简介
easyjson是什么呢？ 根据官网介绍，easyjson是提供高效快速且易用的结构体structs<-->json转换包。easyjson并没有使用反射方式实现，所以性能比其他的json包该4-5倍，比golang 自带的json包快2-3倍。 easyjson目标是维持生成去代码简单，以致于它可以轻松地进行优化或固定。
安装
go get -u github.com/mailru/easyjson/
go install github.com/mailru/easyjson/easyjson
or
go build -o easyjson github.com/mailru/easyjson/easyjson
验证是否安装成功。
$ easyjson
Usage of D:\Code\go\bin\easyjson.exe:
-all
generate marshaler/unmarshalers for all structs in a file
-build_tags string
build tags to add to generated file
-leave_temps
do not delete temporary files
-lower_camel_case
use lowerCamelCase names instead of CamelCase by default
-no_std_marshalers
don't generate MarshalJSON/UnmarshalJSON funcs
-noformat
do not run 'gofmt -w' on output file
-omit_empty
omit empty fields by default
string
specify the filename of the output
-pkg
process the whole package instead of just the given file
-snake_case
use snake_case names instead of CamelCase by default
-stubs
only generate stubs for marshaler/unmarshaler funcs
其中有几个选项需要注意：
-lower_camel_case:将结构体字段field首字母改为小写。如Name=>name。
-build_tags string:将指定的string生成到生成的go文件头部。
-no_std_marshalers：不为结构体生成MarshalJSON/UnmarshalJSON函数。
-omit_empty:没有赋值的field可以不生成到json，否则field为该字段类型的默认值。
-output_filename:定义生成的文件名称。
-pkg:对包内指定有`//easyjson:json`结构体生成对应的easyjson配置。
-snke_case:可以下划线的field如`Name_Student`改为`name_student`。
使用
记得在需要使用easyjson的结构体上加上//easyjson:json。
如下：
//easyjson:json
type School struct {
Name string `json:"name"`
Addr string `json:"addr"`
}
//easyjson:json
type Student struct {
Id int `json:"id"`
Name string `json:"s_name"`
School School `json:"s_chool"`
Birthday time.Time `json:"birthday"`
}
在结构体包下执行
easyjson -all student.go
此时在该目录下出现一个新的文件。
// Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
package easyjson
import (
json "encoding/json"
easyjson "github.com/mailru/easyjson"
jlexer "github.com/mailru/easyjson/jlexer"
jwriter "github.com/mailru/easyjson/jwriter"
)
// suppress unused package warning
var (
_ *json.RawMessage
_ *jlexer.Lexer
_ *jwriter.Writer
_ easyjson.Marshaler
)
func easyjsonB83d7b77DecodeStudygoEasyjson(in *jlexer.Lexer, out *Student) {
isTopLevel := in.IsStart()
if in.IsNull() {
if isTopLevel {
in.Consumed()
}
in.Skip()
return
}
in.Delim('{')
for !in.IsDelim('}') {
key := in.UnsafeString()
in.WantColon()
if in.IsNull() {
in.Skip()
in.WantComma()
continue
}
switch key {
case "id":
out.Id = int(in.Int())
case "s_name":
out.Name = string(in.String())
case "s_chool":
easyjsonB83d7b77DecodeStudygoEasyjson1(in, &out.School)
case "birthday":
if data := in.Raw(); in.Ok() {
in.AddError((out.Birthday).UnmarshalJSON(data))
}
default:
in.SkipRecursive()
}
in.WantComma()
}
in.Delim('}')
if isTopLevel {
in.Consumed()
}
}
func easyjsonB83d7b77EncodeStudygoEasyjson(out *jwriter.Writer, in Student) {
out.RawByte('{')
first := true
_ = first
if !first {
out.RawByte(',')
}
first = false
out.RawString("\"id\":")
out.Int(int(in.Id))
if !first {
out.RawByte(',')
}
first = false
out.RawString("\"s_name\":")
out.String(string(in.Name))
if !first {
out.RawByte(',')
}
first = false
out.RawString("\"s_chool\":")
easyjsonB83d7b77EncodeStudygoEasyjson1(out, in.School)
if !first {
out.RawByte(',')
}
first = false
out.RawString("\"birthday\":")
out.Raw((in.Birthday).MarshalJSON())
out.RawByte('}')
}
// MarshalJSON supports json.Marshaler interface
func (v Student) MarshalJSON() ([]byte, error) {
w := jwriter.Writer{}
easyjsonB83d7b77EncodeStudygoEasyjson(&w, v)
return w.Buffer.BuildBytes(), w.Error
}
// MarshalEasyJSON supports easyjson.Marshaler interface
func (v Student) MarshalEasyJSON(w *jwriter.Writer) {
easyjsonB83d7b77EncodeStudygoEasyjson(w, v)
}
// UnmarshalJSON supports json.Unmarshaler interface
func (v *Student) UnmarshalJSON(data []byte) error {
r := jlexer.Lexer{Data: data}
easyjsonB83d7b77DecodeStudygoEasyjson(&r, v)
return r.Error()
}
// UnmarshalEasyJSON supports easyjson.Unmarshaler interface
func (v *Student) UnmarshalEasyJSON(l *jlexer.Lexer) {
easyjsonB83d7b77DecodeStudygoEasyjson(l, v)
}
func easyjsonB83d7b77DecodeStudygoEasyjson1(in *jlexer.Lexer, out *School) {
isTopLevel := in.IsStart()
if in.IsNull() {
if isTopLevel {
in.Consumed()
}
in.Skip()
return
}
in.Delim('{')
for !in.IsDelim('}') {
key := in.UnsafeString()
in.WantColon()
if in.IsNull() {
in.Skip()
in.WantComma()
continue
}
switch key {
case "name":
out.Name = string(in.String())
case "addr":
out.Addr = string(in.String())
default:
in.SkipRecursive()
}
in.WantComma()
}
in.Delim('}')
if isTopLevel {
in.Consumed()
}
}
func easyjsonB83d7b77EncodeStudygoEasyjson1(out *jwriter.Writer, in School) {
out.RawByte('{')
first := true
_ = first
if !first {
out.RawByte(',')
}
first = false
out.RawString("\"name\":")
out.String(string(in.Name))
if !first {
out.RawByte(',')
}
first = false
out.RawString("\"addr\":")
out.String(string(in.Addr))
out.RawByte('}')
}
现在可以写一个测试类啦。
package main
import (
"studygo/easyjson"
"time"
"fmt"
)
func main(){
s:=easyjson.Student{
Id: 11,
Name:"qq",
School:easyjson.School{
Name:"CUMT",
Addr:"xz",
},
Birthday:time.Now(),
}
bt,err:=s.MarshalJSON()
fmt.Println(string(bt),err)
json:=`{"id":11,"s_name":"qq","s_chool":{"name":"CUMT","addr":"xz"},"birthday":"2017-08-04T20:58:07.9894603+08:00"}`
ss:=easyjson.Student{}
ss.UnmarshalJSON([]byte(json))
fmt.Println(ss)
}
运行结果：
{"id":11,"s_name":"qq","s_chool":{"name":"CUMT","addr":"xz"},"birthday":"2017-08-04T20:58:07.9894603+08:00"} <nil>
{121 {CwwwwwwwUMT xzwwwww} 2017-08-04 20:52:03.4066002 +0800 CST}
性能测试对比
Benchmark Results
ffjson results are from February 4th, 2016, using the latest ffjson and go1.6.
go/codec results are from March 4th, 2016, using the latest go/codec and go1.6.
Unmarshaling
| lib | json size | MB/s | allocs/op | B/op | |:---------|:----------|-----:|----------:|------:| | standard | regular | 22 | 218 | 10229 | | standard | small | 9.7 | 14 | 720 | | | | | | | | easyjson | regular | 125 | 128 | 9794 | | easyjson | small | 67 | 3 | 128 | | | | | | | | ffjson | regular | 66 | 141 | 9985 | | ffjson | small | 17.6 | 10 | 488 | | | | | | | | codec | regular | 55 | 434 | 19299 | | codec | small | 29 | 7 | 336 | | | | | | | | ujson | regular | 103 | N/A | N/A |
Marshaling, one goroutine.
| lib | json size | MB/s | allocs/op | B/op | |:----------|:----------|-----:|----------:|------:| | standard | regular | 75 | 9 | 23256 | | standard | small | 32 | 3 | 328 | | standard | large | 80 | 17 | 1.2M | | | | | | | | easyjson | regular | 213 | 9 | 10260 | | easyjson* | regular | 263 | 8 | 742 | | easyjson | small | 125 | 1 | 128 | | easyjson | large | 212 | 33 | 490k | | easyjson* | large | 262 | 25 | 2879 | | | | | | | | ffjson | regular | 122 | 153 | 21340 | | ffjson** | regular | 146 | 152 | 4897 | | ffjson | small | 36 | 5 | 384 | | ffjson** | small | 64 | 4 | 128 | | ffjson | large | 134 | 7317 | 818k | | ffjson** | large | 125 | 7320 | 827k | | | | | | | | codec | regular | 80 | 17 | 33601 | | codec*** | regular | 108 | 9 | 1153 | | codec | small | 42 | 3 | 304 | | codec*** | small | 56 | 1 | 48 | | codec | large | 73 | 483 | 2.5M | | codec*** | large | 103 | 451 | 66007 | | | | | | | | ujson | regular | 92 | N/A | N/A |
* marshaling to a writer,
** using ffjson.Pool(),
*** reusing output slice instead of resetting it to nil
Marshaling, concurrent.
| lib | json size | MB/s | allocs/op | B/op | |:----------|:----------|-----:|----------:|------:| | standard | regular | 252 | 9 | 23257 | | standard | small | 124 | 3 | 328 | | standard | large | 289 | 17 | 1.2M | | | | | | | | easyjson | regular | 792 | 9 | 10597 | | easyjson* | regular | 1748 | 8 | 779 | | easyjson | small | 333 | 1 | 128 | | easyjson | large | 718 | 36 | 548k | | easyjson* | large | 2134 | 25 | 4957 | | | | | | | | ffjson | regular | 301 | 153 | 21629 | | ffjson** | regular | 707 | 152 | 5148 | | ffjson | small | 62 | 5 | 384 | | ffjson** | small | 282 | 4 | 128 | | ffjson | large | 438 | 7330 | 1.0M | | ffjson** | large | 131 | 7319 | 820k | | | | | | | | codec | regular | 183 | 17 | 33603 | | codec*** | regular | 671 | 9 | 1157 | | codec | small | 147 | 3 | 304 | | codec*** | small | 299 | 1 | 48 | | codec | large | 190 | 483 | 2.5M | | codec*** | large | 752 | 451 | 77574 |
* marshaling to a writer,
** using ffjson.Pool(),
*** reusing output slice instead of resetting it to nil
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