从0开始开发自己的BTC钱包：发送btc交易

// balanceCmd 命令主入口
func (c *WalletCommand) balanceCmd() *cobra.Command {
	balanceCmd := &cobra.Command{
		Use:   "balance",
		Short: "Get the balance of the wallet",
		Long:  "Get the balance of the wallet",
	}
	balanceCmd.AddCommand(c.getBalanceCmd())
	return balanceCmd
}

// getBalanceCmd 获取余额命令
func (c *WalletCommand) getBalanceCmd() *cobra.Command {
	return &cobra.Command{
		Use:   "get",
		Short: "Get the balance of the wallet",
		Long:  "Get the balance of the wallet, example: ./wallet balance network[testnet|mainnet] address",
		RunE:  c.runGetBalanceCmd,
	}
}

// runGetBalanceCmd 执行获取余额命令
func (c *WalletCommand) runGetBalanceCmd(cmd *cobra.Command, args []string) error {
	fmt.Println("get balance")

	utxos, err := getUTXOs(args[1], args[0])
	if err != nil {
		return errors.Wrap(err, "get utxos failed")
	}
	balance := 0.0
	for _, utxo := range utxos {
		balance += utxo.Amount
	}
	fmt.Printf("Address: %s Balance: %.9f BTC\n", args[1], balance)
	return nil
}

// txCmd 命令主入口
func (c *WalletCommand) txCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:   "tx",
		Short: "Transaction operations",
		Long:  "Transaction operations",
	}
	cmd.AddCommand(c.sendCmd())
	return cmd
}

// sendCmd 发送交易命令
func (c *WalletCommand) sendCmd() *cobra.Command {
	return &cobra.Command{
		Use:   "send",
		Short: "Send bitcoins, example: ./wallet tx send ./key.key password network from to amount(Satoshi)",
		Long:  "Send bitcoins, example: ./wallet tx send ./key.key password network from to amount(Satoshi)",
		RunE:  c.runSendCmd,
	}
}

// runSendCmd 执行发送交易命令
func (c *WalletCommand) runSendCmd(cmd *cobra.Command, args []string) error {
	fmt.Println("send btc")
	var wif *btcutil.WIF
	var err error

	// 验证from地址是否存在于钱包中
	store := storage.NewLocalStorage(args[0])
	keys, err := store.ListKeys()
	if err != nil {
		return errors.Wrap(err, "list keys failed")
	}
	for _, key := range keys {
		// 解密私钥
		decryptedKey, err := utils.BIP38Decrypt(key, args[1], args[2])
		if err != nil {
			return errors.Wrap(err, "decrypt key failed")
		}
		wif, err = btcutil.DecodeWIF(string(decryptedKey))
		if err != nil {
			return errors.Wrap(err, "decode wif failed")
		}
		addr, err := address.NewBTCAddressFromWIF(wif).GenBech32Address(utils.GetNetwork(args[2]))
		if err != nil {
			return errors.Wrap(err, "generate bech32 address failed")
		}
		if addr == args[3] {
			break
		}
	}
	if wif == nil {
		return errors.New("from address not found")
	}

    
	amount, err := strconv.ParseInt(args[5], 10, 64)
	if err != nil {
		return errors.Wrap(err, "parse account failed")
	}
	// 构建交易输出
	txOut, _, err := buildTxOut(args[4], args[2],amount)
	if err != nil {
		return errors.Wrap(err, "build tx out failed")
	}

	// 构建交易输入
	msgTx,err := buildTxIn(wif, amount, txOut, args[2])
	if err != nil {
		return errors.Wrap(err, "build tx in failed")
	}

	// 发送交易
	txHash,err := client.SendRawTransaction(msgTx,false)
	if err != nil {
		return errors.Wrap(err, "send raw transaction failed")
	}

	fmt.Println("txHash:",txHash)

	return nil
}