Package mongo 为 Go 提供了一个 MongoDB Driver API。

import “go.mongodb.org/mongo-driver/mongo” import “go.mongodb.org/mongo-driver/mongo/options”

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1 代码示例

  1. package main
  3. import (
  4.     "context"
  5.     "fmt"
  6.     "go.mongodb.org/mongo-driver/bson"
  7.     "go.mongodb.org/mongo-driver/mongo"
  8.     "go.mongodb.org/mongo-driver/mongo/options"
  9. )
  11. type User struct {
  12.     Name       string `bson:"name"`
  13.     Age        int    `bson:"age"`
  14.     BirthMonth int    `bson:"birth_month"`
  15.     gender     string `bson:"gender"`
  16. }
  18. // 新建MongoDB客户端对象
  19. func NewMongoClient() *mongo.Client {
  20.     clientOptions := options.Client().ApplyURI("mongodb://127.0.0.1:27017")
  21.     var err error
  22.     client, err := mongo.Connect(context.TODO(), clientOptions)
  23.     if err != nil {
  24.         fmt.Println(err)
  25.         return nil
  26.     }
  27.     // 检查是否连接正常
  28.     err = client.Ping(context.TODO(), nil)
  29.     if err != nil {
  30.         fmt.Println(err)
  31.         return nil
  32.     }
  33.     return client
  34. }
  36. // 单条插入
  37. func insertOne(c *mongo.Collection) {
  38.     res, _ := c.InsertOne(context.Background(), bson.M{"name": "ws1", "age": 19})
  39.     id := res.InsertedID
  40.     fmt.Println(id)
  41.     res, _ = c.InsertOne(context.Background(), bson.M{"name": "ws2", "age": 18})
  42.     id = res.InsertedID
  43.     fmt.Println(id)
  44. }
  46. // 多条插入
  47. func insertMany(c *mongo.Collection) {
  48.     c.InsertMany(context.Background(), []interface{}{
  49.         bson.M{"name": "ws3", "age": 19},
  50.         bson.M{"name": "ws4", "age": 18},
  51.         bson.M{"name": "ws5", "age": 17},
  52.         bson.M{"name": "ws6", "age": 18},
  53.     })
  54. }
  56. // 查找单条
  57. func findOne(c *mongo.Collection) {
  58.     singleResult := c.FindOne(context.Background(), bson.M{
  59.         "name": "ws1",
  60.     })
  61.     if singleResult == nil || singleResult.Err() != nil {
  62.         return
  63.     }
  64.     userData := User{}
  65.     err := singleResult.Decode(&userData)
  66.     if err != nil {
  67.         return
  68.     }
  69.     fmt.Println(userData)
  70. }
  72. // 查找多条
  73. func findMany(c *mongo.Collection) {
  74.     cursor, err := c.Find(context.Background(), bson.M{
  75.         "age": bson.M{"$lte": 18},
  76.     })
  77.     if err != nil {
  78.         return
  79.     }
  80.     for cursor.Next(context.Background()) {
  81.         userData := User{}
  82.         err := cursor.Decode(&userData)
  83.         if err != nil {
  84.             continue
  85.         }
  86.         fmt.Println(userData)
  87.     }
  88. }
  90. // 更新一条
  91. func updateOne(c *mongo.Collection) {
  92.     filter := bson.M{"name": "ws1"}
  93.     value := bson.M{"$set": bson.M{"age": 100}}
  94.     c.UpdateOne(context.Background(), filter, value)
  95. }
  97. // 更新多条
  98. func updateMany(c *mongo.Collection) {
  99.     filter := bson.M{"age": 18}
  100.     value := bson.M{"$set": bson.M{"age": 22}}
  101.     c.UpdateMany(context.Background(), filter, value)
  102. }
  104. // 分组查询
  105. func findGroup(c *mongo.Collection) {
  106.     // 复杂查询, 先匹配后分组
  107.     filter := bson.A{ // A表示Array
  108.         bson.M{
  109.             "$group": bson.M{
  110.                 "_id":           "$gender", // 按性别分组
  111.                 "minAge":        bson.M{"$min": "$age"},
  112.                 "maxBirthMonth": bson.M{"$max": "$birth_month"},
  113.             },
  114.         },
  115.     }
  116.     cursor, err := c.Aggregate(context.Background(), filter)
  117.     if err != nil {
  118.         fmt.Println(err)
  119.         return
  120.     }
  121.     for cursor.Next(context.Background()) {
  122.         doc := cursor.Current
  123.         // LookupErr取出key里的值
  124.         minAge, err2 := doc.LookupErr("minAge")
  125.         if err2 != nil {
  126.             return
  127.         }
  128.         fmt.Println(minAge) // {"$numberInt":"19"}
  130.         maxBirthMonth, err3 := doc.LookupErr("maxBirthMonth")
  131.         if err3 != nil {
  132.             return
  133.         }
  134.         fmt.Println(maxBirthMonth) // {"$numberDouble":"4.0"}
  136.     }
  137. }
  139. // 分页查询
  140. func findPage(c *mongo.Collection) {
  141.     filter := bson.M{"age": bson.M{"$lt": 50}}
  142.     cursor, err := c.Find(context.Background(), filter,
  143.         options.Find().SetSort(bson.D{{"age", -1}}),
  144.         options.Find().SetLimit(4),
  145.         options.Find().SetSkip(1))
  146.     if err != nil {
  147.         return
  148.     }
  149.     var users []User
  150.     err2 := cursor.All(context.Background(), &users)
  151.     if err2 != nil {
  152.         return
  153.     }
  154.     for _, user := range users {
  155.         fmt.Println(user.Name, user.Age)
  156.     }
  157. }
  159. func main() {
  160.     // 创建客户端对象
  161.     client := NewMongoClient()
  162.     // 创建集合对象
  163.     c := client.Database("wstest").Collection("users")
  164.     // 执行代码
  165.     findPage(c)
  166. }

2 json字符串 转 bson

  1. package main
  3. import (
  4.     "fmt"
  6.     "go.mongodb.org/mongo-driver/bson"
  7. )
  9. func main() {
  10.     var json = "{\"data\":1}"
  11.     var workflow interface{}
  12.     e := bson.UnmarshalExtJSON([]byte(json), false, &workflow)
  13.     if e != nil {
  14.         fmt.Println("err is ", e)
  15.         return
  16.     }
  17.     fmt.Println(workflow)
  19. }