使用Golang将MySQL表转储为JSON

Question

在Go中将MySQL的快速转储器放到了JSON中.但是我发现从数据库中检索的所有内容都是[]byte数组.因此,我将所有内容编码为字符串,而不是原生的JSON整数或布尔值.

代码子集:

import (
    "encoding/json"
    "database/sql"
    _ "github.com/go-sql-driver/mysql"
)


func dumpTable(w io.Writer, table) {
    // ...

    rows, err := Query(db, fmt.Sprintf("SELECT * FROM %s", table))
    checkError(err)
    columns, err := rows.Columns()
    checkError(err)

    scanArgs := make([]interface{}, len(columns))
    values   := make([]interface{}, len(columns))

    for i := range values {
        scanArgs[i] = &values[i]
    }

    for rows.Next() {
        err = rows.Scan(scanArgs...)
        checkError(err)

        record := make(map[string]interface{})

        for i, col := range values {
            if col != nil {
                fmt.Printf("\n%s: type= %s\n", columns[i], reflect.TypeOf(col))

                switch t := col.(type) {
                default:
                    fmt.Printf("Unexpected type %T\n", t)
                case bool:
                    fmt.Printf("bool\n")
                    record[columns[i]] = col.(bool)
                case int:
                    fmt.Printf("int\n")
                    record[columns[i]] = col.(int)
                case int64:
                    fmt.Printf("int64\n")
                    record[columns[i]] = col.(int64)
                case float64:
                    fmt.Printf("float64\n")
                    record[columns[i]] = col.(float64)
                case string:
                    fmt.Printf("string\n")
                    record[columns[i]] = col.(string)
                case []byte:   // -- all cases go HERE!
                    fmt.Printf("[]byte\n")
                    record[columns[i]] = string(col.([]byte))
                case time.Time:
                    // record[columns[i]] = col.(string)
                }
            }
        }

        s, _ := json.Marshal(record)
        w.Write(s)
        io.WriteString(w, "\n")
    }
}

Answer 1

我还需要转储数据库表JSON和这里是我如何实现:(比本主题中另一个答案不同,一切都不是字符串,感谢这样的回答:/sf/answers/1251994551/,我可以正确获取整数字段)

func getJSON(sqlString string) (string, error) {
    rows, err := db.Query(sqlString)
    if err != nil {
        return "", err
    }
    defer rows.Close()
    columns, err := rows.Columns()
    if err != nil {
        return "", err
    }
    count := len(columns)
    tableData := make([]map[string]interface{}, 0)
    values := make([]interface{}, count)
    valuePtrs := make([]interface{}, count)
    for rows.Next() {
        for i := 0; i < count; i++ {
          valuePtrs[i] = &values[i]
        }
        rows.Scan(valuePtrs...)
        entry := make(map[string]interface{})
        for i, col := range columns {
            var v interface{}
            val := values[i]
            b, ok := val.([]byte)
            if ok {
                v = string(b)
            } else {
                v = val
            }
            entry[col] = v
        }
        tableData = append(tableData, entry)
    }
    jsonData, err := json.Marshal(tableData)
    if err != nil {
        return "", err
    }
    fmt.Println(string(jsonData))
    return string(jsonData), nil 
}

以下是示例输出:[{"ID":0,"文本":"零"},{"ID":1,"文本":"一个"},{"ID":2,"文本": "二"}]