Go语言设置JSON的默认值操作_Golang_

 package main import ( "encoding/json" "fmt" "net" "net/http" ) type JsonTest struct { Test1 string `json:"test1"` Test2 []string `json:"test2"` } //定义自己的路由器 type MyMux1 struct { } //实现http.Handler这个接口的唯一方法 func (mux *MyMux1) ServeHTTP(w http.ResponseWriter, r *http.Request) { urlPath := r.URL.Path switch urlPath { case "/test": mux.testJson(w, r) default: http.Error(w, "没有此url路径", http.StatusBadRequest) } } func (mux *MyMux1) testJson(w http.ResponseWriter, r *http.Request) { if r.Method != "GET" { http.Error(w, "the method is not allowed", http.StatusMethodNotAllowed) } jsontest := &JsonTest{} //只初始化Test1字段 jsontest.Test1 = "value1" jsondata,_ := json.Marshal(jsontest) w.Header().Set("Content-Type", "application/json") fmt.Fprintf(w, "%s", jsondata) } func main() { //实例化路由器Handler mymux := &MyMux1{} //基于TCP服务监听8088端口 ln, err := net.Listen("tcp", ":8089") 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") } } 

 func (mux *MyMux1) testJson(w http.ResponseWriter, r *http.Request) { if r.Method != "GET" { http.Error(w, "the method is not allowed", http.StatusMethodNotAllowed) } jsontest := &JsonTest{} jsontest.Test1 = "value1" jsontest.Test2 = make([]string, 0) jsondata,_ := json.Marshal(jsontest) w.Header().Set("Content-Type", "application/json") fmt.Fprintf(w, "%s", jsondata) } 

 package main import ( "fmt" "encoding/json" ) type Test struct { A string B int C string } func (t *Test) UnmarshalJSON(data []byte) error { type testAlias Test test := &testAlias{ A: "default A", B: -2, } _ = json.Unmarshal(data, test) *t = Test(*test) return nil } var example []byte = []byte(`[{"A": "1", "C": "3"}, {"A": "4", "B": 2}, {"C": "5"}]`) func main() { out := &[]Test{} _ = json.Unmarshal(example, &out) fmt.Print(out) }