package mainimport ("fmt""os"
)func main(){fmt.Printf("命令行参数有%d个\n",len(os.Args))for i,v := range os.Args {fmt.Printf("当前是第%d个参数,参数是%s\n",i+1,v)}
}

package mainimport ("flag""fmt"
)func main()  {var username stringvar password stringvar host stringvar port intflag.StringVar(&username,"u","","database username ,default empty")flag.StringVar(&password,"p","","database password,default empty")flag.StringVar(&host,"h","","database host,default empty")flag.IntVar(&port,"port",3306,"database host port,default 3306")flag.Parse()fmt.Printf("username=%s\n",username)fmt.Printf("password=%s\n",password)fmt.Printf("host=%s\n",host)fmt.Printf("username=%s\n",username)fmt.Printf("port=%d\n",port)// ./main.exe -u root -p 1201 -h 127.0.0.1 -port 33306//username=root//password=1201//host=127.0.0.1//username=root//port=33306
}

package mainimport ("encoding/json""fmt"
)// 如果需要序列化后的key 名自定义,需要使用tag
type Person struct {Name string `json:"username"`Age  int    `json:"person_age"`// 对于结构体内不能导出字段// 首字母小写的// 无法序列化extra string
}
func marshal(data interface{}) {body, err := json.Marshal(data)if err != nil {fmt.Println(err)fmt.Println("序列化失败")return}fmt.Print("序列化后的数据为:")fmt.Println(string(body))}
func structToJSON() {person := Person{"Tom",21,"i want be a teacher"}marshal(person)// {"username":"Tom","person_age":21}
}
func mapToJSON() {person := make(map[string]interface{})person["name"] = "Jack"person["age"] = 20person["extra"] = "i want play game"marshal(person) // {"age":20,"extra":"i want play game","name":"Jack"}
}
func sliceToJSON(){person := make([]string,0)person = append(person,"Tom")person = append(person,"Jack")person = append(person,"hey")marshal(person) // ["Tom","Jack","hey"]
}
func main() {structToJSON()mapToJSON()sliceToJSON()
}

package mainimport ("encoding/json""fmt"
)func unmarshalMap(){str := `{"name":"tom","age":21,"extra":"i am english teacher"}`var person map[string]interface{}err := json.Unmarshal([]byte(str),&person)if err != nil {fmt.Println("JSON 反序列化失败")fmt.Println(err)return}fmt.Print("序列化的结果为:")fmt.Println(person) //map[age:21 extra:i am english teacher name:tom]
}
func unmarshalSlice(){str := `["tom","jack","hey","joy"]`var person []stringerr := json.Unmarshal([]byte(str),&person)if err != nil {fmt.Println("JSON 反序列化失败")fmt.Println(err)return}fmt.Print("序列化的结果为:")fmt.Println(person) //[tom jack hey joy]
}func unmarshalStruct(){str := `{"name":"tom","age":21,"extra":"i am english teacher"}`var person struct{Name stringAge int// 反序列化也一样,如果是不可导出字段// 则不能反序列化extra string}err := json.Unmarshal([]byte(str),&person)if err != nil {fmt.Println("JSON 反序列化失败")fmt.Println(err)return}fmt.Print("序列化的结果为:")fmt.Println(person) //{tom 21 }
}
func main(){unmarshalMap()unmarshalStruct()unmarshalSlice()
}