Go 手动读取 json（pull 方式）

jsoniter 库

jsoniter 能以极低的成本，替换标准库，性能明显高于标准库。

同时，jsoniter 也可以手动解析 json，灵活度更高。

安装 jsoniter：

go get github.com/json-iterator/go

导入 jsoniter：

import (
	// ...
	jsoniter "github.com/json-iterator/go"
)

手动解析

解析 object

func main() {
	iter := jsoniter.ParseString(jsoniter.ConfigDefault, `
{
  "name": "Cake",
  "weight": 150,
  "price": 18.8
}
`)
	for field := iter.ReadObject(); field != ""; field = iter.ReadObject() {
		switch field {
		case "name":
			name := iter.ReadString()
			fmt.Printf("name: %s\n", name)
		case "price":
			price := iter.ReadFloat32()
			fmt.Printf("price: %.2f\n", price)
		default:
			iter.Skip()
		}
	}
}

output:

name: Cake
price: 18.80

解析 array

func main() {
	iter := jsoniter.ParseString(jsoniter.ConfigDefault, `
[
  {
    "name": "Cake",
    "price": 18.8,
    "weight": 150
  },
  {
    "name": "Sugar",
    "price": 7.5,
    "weight": 500
  }
]
`)
	for iter.ReadArray() {
		for field := iter.ReadObject(); field != ""; field = iter.ReadObject() {
			switch field {
			case "name":
				name := iter.ReadString()
				fmt.Printf("name: %s\n", name)
			case "price":
				price := iter.ReadFloat32()
				fmt.Printf("price: %.2f\n", price)
			default:
				iter.Skip()
			}
		}
	}
}

output：

name: Cake
price: 18.80
name: Sugar
price: 7.50