我是 J2ME 的新手，我正在学习我们使用它的课程。我使用选择组文本字段等创建了一个简单的旅行预订 MIDlet。然后我添加了一个记录存储来捕获此信息。我现在有一个只需要用户名的用户登录，但我不知道如何验证用户名是否在记录存储中，所以只要用户名的文本字段不为空，我就接受任何一个. 我的第一个问题是如何验证用户是否存在，我已经可以创建一个帐户。第二个问题是如何不按 id 搜索记录存储，而是说为记录存储的每一行使用一定范围内的字符串。
到目前为止，这是我的代码：
$import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.util.Date;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.MIDlet;
import javax.microedition.rms.*;
/**
* @author XayBlu
*/
public class tripMe extends MIDlet implements CommandListener {
Form startForm, airForm, trainForm, cruiseForm, autoForm, Ext, Pass,home,login, create;
Command Exit, Trip, Cinfo, AutC,AiC,CrC, info,Tme,trainC, logC,signC, createC, prev, newTrip, Home;
ChoiceGroup trans,hCAP, passCNT,airT,airC,AuC,AuT,CrL,CcabT,Tseat,TOP;
Display Xdisplay;
TextField Eneed, uName, uName2;
Alert Final, FinalT, Sucess, nope;
DateField dDate, rDate;
Date d,r;
Image [] image;
String details =" ",tt="", Trav, Rdate, Ddate, extraA, Pcount,specialA, TT,AIR2, AIR,AUTO,AUTO2,CRUISE,CRUISE2,TRAIN,TRAIN2, USERS="USERS";
String op[] = {"Air","Auto","Cruise","Train"}; //Array Items for Choice Groups
String ep[] = {"Wheel Chair","Baby Seat","Extended Seatbelt","Extra Pillows","Oxygen Tank","GPS"};
String count[] = {"1","2","3","4","5","6","7","8"};
String AL []= {"American Airlines","Delta","US Airways","South West Airlines","United Airlines"};
String Rental [] = {"Alamo","Avis","Budget","Enteprise","Dollar","Hertz"};
String CL [] = {"Carnival","Norwegian","Royal Caribbean","Celebrity X","MSC"};
String CT [] = {"Compact","Standard","Full","SUV","Luxury","Sports"};
String Cabin [] = {"Suite","Ocean Balcony","Standard","Economy"};
String tCAB[] = {"Standard Seat","Sleeper Cart"};
String Toptions[] ={"Extra Luggage room","Salad Buffet","Wifi Access","Extra Blanket"};
RecordStore usr,itt;
RecordEnumeration recEnum = null;
RecordFilter filter = null;
int Umax=5;
int tran1 =6;
String last;
Byte [] data = new Byte[Umax];
/* NEW COMMANDS FOR FLEXIBLE USER INPUT TO RECORD STORES */
public void writeRecord(String str){ // User to insert user input to record stores
byte[] rec = str.getBytes();
try{
usr.addRecord(rec, 0, rec.length);
}catch (Exception e){}
}
public void writeInfo(String str){ // User to insert user input to record stores
byte[] rec = str.getBytes();
try{
usr.addRecord(rec, tran1, rec.length);
}catch (Exception e){}
}
public void updateRecord(String str){
try{
usr.setRecord(1, str.getBytes(), 0, str.length());
}catch (Exception e){}
}
public void deleteRecord(){
try{
usr.deleteRecord(1);
}catch (Exception e){}
}
public void closeRecord(){
try{
usr.closeRecordStore();
}catch (Exception e){}
}
public void deleteRecStore(){
if (RecordStore.listRecordStores() != null){
try{
RecordStore.deleteRecordStore(USERS);
}catch (Exception e){}
}
}
public void openRecStore()
{
try
{
// The second parameter indicates that the record store
// should be created if it does not exist
usr = RecordStore.openRecordStore(USERS, true );
}
catch (Exception e)
{
System.out.print("Could not open record store");
}
}
public void readRecords()
{
try
{
// Intentionally make this too small to test code below
byte[] recData = new byte[5];
int len;
for (int i = 1; i <= usr.getNumRecords(); i++)
{
if (usr.getRecordSize(i) > recData.length)
recData = new byte[usr.getRecordSize(i)];
len = usr.getRecord(i, recData, 0);
home.append(new String(recData,0,len));
// System.out.println("Record #" + i + ": " + new String(recData, 0, len));
// System.out.println("------------------------------");
}
}
catch (Exception e)
{
nope = new Alert("Sorry no match!",null,null,AlertType.INFO);
nope.setTimeout(Alert.FOREVER); //Append string for FinalT Alert
Xdisplay.setCurrent(nope, login);
}
}
}
class Filter implements RecordFilter {
private String search = null;
private ByteArrayInputStream inputstream = null;
private DataInputStream datainputstream = null;
public Filter(String search) {
this.search = search.toLowerCase();
}
public void filterClose() {
try {
if (inputstream != null) {
inputstream.close();
}
if (datainputstream != null) {
datainputstream.close();
}
} catch (Exception error) {
}
}
}
public tripMe (){
try{ //Initializing individual images for Choice Group Icons
Image car = Image.createImage("/car2.png");
Image plane = Image.createImage("/plane2.png");
Image train = Image.createImage("/train2.png");
Image cruise = Image.createImage("/cruise2.png");
image = new Image[] {plane,car,cruise,train}; //Initializing Image array for ChoiceGroup
}
catch (java.io.IOException err) {System.out.print("Could not load pics"); } //Throws exception if pic cannot be found
startForm = new Form("Get Away Today"); //Initialization of forms
Pass = new Form ("Passenger Information");
airForm = new Form("Low Prices!");
autoForm = new Form("Find the best car for you");
Ext = new Form("Itinerary Details");
Ext.setTicker(new Ticker("Enjoy Your Vacation"));
cruiseForm = new Form("Sail Away Today");
trainForm = new Form("Chuuu- Chuuu");
login = new Form("Sign up Today");
home = new Form("Welcome Back");
create = new Form("Create an account");
trans = new ChoiceGroup("Select travel type",ChoiceGroup.EXCLUSIVE,op,image); //Transport tation choice group initialized with corresponding string and image array
Exit = new Command("Exit", Command.EXIT,1);//Adding necessary commands
Trip = new Command("Go", Command.SCREEN,2);//Adding go command which allows you to select travel type
signC = new Command("Sign up",Command.SCREEN,2);
logC = new Command("Log in",Command.SCREEN,2);
createC = new Command("OK",Command.SCREEN,2);
prev = new Command("History",Command.SCREEN,2);
newTrip = new Command("Reservations",Command.SCREEN,2);
Home = new Command("Log out",Command.SCREEN,1);
hCAP = new ChoiceGroup("Extra Assistance", ChoiceGroup.MULTIPLE,ep,null);//Passenger Info items
passCNT = new ChoiceGroup("Number of Passengers:",ChoiceGroup.POPUP,count,null);
rDate = new DateField("Return Date",DateField.DATE_TIME);//Could not get the DateField to return string date value
dDate = new DateField("Departure Date",DateField.DATE_TIME);
Eneed = new TextField("Special Needs","",50,TextField.ANY);
uName = new TextField("User Name","",5,TextField.ANY);
uName2 = new TextField("User Name","",5,TextField.ANY);
info = new Command("Next",Command.SCREEN,2);
AiC = new Command("Complete",Command.SCREEN,2);//Air travel option items
airT = new ChoiceGroup("Choose Airline", ChoiceGroup.POPUP,AL,null);//Airline selection
airC = new ChoiceGroup("Select Class",ChoiceGroup.EXCLUSIVE);//Economy or first cass?
airC.append("First Class", null);//Adding elements to Choice Group
airC.append("Economy", null);
AuC = new ChoiceGroup("Choose rental company", ChoiceGroup.POPUP,Rental,null);//Auto travel option items
AuT = new ChoiceGroup("Select Vehicle Type", ChoiceGroup.EXCLUSIVE, CT,null);//Choicegroup for Vehicle type
AutC = new Command("Drive away", Command.SCREEN,2);//Adding drive away command to form
CrL = new ChoiceGroup("Select Cruise Line Comp.", ChoiceGroup.POPUP,CL,null);//Cruise option Items, Cruise line choicegroup
CcabT = new ChoiceGroup("Select Cabin Type", ChoiceGroup.EXCLUSIVE,Cabin,null);//Cabin type choice group
CrC = new Command("Cruise", Command.SCREEN,2);//Cruise form command being added
trainC = new Command("Track!", Command.SCREEN,2);//Train option items, Train form command
Tseat = new ChoiceGroup("Seat Type", ChoiceGroup.EXCLUSIVE,tCAB,null);//Choicegroup for train seat type
TOP = new ChoiceGroup("Extra Options", ChoiceGroup.POPUP,Toptions,null);//Train extra options choice group
/* Appending Items to necessary Forms*/
create.append(uName2);
create.addCommand(createC);
create.setCommandListener(this);
home.addCommand(prev);
home.addCommand(newTrip);
home.setCommandListener(this);
login.append(uName);
login.addCommand(logC);
login.addCommand(signC);
login.setCommandListener(this);
startForm.append(trans);
startForm.addCommand(Exit);
startForm.addCommand(Trip);
startForm.setCommandListener(this);
Pass.append(dDate);
Pass.append(rDate);
Pass.append(hCAP);
Pass.append(passCNT);
Pass.append(Eneed);
Pass.addCommand(info);
Pass.setCommandListener(this);
airForm.append(airT);
airForm.append(airC);
airForm.addCommand(AiC);
airForm.setCommandListener(this);
autoForm.addCommand(AutC);
autoForm.append(AuC);
autoForm.append(AuT);
autoForm.setCommandListener(this);
cruiseForm.addCommand(CrC);
cruiseForm.append(CrL);
cruiseForm.append(CcabT);
cruiseForm.setCommandListener(this);
trainForm.addCommand(trainC);
trainForm.append(Tseat);
trainForm.append(TOP);
trainForm.setCommandListener(this);
Ext.addCommand(Exit);
Ext.addCommand(Home);
Ext.setCommandListener(this);
}
public void startApp() {
Xdisplay= Display.getDisplay(this);
Xdisplay.setCurrent(login);
}
public void pauseApp() {
}
public void destroyApp(boolean unconditional) {
notifyDestroyed();
}
public void commandAction(Command c, Displayable displayable){
try {
usr = RecordStore.openRecordStore(USERS, false);
} catch (Exception e) {
Sucess = new Alert("Error","Could not open Record Strore",null,AlertType.INFO);
Sucess.setTimeout(Alert.FOREVER); //Append string for FinalT Alert
Xdisplay.setCurrent(Sucess, login);
}
if(c==signC)
{
Xdisplay.setCurrent(create);
}
else if(c == newTrip)
{
Xdisplay.setCurrent(startForm);
}
else if(c == prev)
{
try {
String record = "";
for (int i = 1; i < usr.getNextRecordID(); i++) {
record = new String(usr.getRecord(i));
}
home.append(record);
} catch (Exception e) {
home.append("Could not retrieve data");
try {
usr.closeRecordStore();
RecordStore.deleteRecordStore(USERS);
} catch (Exception x) {
}
}
try {
usr.closeRecordStore();
} catch (Exception e) {
}
}
else if(c==createC)
{
try {
usr = RecordStore.openRecordStore(USERS, true);
} catch (RecordStoreException ex) {
ex.printStackTrace();
}
if(!"".equals(uName2.getString()))
{
writeRecord(uName2.getString());
}
Sucess = new Alert("Welcome to the mile high club","Hello:"+uName2.getString(),null,AlertType.INFO);
Sucess.setTimeout(Alert.FOREVER); //Append string for FinalT Alert
Xdisplay.setCurrent(Sucess, login);
}
else if (c == logC)
{
if(!"".equals(uName.getString()))
{
String name = uName.getString();
byte[] data = name.getBytes();
Xdisplay.setCurrent(home);
}
else
{
Sucess = new Alert("Please enter user name!","Invalid user name",null,AlertType.INFO);
Sucess.setTimeout(Alert.FOREVER); //Append string for FinalT Alert
Xdisplay.setCurrent(Sucess, login);
}
}
else if(c==Trip)
{
tt +="Travel Mode: "+ trans.getString(trans.getSelectedIndex())+"\n";
if(trans.isSelected(0))
{
TT="A"; //Sets the type of travel based on choicegroup user selection
Xdisplay.setCurrent(Pass);
}
else if(trans.isSelected(1))
{
TT="B";
Xdisplay.setCurrent(Pass);
}
else if(trans.isSelected(2))
{
TT="C";
Xdisplay.setCurrent(Pass);
}
else if(trans.isSelected(3))
{
TT="D";
Xdisplay.setCurrent(Pass);
}
}
else if (c == info)
{
for(int i = 0; i < hCAP.size(); i++) //Checks to see what items are selected in a ChoiceGrou
{
if(hCAP.isSelected(i))
{
details += hCAP.getString(i)+","; //If item is selected then it is appended to the string details
}
}
Rdate = rDate.getDate().toString();
Ddate = dDate.getDate().toString();
tt+= "Departure Date: "+ Ddate.substring(0, 10)+"\n";
tt+= "Return Date: "+ Rdate.substring(0, 10)+"\n";
Pcount = passCNT.getString(passCNT.getSelectedIndex()); //Gets passenger count from choicegroup of integers
specialA = Eneed.getString();
Final = new Alert("Your travel details: \n","Requested Devices:"+details+"\nPassenger Count: "+Pcount+
"\nSpecific Request: "+specialA,null,AlertType.INFO); //Appends string for alert
Final.setTimeout(Alert.FOREVER);
if("A".equals(TT)){ //Directs user to form based on travel type choice
Xdisplay.setCurrent(Final,airForm);
}
else if("B".equals(TT)){//Directs user to form based on travel type choice
Xdisplay.setCurrent(Final, autoForm);
}
else if ("C".equals(TT)){//Directs user to form based on travel type choice
Xdisplay.setCurrent(Final, cruiseForm);
}
else if ("D".equals(TT)){//Directs user to form based on travel type choice
Xdisplay.setCurrent(Final, trainForm);
}
}
else if(c==AiC)
{
AIR = airT.getString(airT.getSelectedIndex());//Retrieves selected item from choicegroup
tt+="Company: "+AIR+"\n";
AIR2 = airC.getString(airC.getSelectedIndex());//Retrieves selected item from choicegroup
FinalT = new Alert("Flight Details: \n","Airline Company:"+AIR+"\nSeat Class: "+AIR2,null,AlertType.INFO);
FinalT.setTimeout(Alert.FOREVER); //Append string for FinalT Alert
Trav ="Customer Details \nRequested Devices:\n"+details+"\n# of Passengers:\n "+Pcount+"\nSpecific customer request:\n "+specialA+
"\nDeparture Date: "+Ddate+"\nReturn Date: "+Rdate;
Ext.append(Trav);
extraA ="Carrier Details\n"+"Airline Carrier: "+AIR+"\nSeat Type: "+AIR2; //Append string for final display of info to user
Ext.append(extraA);
try {
usr = RecordStore.openRecordStore(USERS, true);
} catch (RecordStoreException ex) {
}
writeRecord("\n"+tt);
Xdisplay.setCurrent(FinalT,Ext);
}
else if (c == AutC)
{
AUTO = AuC.getString(AuC.getSelectedIndex());//Retrieves selected item from choicegroup
tt += "Company: "+AUTO+"\n";
AUTO2 = AuT.getString(AuT.getSelectedIndex());//Retrieves selected item from choicegroup
FinalT = new Alert("Auto Details: \n","Car Rental Company:"+AUTO+"\nVehicle Class: "+AUTO2,null,AlertType.INFO);
FinalT.setTimeout(Alert.FOREVER);
Trav ="Customer Details \nRequested Devices:\n"+details+"\n# of Passengers:\n "+Pcount+"\nSpecific customer request:\n "+specialA+
"\nDeparture Date: "+Ddate+"\nReturn Date: "+Rdate;
Ext.append(Trav);
extraA ="Carrier Details\n"+"Rental Company: "+AUTO+"\nVehicle Class: "+AUTO2; //Append string for final display of info to user
Ext.append(extraA);
try {
usr = RecordStore.openRecordStore(USERS, true);
} catch (RecordStoreException ex) {
}
writeRecord("\n"+tt);
Xdisplay.setCurrent(FinalT, Ext);
}
else if (c == CrC)
{
CRUISE = CrL.getString(CrL.getSelectedIndex());
tt += "Company: "+CRUISE+"\n";
CRUISE2 = CcabT.getString(CcabT.getSelectedIndex());
FinalT = new Alert("Cruise Details: \n","Cruise Line Company:"+CRUISE+"\nCabin Type:"+CRUISE2,null,AlertType.INFO);
FinalT.setTimeout(Alert.FOREVER);
Trav ="Customer Details \nRequested Devices:\n"+details+"\n# of Passengers:\n "+Pcount+"\nSpecific customer request:\n "+specialA+
"\nDeparture Date: "+Ddate+"\nReturn Date: "+Rdate;
Ext.append(Trav);
extraA ="Carrier Details\n"+"Cruise Line Company: "+CRUISE+"\nCabin Type: "+CRUISE2; //Append string for final display of info to user
Ext.append(extraA);
try {
usr = RecordStore.openRecordStore(USERS, true);
} catch (RecordStoreException ex) {
}
writeRecord("\n"+tt);
Xdisplay.setCurrent(FinalT, Ext);
}
else if (c == trainC)
{
TRAIN = Tseat.getString(Tseat.getSelectedIndex());
TRAIN2 = TOP.getString(TOP.getSelectedIndex());
FinalT = new Alert("Train Details: \n","Train Seat Type:"+TRAIN+"\nExtra Amenities:"+TRAIN2,null,AlertType.INFO);
FinalT.setTimeout(Alert.FOREVER);
Trav ="Customer Details \nRequested Devices:\n"+details+"\n# of Passengers:\n "+Pcount+"\nSpecific customer request:\n "+specialA+
"\nDeparture Date: "+Ddate+"\nReturn Date: "+Rdate;
Ext.append(Trav);
extraA ="Carrier Details\n"+"Train Seat Type: "+TRAIN+"\nExtra Amenities: "+TRAIN2; //Append string for final display of info to user
Ext.append(extraA);
try {
usr = RecordStore.openRecordStore(USERS, true);
} catch (RecordStoreException ex) {
}
writeRecord("\n"+tt);
Xdisplay.setCurrent(FinalT, Ext);
}
else if(c == Home)
{
home.deleteAll();
Xdisplay.setCurrent(login);
}
else if(c==Exit)
{
destroyApp(false);
notifyDestroyed();
}
}
}