Go语言实现的简单Web Services（接上一篇代码讲解示例）

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Go语言实现WebService(添加Json格式化例子)

1. 代码如下

package main
import ("bufio""encoding/json""fmt""log""net""net/http""strconv"
)
//定义自己的路由器
type MyMux struct{}
type point struct {Metric string			`json:"metric"`TimeStamp int64			`json:"timestamp"`Value float64			`json:"value"`Tags map[string]string	`json:"tags"`
}type responseExample struct {Message string	`json:"message"`Error 	string	`json:"error"`
}func (mux *MyMux) sayHello(w http.ResponseWriter, r *http.Request) {if r.Method != "GET" {http.Error(w, "the method is not allowed！", http.StatusMethodNotAllowed)return}_, err:=  fmt.Fprintf(w, "Hello World!")fmt.Printf("在控制台输出Hello,World!\n")if err != nil{http.Error(w, "控制台打印出错1", http.StatusExpectationFailed)return}
}func (mux *MyMux) sayHi(w http.ResponseWriter, r *http.Request){if r.Method != "POST"{http.Error(w, "the method is not allowed！", http.StatusMethodNotAllowed)return}_, err:=  fmt.Fprintf(w, "Hi World!")fmt.Printf("在控制台输出Hi,World!\n")if err != nil{http.Error(w, "控制台打印出错2", http.StatusExpectationFailed)return}
}func (mux *MyMux) writeJsonToClient(w http.ResponseWriter, r *http.Request){response := make([]*responseExample,3)//初始化response的信息for index, _ := range response{response[index] = &responseExample{Message: "this is test message "+strconv.Itoa(index),Error:"this is test error "+strconv.Itoa(index),}}//解析go结构体变量为json数据jsonData, err:= json.Marshal(response)if err != nil{log.Fatalf("JSON marshaling  failed: %s",err)}w.Header().Set("Content-Type","application/json")//打印到控制台fmt.Printf("%s\n", jsonData)//打印到浏览器_, _ = fmt.Fprintf(w, "%s\n", jsonData)
}func (muc *MyMux) parseJsonFromClient(w http.ResponseWriter, r *http.Request){if r.Method != "POST"{http.Error(w, "the method is not allowed", http.StatusMethodNotAllowed)}if r.Header.Get("Content-TyPe") != "application/json"{http.Error(w, "please set Encode method application/json", http.StatusBadRequest)}//流式解码器br := bufio.NewReader(r.Body)// 查看前1个字节f, err := br.Peek(1)if err != nil || len(f) != 1 {http.Error(w, "peek error: "+err.Error(), http.StatusBadRequest)return}// Peek to see if this is a JSON array.var multi boolswitch f[0] {case '{':multi = falsecase '[':multi = truedefault:http.Error(w, "expected JSON array or hash", http.StatusBadRequest)return}dps := make([]point,1)//如果是多个对象{}组成的数组[],那么久解码到dpsif dec := json.NewDecoder(br);multi{if err := dec.Decode(&dps); err!=nil{http.Error(w, "json array decode error", http.StatusBadRequest)return}}else{//否则，解码到dps[0]if err = dec.Decode(&dps[0]); err != nil {http.Error(w, "json object decode error", http.StatusBadRequest)return}}// fmt.Print(len(dps))// fmt.Print(dps)jsonData, err:= json.Marshal(dps)if err!= nil{log.Fatalf("JSON marshaling  failed: %s",err)}w.Header().Set("Content-Type","application/json")fmt.Printf("%s\n", jsonData)_, _ = fmt.Fprintf(w, "%s\n", jsonData)//_, _ = fmt.Fprint(w, jsonData)
}
//实现http.Handler这个接口的唯一方法
func (mux *MyMux) ServeHTTP(w http.ResponseWriter, r *http.Request){urlPath := r.URL.Pathswitch urlPath{case "/hello":mux.sayHello(w, r)case "/hi":mux.sayHi(w, r)case "/jsonPost":mux.parseJsonFromClient(w, r)case "/jsonGet":mux.writeJsonToClient(w, r)default:http.Error(w, "没有此url路径", http.StatusBadRequest)}
}func main(){//实例化路由器Handlermymux := &MyMux{}//基于TCP服务监听8088端口ln, err := net.Listen("tcp", ":8088")if err != nil{fmt.Printf("设置监听端口出错...")}//调用http.Serve(l net.Listener, handler Handler)方法，启动监听err1 := http.Serve(ln, mymux)if err1 != nil{fmt.Printf("启动监听出错")}
}