Record the Go language mining pit and record the gob serialization pit.-Golang-php.cn

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package mainimport ( "bytes" "encoding/gob" "fmt" "log" "os")func main() { /// 序列化编码&写入文件开始 /// // 实例化一个学生对象s1 s1 := &Student{id: 1, name: "jack ma", age: 2, cash: 43242334.35} // 实例化一个gob编码对象，并对s1学生对象进行编码 var buf bytes.Buffer encoder := gob.NewEncoder(&buf) error2Log("Encode: ", encoder.Encode(s1)) // 输出序列化后的类容 fmt.Printf("Serialized: %x\n", buf.Bytes()) // 创建data.data文件，存放序列化数据 fs, err := os.Create("./data.data") error2Log("Creat File: ", err) // 写入数据，并打印写入数据长度 wlen, err := fs.Write(buf.Bytes()) error2Log("Write file: ", err) fmt.Println("Wirte bytes:", wlen) fs.Close() /// 序列化编码&写入文件结束 /// /// 读入文件&反序列化编码开始 /// // 从文件打开写入的序列化数据 fs, err = os.Open("./data.data") error2Log("Open file: ", err) // 获取文件信息接口 finfo, err := fs.Stat() error2Log("Get fileinfo: ", err) // 根据文件大小创建字节数组，然后将文件中数据读入到字节数组中，并打印读入数据长度 readBuf := make([]byte, finfo.Size()) rlen, err := fs.Read(readBuf) error2Log("Read file: ", err) fmt.Println("Read bytes:", rlen) fs.Close() // 实例化一个用于接收反序列化数据的学生对象 s2 := new(Student) // 实例化一个gob解码对象 decoder := gob.NewDecoder(bytes.NewReader(readBuf)) // 将数据解码到学生对象s2 error2Log("Decode: ", decoder.Decode(s2)) // 将反序列化后的数据，s2学生对象打印出来 fmt.Println("Unserialized：", s2) /// 读入文件&反序列化编码结束 ///}func error2Log(m string, e error) { if e != nil { log.Fatal(m, e) }}// Student 学生对象type Student struct { id uint64 name string age uint cash float64}

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The running structure after compilation is as follows:

2019/04/17 15:07:46 Encode: gob: type main.Student has no exported fields

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It made me depressed Many hours. I checked some information, such as:

https://github.com/golang/go/issues/5819
But this is not the solution to the problem I need. I just want to add one The structure object is written to the file, and there is no intention to embed the structure.
Then a sudden inspiration came to me, and I made a super low-level mistake:

type Student struct { id uint64 name string age uint cash float64}

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Nima... Structure members (called fields in Golang) are lowercase..., and suddenly I remembered about package-level variable names and function names, Lowercase is equivalent to private... Is that so?
Immediately changed:

type Student struct { ID uint64 Name string Age uint Cash float64}

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The instantiation s1 in line 14 was changed to:

s1 := &Student{ID: 1, Name: "jack ma", Age: 2, Cash: 43242334.35}

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Then the compile and run structure was finally correct:

Serialized: 36ff810301010753747564656e7401ff820001040102494401060001044e616d65010c00010341676501060001044361736801080000001aff82010101076a61636b206d61010201f8cdccccf29a9e844100 Wirte bytes: 82 Read bytes: 82 Unserialized： &{1 jack ma 2 4.324233435e+07}

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This is equivalent to going back It seems that there are no coding habits developed in golang.
Therefore, when writing structures in the future, you must develop a good habit: field names should use capital letters. (555555555555555~)

package mainimport ( "bytes" "encoding/gob" "fmt" "log" "os")func main() { /// 序列化编码&写入文件开始 /// // 实例化一个学生对象s1 s1 := &Student{id: 1, name: "jack ma", age: 2, cash: 43242334.35} // 实例化一个gob编码对象，并对s1学生对象进行编码 var buf bytes.Buffer encoder := gob.NewEncoder(&buf) error2Log("Encode: ", encoder.Encode(s1)) // 输出序列化后的类容 fmt.Printf("Serialized: %x\n", buf.Bytes()) // 创建data.data文件，存放序列化数据 fs, err := os.Create("./data.data") error2Log("Creat File: ", err) // 写入数据，并打印写入数据长度 wlen, err := fs.Write(buf.Bytes()) error2Log("Write file: ", err) fmt.Println("Wirte bytes:", wlen) fs.Close() /// 序列化编码&写入文件结束 /// /// 读入文件&反序列化编码开始 /// // 从文件打开写入的序列化数据 fs, err = os.Open("./data.data") error2Log("Open file: ", err) // 获取文件信息接口 finfo, err := fs.Stat() error2Log("Get fileinfo: ", err) // 根据文件大小创建字节数组，然后将文件中数据读入到字节数组中，并打印读入数据长度 readBuf := make([]byte, finfo.Size()) rlen, err := fs.Read(readBuf) error2Log("Read file: ", err) fmt.Println("Read bytes:", rlen) fs.Close() // 实例化一个用于接收反序列化数据的学生对象 s2 := new(Student) // 实例化一个gob解码对象 decoder := gob.NewDecoder(bytes.NewReader(readBuf)) // 将数据解码到学生对象s2 error2Log("Decode: ", decoder.Decode(s2)) // 将反序列化后的数据，s2学生对象打印出来 fmt.Println("Unserialized：", s2) /// 读入文件&反序列化编码结束 ///}func error2Log(m string, e error) { if e != nil { log.Fatal(m, e) }}// Student 学生对象type Student struct { id uint64 name string age uint cash float64}

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The running structure after compilation is as follows:

2019/04/17 15:07:46 Encode: gob: type main.Student has no exported fields

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It made me depressed for more than an hour . I queried some information, such as:

https://github.com/golang/go/issues/5819
But this is not the solution to the problem I need. I just want to write a structure object to a file. There is no intention to embed the structure into it.
Then a sudden inspiration came to me, and I made a super low-level mistake:

type Student struct { id uint64 name string age uint cash float64}

Copy after login

Immediately changed:

type Student struct { ID uint64 Name string Age uint Cash float64}

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The instantiation s1 in line 14 was changed to:

s1 := &Student{ID: 1, Name: "jack ma", Age: 2, Cash: 43242334.35}

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Then the compile and run structure was finally correct:

Serialized: 36ff810301010753747564656e7401ff820001040102494401060001044e616d65010c00010341676501060001044361736801080000001aff82010101076a61636b206d61010201f8cdccccf29a9e844100 Wirte bytes: 82 Read bytes: 82 Unserialized： &{1 jack ma 2 4.324233435e+07}

Copy after login

This is equivalent to going back It seems that there are no coding habits developed in golang.

Therefore, when writing structures in the future, you must develop a good habit: field names should use capital letters. (555555555555555~)

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