ok:=i.(string);ok{fmt.Printf("i is a string: %s\n",s)}else{fmt.Println("i is not a string")}// 使用类型断言判断 i 的底层值是否为整数类型ifn,ok:=i.(int);ok{fmt.Printf("i is an integer: %d\n",n)}else{fmt.Println("i is not an in
// requires p.mu is held. func (p *clientConnPool) getStartDialLocked(addr string) *dialCall { // 判断正在连接,如果存在则返回这个连接dialCall if call, ok := p.dialing[addr]; ok { // A dial is already in-flight. Don't start another. return call } // 生成新的连接对象,进行返回...
typeRawErrorstruct{msgstring}func(e *RawError)Error()string{returne.msg}funcmain(){rawError := &RawError{msg:"no such file or directory"}fmt.Println("rawError:", rawError)wrapError := errors.Wrap(rawError,"a error occurred in xxxx,xxxxx")fmt.Println("wrapError:", wrapError)wrapwrapE...
="POST"{w.WriteHeader(http.StatusMethodNotAllowed)return}// Read the body into a string for json decodingvarcontent=&PayloadCollection{}err:=json.NewDecoder(io.LimitReader(r.Body,MaxLength)).Decode(&content)iferr!=nil{w.Header().Set("Content-Type","application/json; charset=UTF-8")w.Write...
var u *user = (*user)(nil) if u == nil { t.Log("u is nil") } else { t.Log("u is not nil") } // u is nil map 之坑 map 并发读写 map 并发读写会 panic, 需要加锁或者使用 sync.Map map 不能直接更新 value 的某一个字段 type User struct{ name string } func TestMap...
func IsRetryableErr(err error) bool { return errors.Is(err, ErrLockAcquiredByOthers) } // 基于 redis 实现的分布式锁,不可重入,但保证了对称性 type RedisLock struct { LockOptions key string token string client *Client } func NewRedisLock(key string, client *Client, opts ...LockOption) *...
Comment: 状态 0|正常、1|注销、2|冻结RegisterIPstring`gorm:"column:register_ip;not null;type:varchar;size:255;" json:"register_ip"`// Comment: no commentRegisterTimetime.Time`gorm:"column:register_time;not null;type:timestamp;size:64;default:CURRENT_TIMESTAMP;" json:"register_time"`// ...
m :=make(map[string]int,99)println(cap(m))// error: invalid argument m1 (type map[string]int) for cap} 11. string 类型的变量值不能为 nil 对那些喜欢用nil初始化字符串的人来说,这就是坑: // 错误示例funcmain(){varsstring=nil// cannot use nil as type string in assignmentifs ==nil...
values 用于保存注入的参数,是一个用 reflect.Type 当键、reflect.Value 为值的 map,理解这点将有助于理解 Map 和 MapTo。 type injector struct { values map[reflect.Type]reflect.Value parent Injector } // InterfaceOf dereferences a pointer to an Interface type. // It panics if value is not ...
This repository generally followsSemantic Versioning. However, the API client inprometheus/client_golang/api/…is still considered experimental. Breaking changes of the API client willnottrigger a new major release. The same is true for selected other new features explicitly marked asEXPERIMENTALin CHA...