读取将r中的结构化二进制数据读入数据。 数据必须是指向固定大小值或固定大小值切片的指针。 从r读取的字节使用指定的字节顺序进行解码,并写入数据的连续字段。 当解码布尔值时,零字节被解码为假,而且任何其余非零字节被解码为真。 读入结构时,将跳过具备空白(_)字段名称的字段的字段数据; 即,空白字段名称可用于填充。 读入结构时,必须导出全部非空白字段,不然“读取”可能会出现混乱。函数
可是这种只能使用固定大小类型的数据,变长数据就会异常,例如string, slice 等ui
package main import ( "bytes" "encoding/binary" "fmt" ) type T struct { A int64 B float64 } func main() { // Create a struct and write it. t := T{A: 0xEEFFEEFF, B: 3.14} buf := &bytes.Buffer{} err := binary.Write(buf, binary.BigEndian, t) if err != nil { panic(err) } fmt.Println(buf.Bytes()) // Read into an empty struct. t = T{} err = binary.Read(buf, binary.BigEndian, &t) if err != nil { panic(err) } fmt.Printf("%x %f", t.A, t.B) }
使用 unsafe 包编码
ByteToStruct指针
package main import ( "fmt" "unsafe" ) type TestStructTobytes struct { data int64 } type SliceMock struct { addr uintptr len int cap int } func main() { var testStruct = &TestStructTobytes{100} Len := unsafe.Sizeof(*testStruct) testBytes := &SliceMock{ addr: uintptr(unsafe.Pointer(testStruct)), cap: int(Len), len: int(Len), } data := *(*[]byte)(unsafe.Pointer(testBytes)) fmt.Println("[]byte is : ", data) var ptestStruct *TestStructTobytes = *(**TestStructTobytes)(unsafe.Pointer(&data)) fmt.Println("ptestStruct.data is : ", ptestStruct.data) }
StructToBytecode
package main import ( "fmt" "unsafe" ) type TestStructTobytes struct { data int64 } type SliceMock struct { addr uintptr len int cap int } func main() { var testStruct = &TestStructTobytes{100} Len := unsafe.Sizeof(*testStruct) testBytes := &SliceMock{ addr: uintptr(unsafe.Pointer(testStruct)), cap: int(Len), len: int(Len), } data := *(*[]byte)(unsafe.Pointer(testBytes)) fmt.Println("[]byte is : ", data) }
只使用于客户端服务端都使用gob包进行编码和解码的状况。也就是客户端服务端都是go写的,不试用于多种语言。接口
Gob流不支持函数和通道。试图在最顶层编码这些类型的值会致使失败。结构体中包含函数或者通道类型的字段的话,会视做非导出字段(忽略)处理。three
Gob能够编码任意实现了GobEncoder接口或者encoding.BinaryMarshaler接口的类型的值(经过调用对应的方法),GobEncoder接口优先。ip
Gob能够解码任意实现了GobDecoder接口或者encoding.BinaryUnmarshaler接口的类型的值(经过调用对应的方法),一样GobDecoder接口优先。get
package main import ( "bytes" "encoding/gob" "fmt" ) // A struct with a mix of fields, used for the GOB example. type complexData struct { N int S string M map[string]int P []byte C *complexData E Addr } type Addr struct { Comment string } func main() { testStruct := complexData{ N: 23, S: "string data", M: map[string]int{"one": 1, "two": 2, "three": 3}, P: []byte("abc"), C: &complexData{ N: 256, S: "Recursive structs? Piece of cake!", M: map[string]int{"01": 1, "10": 2, "11": 3}, E: Addr{ Comment: "InnerTest123123123123", }, }, E: Addr{ Comment: "Test123123123", }, } fmt.Println("Outer complexData struct: ", testStruct) fmt.Println("Inner complexData struct: ", testStruct.C) fmt.Println("Inner complexData struct: ", testStruct.E) fmt.Println("===========================") var b bytes.Buffer enc := gob.NewEncoder(&b) err := enc.Encode(testStruct) if err != nil { fmt.Println(err) } dec := gob.NewDecoder(&b) var data complexData err = dec.Decode(&data) if err != nil { fmt.Println("Error decoding GOB data:", err) return } fmt.Println("Outer complexData struct: ", data) fmt.Println("Inner complexData struct: ", data.C) fmt.Println("Inner complexData struct: ", testStruct.E) }
[译]Go里面的unsafe包详解string