golang中gjson
开始
$ go get -u github.com/tidwall/gjson
JSON串
获取值
Get查询指定路径, 通过.来区分. 比如"name.last"或者"age". 如果找到了匹配路径, 将返回结果.
同时有 GetMany 方法批量获取值, 也有 GetBytes 方法获取字节切片.
package main
import "github.com/tidwall/gjson"
const json = `{"name":{"first":"Janet","last":"Prichard"},"age":47}`
func main() {
value := gjson.Get(json, "name.last")
println(value.String())
results := gjson.GetMany(json, "name.last", "age")
for _, result := range results {
println(result.String())
}
value = gjson.GetBytes([]byte(json), "name.last")
println(value.String())
}
遍历
例1.
package main
import "github.com/tidwall/gjson"
const json1 = `{"name":{"name":"zhangsan","age":47},"name1":{"name":"lisi","age":42}}`
func main() {
gjson.Get(json1, "name1").ForEach(printKeyValue())
}
func printKeyValue() func(key gjson.Result, value gjson.Result) bool {
return func(key, value gjson.Result) bool {
println(key.String(), ":", value.String())
return true
}
}
例2.
package main
import "github.com/tidwall/gjson"
const json = `{"name":"zhangsan","age":47}`
func main() {
gjson.Parse(json).ForEach(printKeyValue())
}
func printKeyValue() func(key gjson.Result, value gjson.Result) bool {
return func(key, value gjson.Result) bool {
println(key.String(), ":", value.String())
return true
}
}
JSON数组
获取值
例1.
package main
import "github.com/tidwall/gjson"
const jsonArray = `{
"names": [
{
"name": "zhangsan"
},
{
"name": "lisi"
}
]
}`
func main() {
value := gjson.Get(jsonArray, "names.0.name")
println(value.String())
value = gjson.Get(jsonArray, "names.1.name")
println(value.String())
}
例2.
package main
import (
"fmt"
"github.com/tidwall/gjson"
)
const jsonArray = `[
{
"name": "zhangsan",
"address": "beijing"
},
{
"name": "lisi",
"address": "tianjin"
}
]
`
func main() {
valur := gjson.Get(jsonArray, "0.name")
fmt.Println(valur.String())
}
遍历
例1.
package main
import (
"fmt"
"github.com/tidwall/gjson"
)
const jsonArray = `{
"names": [
{
"name": "zhangsan",
"address": "beijing"
},
{
"name": "lisi",
"address": "tianjin"
}
]
}`
func main() {
for _, res := range gjson.Get(jsonArray, "names").Array() {
res.ForEach(func(key, value gjson.Result) bool {
fmt.Println(key.String(), ":", value.String())
return true
})
}
}
例2.
package main
import (
"fmt"
"github.com/tidwall/gjson"
)
const jsonArray = `[
{
"name": "zhangsan",
"address": "beijing"
},
{
"name": "lisi",
"address": "tianjin"
}
]
`
func main() {
for _, res := range gjson.Parse(jsonArray).Array() {
res.ForEach(func(key, value gjson.Result) bool {
fmt.Println(key.String(), ":", value.String())
return true
})
}
}
路径解析
- 路径是一系列被.分隔的key拼接而成.
- 路径可能包含通配符'*'和'?'.
- 通过下标访问数组值.
- 通过'#'来获取值在元素中的排位或访问子路径.
- .和通配符可以通过''来转义.
{
"name": {"first": "Tom", "last": "Anderson"},
"age":37,
"children": ["Sara","Alex","Jack"],
"fav.movie": "Deer Hunter",
"friends": [
{"first": "Dale", "last": "Murphy", "age": 44},
{"first": "Roger", "last": "Craig", "age": 68},
{"first": "Jane", "last": "Murphy", "age": 47}
]
}
"name.last" >> "Anderson"
"age" >> 37
"children" >> ["Sara","Alex","Jack"]
"children.#" >> 3
"children.1" >> "Alex"
"child*.2" >> "Jack"
"c?ildren.0" >> "Sara"
"fav\.movie" >> "Deer Hunter"
"friends.#.first" >> ["Dale","Roger","Jane"]
"friends.1.last" >> "Craig"
同样能通过#[...]来查询数组中的第一个匹配的项, 或通过'#[...]#'查询所有匹配的项.
查询支持==, !=, <, <=, >, >=比较运算符和'%'模糊匹配.
friends.#[last=="Murphy"].first >> "Dale"
friends.#[last=="Murphy"]#.first >> ["Dale","Jane"]
friends.#[age>45]#.last >> ["Craig","Murphy"]
friends.#[first%"D*"].last >> "Murphy"
JSON行
同样支持JSON Lines, 使用 .. 前缀, 把多行文档视作数组.
比如:
{"name": "Gilbert", "age": 61}
{"name": "Alexa", "age": 34}
{"name": "May", "age": 57}
{"name": "Deloise", "age": 44}
..# >> 4
..1 >> {"name": "Alexa", "age": 34}
..3 >> {"name": "Deloise", "age": 44}
..#.name >> ["Gilbert","Alexa","May","Deloise"]
..#[name="May"].age >> 57
ForEachLines 方法可以迭代json.
例1.
package main
import "github.com/tidwall/gjson"
const jsonRow = `{"name": "Gilbert", "age": 61}
{"name": "Alexa", "age": 34}
{"name": "May", "age": 57}
{"name": "Deloise", "age": 44}`
func main() {
println(gjson.Get(jsonRow, "..1").String())
}
例2.
package main
import "github.com/tidwall/gjson"
const jsonRow = `{"name": "Gilbert", "age": 61}
{"name": "Alexa", "age": 34}
{"name": "May", "age": 57}
{"name": "Deloise", "age": 44}`
func main() {
gjson.ForEachLine(jsonRow, func(line gjson.Result) bool {
println(line.Get("name").String())
return true
})
}
有疑问加站长微信联系（非本文作者）
