wrrmsample.java

j2me实例代码

package rms;

import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;
import javax.microedition.rms.*;
import javax.microedition.lcdui.*;
import java.io.*;

public class WRRMSample extends MIDlet implements CommandListener{
	private Display display;
	private Alert alert;
	private Form form;
	private Command exit;
	private Command start;
	private RecordStore recordstore=null;
	private RecordEnumeration re;
	public WRRMSample() {
		super();
		display=Display.getDisplay(this);
		exit=new Command("Exit",Command.SCREEN,1);
		start=new Command("Start",Command.SCREEN,1);
		form=new Form("Record Store");
		form.addCommand(exit);
		form.addCommand(start);
		form.setCommandListener(this);
		
	}

	protected void startApp() throws MIDletStateChangeException {
		display.setCurrent(form);

	}

	protected void pauseApp() {
		

	}

	protected void destroyApp(boolean arg0){
		

	}

	public void commandAction(Command c, Displayable d) {
		if(c==exit){
			destroyApp(false);
			notifyDestroyed();
		}
		else if(c==start){
			try{
				recordstore=RecordStore.openRecordStore("myRecordStore",true);
			}catch(Exception e){
				alert=new Alert("Creating fail",e.toString(),null,AlertType.WARNING);
				alert.setTimeout(Alert.FOREVER);
				display.setCurrent(alert);
			}
			
			try{
				byte[] outputRecord;
				String[] outputString={"First","Second","Third"};
				boolean outputBoolean[]={true,true,false};
				int outputInteger[]={10,15,20};
				ByteArrayOutputStream os=new ByteArrayOutputStream();
				DataOutputStream daos=new DataOutputStream(os);
				for(int i=0;i<3;i++){
					daos.writeUTF(outputString[i]);
					daos.writeBoolean(outputBoolean[i]);
					daos.writeInt(outputInteger[i]);
					daos.flush();
					outputRecord=os.toByteArray();
					recordstore.addRecord(outputRecord,0,outputRecord.length);
				}
				os.reset();
				os.close();
				daos.close();
			}catch(Exception e){
				alert=new Alert("Writing fail",e.toString(),null,AlertType.WARNING);
				alert.setTimeout(Alert.FOREVER);
				display.setCurrent(alert);
			}
			
			try{
				StringBuffer buffer=new StringBuffer();
				byte[] byteInputData=new byte[300];
				
				ByteArrayInputStream is=new ByteArrayInputStream(byteInputData);
				DataInputStream dis=new DataInputStream(is);
				
				re=recordstore.enumerateRecords(null,null,false);
				while(re.hasNextElement()){
					recordstore.getRecord(re.nextRecordId(),byteInputData,0);
					buffer.append(dis.readUTF());
					buffer.append("\n");
					buffer.append(dis.readBoolean());
					buffer.append("\n");
					buffer.append(dis.readInt());
					buffer.append("\n");
					
				}
				alert=new Alert("Reading",buffer.toString(),null,AlertType.CONFIRMATION);
				alert.setTimeout(Alert.FOREVER);
				display.setCurrent(alert);
				
				is.close();
				dis.close();
				
			}catch(Exception e){
				alert=new Alert("Reading fail",e.toString(),null,AlertType.WARNING);
				alert.setTimeout(Alert.FOREVER);
				display.setCurrent(alert);
			}
			try{
				recordstore.closeRecordStore();
			}catch(Exception e){
				alert=new Alert("Closing fail",e.toString(),null,AlertType.WARNING);
				alert.setTimeout(Alert.FOREVER);
				display.setCurrent(alert);
				
			}	
			if(RecordStore.listRecordStores()!=null){
				try{
					RecordStore.deleteRecordStore("myRecordStore");
				}catch(Exception e){
					alert=new Alert("Removing fail",e.toString(),null,AlertType.WARNING);
					alert.setTimeout(Alert.FOREVER);
					display.setCurrent(alert);
				}
			}			
		}
	}
}