使用Go語言訪問JSON數據(gojsonq)
主要是使用第三方的庫 gojsonq,來查詢JSON數據
例如這樣的JSON數據
{
"name":"computers",
"description":"List of computer products",
"vendor":{
"name":"Star Trek",
"email":"info@example.com",
"website":"www.example.com",
"items":[
{
"id":1,
"name":"MacBook Pro 13 inch retina",
"price":1350
},
{
"id":2,
"name":"MacBook Pro 15 inch retina",
"price":1700
},
{
"id":3,
"name":"Sony VAIO",
"price":1200
},
{
"id":4,
"name":"Fujitsu",
"price":850
},
{
"id":5,
"name":"HP core i5",
"price":850,
"key":2300
},
{
"id":6,
"name":"HP core i7",
"price":950
},
{
"id":null,
"name":"HP core i3 SSD",
"price":850
}
],
"prices":[
2400,
2100,
1200,
400.87,
89.90,
150.10
],
"names":[
"John Doe",
"Jane Doe",
"Tom",
"Jerry",
"Nicolas",
"Abby"
]
}
}
安裝導入 gojsonq
go get github.com/thedevsaddam/gojsonq
or
go get gopkg.in/thedevsaddam/gojsonq.v1
引入
import "github.com/thedevsaddam/gojsonq"
or
import "gopkg.in/thedevsaddam/gojsonq.v1"
可以像ORM訪問數據庫一樣，訪問JSON數據
簡單應用
package main
import (
"fmt"
"log"
"github.com/thedevsaddam/gojsonq"
)
func main() {
jq := gojsonq.New().File("./sample-data.json")
res := jq.Find("vendor.items.[1].name")
if jq.Error() != nil {
log.Fatal(jq.Error())
}
fmt.Println(res)
}
輸出結果
MacBook Pro 15 inch retina
Example 1
Query select * from vendor.items where price > 1200 or id null
使用 gojsonq 的方式查詢
func ex1(){
jq := gojsonq.New().File("./sample-data.json")
res := jq.From("vendor.items").Where("price", ">", 1200).OrWhere("id", "=", nil).Get()
fmt.Println(res)
}
輸出結果
[map[price:1350 id:1 name:MacBook Pro 13 inch retina] map[id:2 name:MacBook Pro 15 inch retina price:1700] map[id:<nil> name:HP core i3 SSD price:850]]
Example 2
Query select name,price from vendor.items where price > 1200 or id null
使用 gojsonq 的方式查詢
func ex2() {
jq := gojsonq.New().File("./sample-data.json")
res := jq.From("vendor.items").Where("price", ">", 1200).OrWhere("id", "=", nil).
Only("name", "price")
fmt.Println(res)
}
輸出結果
[map[name:MacBook Pro 13 inch retina price:1350] map[name:MacBook Pro 15 inch retina price:1700] map[name:HP core i3 SSD price:850]]
Example 3
Query select sum(price) from vendor.items where price > 1200 or id null
使用 gojsonq 的方式查詢
func ex3() {
jq := gojsonq.New().File("./sample-data.json")
res := jq.From("vendor.items").Where("price", ">", 1200).OrWhere("id", "=", nil).Sum("price")
fmt.Println(res)
}
輸出結果
3900
Example 4
Query select price from vendor.items where price > 1200
使用gojsonq的方式查詢
func ex4() {
jq := gojsonq.New().File("./sample-data.json")
res := jq.From("vendor.items").Where("price", ">", 1200).Pluck("price")
fmt.Println(res)
}
輸出結果
[1350 1700]
Example 5
Query select * from vendor.items order by price
使用gojsonq的方式查詢
func ex5() {
jq := gojsonq.New().File("./sample-data.json")
res := jq.From("vendor.items").SortBy("price").Get()
fmt.Println(res)
}
輸出結果
[map[id:<nil> name:HP core i3 SSD price:850] map[id:4 name:Fujitsu price:850] map[price:850 key:2300 id:5 name:HP core i5] map[id:6 name:HP core i7 price:950] map[name:Sony VAIO price:1200 id:3] map[id:1 name:MacBook Pro 13 inch retina price:1350] map[price:1700 id:2 name:MacBook Pro 15 inch retina]]
Example 6
處理相關的錯誤信息
func ex6() {
jq := gojsonq.New().File("./sample-data.txt")
err := jq.Error()
if err != nil {
log.Fatalln(err)
}
}
輸出結果
2019/01/01 11:20:42 gojsonq: open ./sample-data.txt: The system cannot find the file specified.
Example 7
如這樣的JSON數據
{
"users":[
{
"id":1,
"name":{
"first":"John",
"last":"Ramboo"
}
},
{
"id":2,
"name":{
"first":"Ethan",
"last":"Hunt"
}
},
{
"id":3,
"name":{
"first":"John",
"last":"Doe"
}
}
]
}
實現這樣的查詢 select * from users where name.first=John
使用 gojsonq 的方式查詢
func ex7() {
jq := gojsonq.New().File("./data.json")
res := jq.From("users").WhereEqual("name.first", "John").Get()
fmt.Println(res)
}
輸出結果
[map[id:1 name:map[first:John last:Ramboo]] map[id:3 name:map[first:John last:Doe]]]