一、流程如下：

1、买家下单

2、卖家接单

3、买家付押金

4、卖家付押金

5、卖家发出货物

6、运输方甲收到货物

7、运输方甲送到货物

8、运输方乙收到货物

9、运输方乙送到货物

10、买家收到货物

二、将以上规则写入编译合约sol文件

/*This is a simple showcase smart contract example for trade finance / supply chain interactions.It could be improved in several ways:- add timeouts for state reversal (e.g. object is released by one party but not accepted by next)= add escrow payments also for carriers, otherwise they can block forever- add delivery dates for carriers, if not met their escrow balance will be punished- add insurance interface for, e.g. transport delay or damage insurance*/contract TradeHandler {    address public seller;    address public carrier1;    address public carrier2;    address public buyer;    uint public purchasePrice;    uint public carrier1Fee;    uint public carrier2Fee;        enum WaitingFor {         BuyerEscrowPayment,        SellerEscrowPayment,        SellerRelease,        Carrier1Accept,        Carrier1Release,        Carrier2Accept,        Carrier2Release,        BuyerAccept,        Completed    }        WaitingFor state;    // constructor sets all actors and fees    function TradeHandler(        address _seller,        address _carrier1,        address _carrier2,        uint _carrier1Fee,        uint _carrier2Fee,        uint _purchasePrice)    {        buyer = msg.sender;        seller = _seller;        carrier1 = _carrier1;        carrier2 = _carrier2;        carrier1Fee = _carrier1Fee;        carrier2Fee = _carrier2Fee;        purchasePrice = _purchasePrice;    }        function reset(        address _seller,        address _carrier1,        address _carrier2,        uint _carrier1Fee,        uint _carrier2Fee,        uint _purchasePrice)    {        // only allow recylcing of contract if previous trade is completed        if (state != WaitingFor.Completed)            throw;        buyer = msg.sender;        seller = _seller;        carrier1 = _carrier1;        carrier2 = _carrier2;        carrier1Fee = _carrier1Fee;        carrier2Fee = _carrier2Fee;        purchasePrice = _purchasePrice;    }    function () payable {        // todo: one could check for timeouts and revert transitions if required        // once trade is completed, do not allow further interaction        if (state == WaitingFor.Completed)            throw;        // each actor is only responsible for their respective state transfer, reject all others        if (msg.sender == buyer && state != WaitingFor.BuyerEscrowPayment && state != WaitingFor.BuyerAccept)            throw;        if (msg.sender == seller && state != WaitingFor.SellerEscrowPayment && state != WaitingFor.SellerRelease)            throw;        if (msg.sender == carrier1 && state != WaitingFor.Carrier1Accept && state != WaitingFor.Carrier1Release)            throw;        if (msg.sender == carrier2 && state != WaitingFor.Carrier2Accept && state != WaitingFor.Carrier2Release)            throw;        // make sure that the right amounts are being paid into this escrow contract by buyer and seller        if (state == WaitingFor.BuyerEscrowPayment && msg.value != 2 * purchasePrice + carrier1Fee + carrier2Fee)            throw;        if (state == WaitingFor.SellerEscrowPayment && msg.value != purchasePrice)            throw;                // perform state transitions        if (state == WaitingFor.BuyerEscrowPayment)            state = WaitingFor.SellerEscrowPayment;        else if (state == WaitingFor.SellerEscrowPayment)            state = WaitingFor.SellerRelease;        else if (state == WaitingFor.SellerRelease)            state = WaitingFor.Carrier1Accept;        else if (state == WaitingFor.Carrier1Accept)            state = WaitingFor.Carrier1Release;        else if (state == WaitingFor.Carrier1Release)            state = WaitingFor.Carrier2Accept;        else if (state == WaitingFor.Carrier2Accept) {            state = WaitingFor.Carrier2Release;            carrier1.send(carrier1Fee);        } else if (state == WaitingFor.Carrier2Release)            state = WaitingFor.BuyerAccept;        else if (state == WaitingFor.BuyerAccept) {            state = WaitingFor.Completed;            carrier2.send(carrier2Fee);            seller.send(2 * purchasePrice);            buyer.send(purchasePrice);        }    }} 　　注：以上需要转换成新版的sol文件

三、操作：

 如下图所示：

参考：https://github.com/validitylabs/TradeManager