go post json数据

package main
import (
    "bytes"
    "encoding/json"
    "fmt"
    "io/ioutil"
    "net/http"
)
const url = "http://xxxxxxxxxxxxxxxxxx"
func postData() bool {
    data := make(map[string]string)
    data["username"] = "hequan"
    data["password"] = "password"
    b, _ := json.Marshal(data)
    resp, err := http.Post(url,
        "application/json",
        bytes.NewBuffer(b))
    if err != nil {
        fmt.Println(err)
    }
    defer resp.Body.Close()
    body, _ := ioutil.ReadAll(resp.Body)
    fmt.Println(string(body))
    return true
}
func main()  {
    postData()
}