項目中要實現一個功能，功能具體為，選擇不同的郵件名稱，產生不同的郵件模板。
功能圖例
實現思路上，想到了通過簡單工廠模式，簡單工廠模式只關心產出的產品不關心實現過程，只需要傳入一個類型嗎，就能得到想要的結果，十分符合開閉原則。
下面是該功能的UML類圖
首先，定義一個抽象的父類 IShMessageEmailService
然后定義實現類 ShMessageEmailEtaService 及 ShMessageEmailEtdService
最后定義工廠類 ShipMessageEmailFactory 工廠類接受一個類型碼參數，用來判定產生哪個產品。
代碼如下
public interface IShMessageEmailService {
public String getMessageText(ShDynamic dynamic, SailingSchedule sailingSchedule, String messageType);
}
@Service
public class ShMessageEmailEtaService extends BusinessService implements IShMessageEmailService {
@Autowired
private ShManifestCargoService shManifestCargoService;
@Autowired
private ShipPortService shipPortService;
@Override
public String getMessageText(ShDynamic dynamic, SailingSchedule sailingSchedule, String messageType) {
ShManifestCargo shManifestCargo = shManifestCargoService.findImpCargoAndBlNo(sailingSchedule.getId());
String loadPortCode = "";
String loadPortName = "";
String dischargePortCode = "";
String dischargePortName = "";
String loadPortCnName = "";
String dischargePortCnName = "";
String cargoDesc = "";
String blNo = "";
BigDecimal grossWeight = new BigDecimal(0);
if (shManifestCargo != null) {
if (shManifestCargo.getCargoDesc() != null) {
cargoDesc = shManifestCargo.getCargoDesc();
}
}
//裝貨港
if (shManifestCargo != null) {
blNo = shManifestCargo.getBlNo();
if (shManifestCargo.getGrossWeight() != null) {
grossWeight = shManifestCargo.getGrossWeight();
}
loadPortCode = shManifestCargo.getLoadPortCode();
dischargePortCode = shManifestCargo.getDischargePortCode();
if (loadPortCode != null) {
ShipPort shipPort = shipPortService.findByPortCode(loadPortCode);
loadPortName = shipPort.getName();
if (shipPort.getCountryCode() != null) {
loadPortCnName = shipPort.getCountryCode();
}
}
if (dischargePortCode != null) {
ShipPort shipPort = shipPortService.findByPortCode(dischargePortCode);
dischargePortName = shipPort.getName();
if (shipPort.getCountryCode() != null) {
dischargePortCnName = shipPort.getCountryCode();
}
}
}
StringBuilder sb = new StringBuilder();
sb.Append("Dear " + (sailingSchedule.getFirstClientName() == null ? "" : sailingSchedule.getFirstClientName()) + "n");
sb.append("n");
sb.append("Mt. Morning Calm " + sailingSchedule.getShipEnName() + "n");
sb.append("=== Cargo: " + cargoDesc + "=== n");
if ("".equals(loadPortCode) || "".equals(loadPortCnName)) {
sb.append("Port of Loading: " + loadPortName + loadPortCnName + "n");
} else {
sb.append("Port of Loading: " + loadPortName + "," + loadPortCnName + "n");
}
if ("".equals(dischargePortCode) || "".equals(dischargePortCnName)) {
sb.append("Port of Discharging: " + dischargePortName + dischargePortCnName + "n");
} else {
sb.append("Port of Discharging: " + dischargePortName + "," + dischargePortCnName + "n");
}
if ("".equals(blNo)) {
if (grossWeight.compareTo(new BigDecimal(0)) == 0) {
sb.append("B/L Quantity: n");
} else {
sb.append("B/L Quantity:" + grossWeight + "KGSn");
}
} else {
if (grossWeight.compareTo(new BigDecimal(0)) == 0) {
sb.append("B/L Quantity:" + blNo + "n");
} else {
sb.append("B/L Quantity:" + blNo + "," + grossWeight + "KGSn");
}
}
sb.append("n");
sb.append("--/-/- Arrived Guishan p/stnn");
sb.append("--/-/- Dropped anchor & NOR tenderedn");
sb.append("--/-/- POBn");
// 靠泊時間
sb.append("--/-/- First line ashoredn");
// ALL FAST
sb.append("--/-/- All line fasted at wharf No.4n");
// 開始聯檢時間
sb.append("--/-/- Free pratique grantedn");
// 開工時間
sb.append("--/-/- Estimated time of discharging commencen");
// 預計完工時間
sb.append("--/-/- Estimated time of discharging completen");
// 預計離泊時間
sb.append("--/-/- ETD (Subject to discharging & Main Channel traffic control) n");
sb.append("n");
sb.append("Arrival conditions:n");
// 抵港油水FO DO FW
BigDecimal arrvFo = dynamic.getArrvFo();
BigDecimal arrvDo = dynamic.getArrvDo();
BigDecimal arrvFw = dynamic.getArrvFw();
sb.append("Bunker - FO:" + (arrvFo == null ? "" : arrvFo) + "MTS/DO:" + (arrvDo == null ? "" : arrvDo) + "MTS/FW:" + (arrvFw == null ? "" : arrvFw) + "MTS n");
// 抵港吃水F A
BigDecimal arrvDraughtf = dynamic.getArrvDraughtf();
BigDecimal arrvDraughta = dynamic.getArrvDraughta();
sb.append("Draft - F:" + (arrvDraughtf == null ? "" : arrvDraughtf) + "M/A:" + (arrvDraughta == null ? "" : arrvDraughta) + "M n");
sb.append("n");
sb.append("Remark:n");
sb.append("1.Vessel can (un)berth at Xiaohu terminal only in daytime.n");
sb.append("2.Vessel can (un)berth only against ebb tide.n");
sb.append("3.Two tugboats assist berthing. n");
sb.append("n");
sb.append("Thank you for your kind agency appointment.If any inquries pls be free let me know. n");
sb.append("We respectfully remind you to also email the relevant information to the operator in charge of this voyage and do not reply this system email. n");
return sb.toString();
}
}
@Service
public class ShMessageEmailEtdService extends BusinessService implements IShMessageEmailService {
@Autowired
private ShManifestCargoService shManifestCargoService;
@Autowired
private ShipPortService shipPortService;
@Override
public String getMessageText(ShDynamic dynamic, SailingSchedule sailingSchedule, String messageType) {
ShManifestCargo shManifestCargo = shManifestCargoService.findExpCargoAndBlNo(sailingSchedule.getId());
String loadPortCode = "";
String loadPortName = "";
String dischargePortCode = "";
String dischargePortName = "";
String loadPortCnName = "";
String dischargePortCnName = "";
String cargoDesc = "";
String blNo = "";
BigDecimal grossWeight = new BigDecimal(0);
if(shManifestCargo!=null){
if(shManifestCargo.getCargoDesc()!=null){
cargoDesc = shManifestCargo.getCargoDesc();
}
}
//裝貨港
if (shManifestCargo!=null) {
blNo = shManifestCargo.getBlNo();
if(shManifestCargo.getGrossWeight()!=null){
grossWeight = shManifestCargo.getGrossWeight();
}
loadPortCode = shManifestCargo.getLoadPortCode();
dischargePortCode = shManifestCargo.getDischargePortCode();
if (loadPortCode != null) {
ShipPort shipPort = shipPortService.findByPortCode(loadPortCode);
loadPortName = shipPort.getName();
if(shipPort.getCountryCode()!=null){
loadPortCnName = shipPort.getCountryCode();
}
}
if (dischargePortCode != null) {
ShipPort shipPort = shipPortService.findByPortCode(dischargePortCode);
dischargePortName = shipPort.getName();
if(shipPort.getCountryCode()!=null){
dischargePortCnName = shipPort.getCountryCode();
}
}
}
StringBuilder sb = new StringBuilder();
sb.append("Dear " + (sailingSchedule.getFirstClientName() == null ? "" : sailingSchedule.getFirstClientName()) + "n");
sb.append("n");
sb.append("Mt. Morning Calm " + sailingSchedule.getShipEnName() + "n");
sb.append("=== Cargo: " + cargoDesc + "=== n");
if ("".equals(loadPortCode) || "".equals(loadPortCnName)) {
sb.append("Port of Loading: " + loadPortName + loadPortCnName + "n");
} else {
sb.append("Port of Loading: " + loadPortName + "," + loadPortCnName + "n");
}
if ("".equals(dischargePortCode) || "".equals(dischargePortCnName)) {
sb.append("Port of Discharging: " + dischargePortName + dischargePortCnName + "n");
} else {
sb.append("Port of Discharging: " + dischargePortName + "," + dischargePortCnName + "n");
}
// sb.append("Pls B Advd Abv Vsl's Arriving Conditon Asfs:n");
if ("".equals(blNo)) {
if(grossWeight.compareTo(new BigDecimal(0))==0) {
sb.append("B/L Quantity: n");
}else{
sb.append("B/L Quantity:"+ grossWeight + "KGSn");
}
}else{
if(grossWeight.compareTo(new BigDecimal(0))==0) {
sb.append("B/L Quantity:" + blNo + "n");
}else{
sb.append("B/L Quantity:" + blNo + "," + grossWeight + "KGSn");
}
}
sb.append("n");
sb.append("--/-/- Arrived Guishan p/stnn");
sb.append("--/-/- Dropped anchor & NOR tenderedn");
sb.append("--/-/- POBn");
// 靠泊時間
sb.append("--/-/- First line ashoredn");
// ALL FAST
sb.append("--/-/- All line fastedn");
// 開始聯檢時間
sb.append("--/-/- Free pratique grantedn");
// 開工時間
sb.append("--/-/- Hose onn");
// 預計完工時間
sb.append("--/-/- Discharging commencedn");
// 預計離泊時間
sb.append("--/-/- Discharging completed n");
sb.append("--/-/- Vapour pushing completed n");
sb.append("--/-/- Hose off n");
sb.append("--/-/- Outbound pilot on board n");
sb.append("--/-/- Sailed from Nansha n");
sb.append("--/-/- ETA Tokuyama n");
sb.append("n");
sb.append("Arrival conditions:n");
// 抵港油水FO DO FW
BigDecimal arrvFo = dynamic.getArrvFo();
BigDecimal arrvDo = dynamic.getArrvDo();
BigDecimal arrvFw = dynamic.getArrvFw();
sb.append("Bunker - FO:" + (arrvFo == null ? "" : arrvFo) + "MTS/DO:" + (arrvDo == null ? "" : arrvDo) + "MTS/FW:" + (arrvFw == null ? "" : arrvFw) + "MTSn");
// 抵港吃水F A
BigDecimal arrvDraughtf = dynamic.getArrvDraughtf();
BigDecimal arrvDraughta = dynamic.getArrvDraughta();
sb.append("Draft - F:" + (arrvDraughtf == null ? "" : arrvDraughtf) + "M/A:" + (arrvDraughta == null ? "" : arrvDraughta) + "Mn");
sb.append("n");
sb.append("Departure conditions:n");
// 離港油水FO DO FW
BigDecimal deptFo = dynamic.getDeptFo();
BigDecimal deptDo = dynamic.getDeptDo();
BigDecimal deptFw = dynamic.getDeptFw();
sb.append("Bunker - FO:" + (deptFo == null ? "" : deptFo) + "MTS/DO:" + (deptDo == null ? "" : deptDo) + "MTS/FW:" + (deptFw == null ? "" : deptFw) + "MTS n");
// 離港吃水F A
BigDecimal deptDraughtf = dynamic.getDeptDraughtf();
BigDecimal deptDraughta = dynamic.getDeptDraughta();
sb.append("Draft - F:" + (deptDraughtf == null ? "" : deptDraughtf) + "M/A:" + (deptDraughta == null ? "" : deptDraughta) + "M n");
sb.append("n");
sb.append("Remark:n");
sb.append("1.Vessel can (un)berth at Xiaohu terminal only in daytime.n");
sb.append("2.Vessel can (un)berth only against ebb tide.n");
sb.append("3.Two tugboats assist berthing. n");
sb.append("4.One tugboat assist unberthing. n");
sb.append("n");
sb.append("Thanks again for your kind agency appointment.If any inquries pls be free let me know.n");
sb.append("We respectfully remind you to also email the relevant information to the operator in charge of this voyage and do not reply this system email. n");
return sb.toString();
}
}
@Service
public class ShipMessageEmailFactory {
public static final String ETA_MESSAGE = "etaMessage";
public static final String ETD_MESSAGE = "etdMessage";
public static final String PROGRESS_MESSAGE = "progressMessage";
@Autowired
private ShMessageEmailEtaService shMessageEmailEtaService;
@Autowired
private ShMessageEmailEtdService shMessageEmailEtdService;
public IShMessageEmailService createProduct(String messageType) {
if (messageType.equals(ETA_MESSAGE)) {
return shMessageEmailEtaService;
} else if (messageType.equals(ETD_MESSAGE)) {
return shMessageEmailEtdService;
}
return null;
}
}
//調用該方法
@RequestMapping(value = "query_email_model", method = {RequestMethod.GET})
public SailingQueryEntity queryEmailModel(@RequestParam("id") String id, @RequestParam("messageType") String messageType) {
SailingQueryEntity entity = new SailingQueryEntity();
SailingSchedule sailingSchedule = service.find(SailingSchedule.class, id);
List<ShDynamic> dynamic = shipDynamicService.findBySailingScheduleId(id);
ShDynamic dynamicEntity = dynamic.get(0);
String text = "";
if(!messageType.equals(shipMessageEmailFactory.PROGRESS_MESSAGE)){
IShMessageEmailService shMessageEmailService = shipMessageEmailFactory.createProduct(messageType);
text = shMessageEmailService.getMessageText(dynamicEntity, sailingSchedule, messageType);
}
entity.setArrivedText(text);
return entity;
}
需要注意的是，一般簡單工廠模式的工廠類都是使用static進行修飾，即靜態方法。但是我在使用static進行修飾時，卻報錯，原因是，通過spring管理的service不是靜態的，而靜態方法，要求返回值必須是靜態的才行，將static去掉可以了。簡單工廠模式很簡單，不屬于23中設計模式，但是對于軟件的拓展性，確是十分重要。
