package main    import (      "fmt"      "launchpad.net/mgo"      "launchpad.net/mgo/bson"  )    type Mail struct {      Id bson.ObjectId "_id"      Name string      Email string  }    func main() {      // 连接数据库      session, err := mgo.Dial("127.0.0.1")      if err != nil {          panic(err)      }      defer session.Close()        // 获取数据库,获取集合      c := session.DB("test").C("mail")        // 存储数据      m1 := Mail{bson.NewObjectId(), "user1", "user1@dotcoo.com"}      m2 := Mail{bson.NewObjectId(), "user1", "user2@dotcoo.com"}      m3 := Mail{bson.NewObjectId(), "user3", "user3@dotcoo.com"}      m4 := Mail{bson.NewObjectId(), "user3", "user4@dotcoo.com"}      err = c.Insert(&m1, &m2, &m3, &m4)      if err != nil {          panic(err)      }        // 读取数据      ms := []Mail{}      err = c.Find(&bson.M{"name":"user3"}).All(&ms)      if err != nil {          panic(err)      }        // 显示数据      for i, m := range ms {          fmt.Printf("%s, %d, %s\n", m.Id.Hex(), i, m.Email)      }  }