Go-json解码到结构体-踩坑详解编程语言

package main 
 
import ( 
	"encoding/json" 
	"fmt" 
) 
 
type User struct { 
	Name string `json:"name"` 
} 
 
func main() { 
	var u User 
	fmt.Printf("u=%+v, &u=%p/n", u, &u) //output: u={Name:}, &u=0xc00003e230 
	json.Unmarshal([]byte(`{"name":"polaris"}`), &u) 
	fmt.Printf("u.Name=%+v/n", u.Name) //output: u.Name=polaris 
 
	//var u1 *User 
	//fmt.Printf("u1=%+v, &u1=%p/n", u1, &u1) //output: u1=<nil>, &u1=0xc00007a028 
	//json.Unmarshal([]byte(`{"name":"polaris"}`), u1) 
	////以上会直接报错：panic: runtime error: invalid memory address or nil pointer dereference 
	//fmt.Printf("u1.Name=%+v/n", u1.Name) 
 
	var u2 *User 
	fmt.Printf("u2=%+v, &u2=%p/n", u2, &u2) //output: u2=<nil>, &u2=0xc00007a028 
	json.Unmarshal([]byte(`{"name":"polaris"}`), &u2) 
	fmt.Printf("u2.Name=%+v/n", u2.Name) //正常打印出u2.Name=polaris 
 
	/** 
	总结： 
		json.Unmarshal()第二个参数必须传入一个有内存地址的变量 
	*/ 
}