How to Handle `json:'omitempty'` with `time.Time` Fields in Go?

JSON omitempty with time.Time Field

In Go, the json,omitempty" annotation allows you to exclude fields with empty values from JSON serialization. However, this doesn't work with time.Time fields as they have a zero value that is considered a valid date.

To resolve this issue, set the time.Time field to time.Time{} instead of leaving it as a zero value. This will instruct the JSON encoder to treat the field as empty.

Consider the following example:

package main

import (
    "encoding/json"
    "fmt"
    "time"
)

type MyStruct struct {
    Timestamp time.Time `json:",omitempty"`
    Date      time.Time `json:",omitempty"`
    Field     string    `json:",omitempty"`
}

func main() {
    ms := MyStruct{
        Timestamp: time.Date(2015, 9, 18, 0, 0, 0, 0, time.UTC),
        Date:      time.Time{},
        Field:     "",
    }

    bb, err := json.Marshal(ms)
    if err != nil {
        panic(err)
    }
    fmt.Println(string(bb))
}

Output:

{"Timestamp":"2015-09-18T00:00:00Z"}

Alternatively, you can use a pointer to time.Time and set it to nil to achieve the same effect:

type MyStruct struct {
    Timestamp *time.Time `json:",omitempty"`
    Date      *time.Time `json:",omitempty"`
    Field     string    `json:",omitempty"`
}

The above is the detailed content of How to Handle `json:'omitempty'` with `time.Time` Fields in Go?. For more information, please follow other related articles on the PHP Chinese website!