迭代MySQL记录并在GoLang中创建JSON

Question

I'm trying to read data from a MySQL database from my Go app.

var queryStr string = "SELECT * FROM Customers"
rows, err := db.Query(queryStr)

defer rows.Close()
for rows.Next() {
    // do stuffs
}

The query it's ok and it works; now I'd like to easily map each record of the MySQL query to a Customer object that I've previuosly defined as showed below:

type Customer struct {
    id              IntegerType     `json:"id"`
    name            string          `json:"name"`
    surname         string          `json:"surname"`
}

How can I do that?

Second question: once I get an array of Customer object how can I easily put it into a new JSON object under a specific key called "data"?

thanks for your support :)

Answer 1

Export fields so they can be used on JSON:

type Customer struct {
   ID      int         `json:"id"`
   Name    string      `json:"name"`
   Surname string      `json:"surname"`
}

Declare a value to be marshaled to JSON:

var v struct {
    Data []Customer `json:"data"`
}

Query for the specific fields:

var queryStr string = "SELECT id, name, surname FROM Customers"
rows, err := db.Query(queryStr)

Loop through rows adding to value.

defer rows.Close()
for rows.Next() {
    // Scan one customer record
    var c Customer
    if err := rows.Scan(&c.ID, &c.Name, &c.Surnmae); err != nil {
        // handle error
    }
    v.Data = append(v.Data, c)
}
if rows.Err() != nil {
    // handle error
}

Marshal the value to JSON

p, err := json.Marshal(v)
if err != nil {
    // handle error
}

The value p is a []byte containing the JSON.