource Oriented Architecture)
In software engineering, a resource-oriented architecture (ROA) is a style of software architecture and programming paradigm for supportive designing and developing software in the form of Internetworking of resources with “RESTful” interfaces.
type Employee struct {ID string `json:"id"`Name string `json:"name"`Age int `json:"age"`
}var employeeDB map[string]*Employeefunc init() {employeeDB = map[string]*Employee{}employeeDB["Mike"] = &Employee{ID: "e-1",Name: "Mike",Age: 35,}employeeDB["Rose"] = &Employee{ID: "e-2",Name: "Rose",Age: 45,}
}func Index(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {fmt.Fprint(w, "Welcome!\n")
}func GetEmployeeByName(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {qName := ps.ByName("name")var (ok boolinfo *EmployeeinfoJson []byteerr error)if info, ok = employeeDB[qName]; !ok {w.Write([]byte("{\"error\":\"Not Found\"}"))return}if infoJson, err = json.Marshal(info); err != nil {w.Write([]byte(fmt.Sprintf("{\"error\":,\"%s\"}", err)))return}w.Write(infoJson)
}func main() {router := httprouter.New()router.GET("/", Index)router.GET("/employees/:name", GetEmployeeByName)log.Fatal(http.ListenAndServe("localhost:8080", router))
}
