multifieldsmidlet.java

透过Java编程设计的网站。包含很多功能点

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.rms.*;
import java.io.*;
public class MultiFieldsMIDlet extends MIDlet 
implements CommandListener {
  private Command exitCommand;
  private Display display;
  private String[] names ={"黄聪明","黄镇樟","郑雅文"};

  public MultiFieldsMIDlet() {
    display = Display.getDisplay(this);
    exitCommand = new Command("离开", Command.EXIT, 1);
  }

  public void startApp() {
	TextBox aTextBox = new TextBox("主画面",null,256,TextField.ANY);

	RecordStore rs = null;
	byte[] nameEmail=null;
	boolean existingOrNot = false;
	boolean OK = true;

	existingOrNot = existing("aRS3");
	if(existingOrNot){
	   try{
		rs = RecordStore.openRecordStore("aRS3",false);
            }
            catch(Exception e){
		OK = false;
	   }
	   finally{
		 if(OK){
			 aTextBox.setString("aRS3已存在并且已打开");
	          }
	          else{
			aTextBox.setString("aRS3已存在但无法打开");
	          }
            }
        }
        else{
	try{
		rs = RecordStore.openRecordStore("aRS3",true);
	    }
             catch(Exception e){
		OK = false;
	    }
	    finally{
		if(OK){
	    	aTextBox.setString("aRS3虽未存在，但已创建并完成打开的操作！");
		}
		else{
	    	aTextBox.setString("aRS3虽未存在，但无法创建，打开文件失败！");
		}
	}
	}

    Person2 aPerson = null;
    if(OK)
       try{
		   for(int i=0;i<names.length;i++){
			  aPerson = new Person2();
	    	  aPerson.write(names[i],"[e-mail]",36);
	    	  byte[] data = aPerson.changeToByteArray();
	    	  int recordID = aPerson.getRecordID();
	    	  if(recordID != -1){
	    	    rs.setRecord(recordID,data,0,data.length);
			  }
	    	  else{
			recordID = rs.addRecord(data,0,data.length);
			aPerson.setRecordID(recordID);
		  }
		  	  aPerson = null;
		    }
			aTextBox.setString("已完成新增记录的操作！");
		  }
	   catch(Exception e){
			aTextBox.setString("新增记录的操作失败！");
	   }

    String result="";
    aPerson = new Person2();

    if(OK)
       try{
	  int number = rs.getNumRecords();
	  byte[] data;

           for(int i =1;i< rs.getNextRecordID();i++){
	data = rs.getRecord(i);
               aPerson.changeFromByteArray(data);
               result += "第" + i + "笔\n" +
                         "姓名：" + aPerson.getName() + "\n" +
		"E-mail：" + aPerson.getEMail() + "\n" +
	                "年龄：" + aPerson.getAge() + "\n";
            }

	        result += "共有" + number + "笔记录：\n";
	    	aTextBox.setString(result);
		  }
	   catch(Exception e){
		   aTextBox.setString("获取记录的操作失败！"  );
		   try{
				rs.closeRecordStore();
				System.out.println("1.Closed.");
		        RecordStore.deleteRecordStore("aRS3");
				System.out.println("delete OK");
			}
			catch(Exception x){
            }
	   }
    finally{
	   try{
		   if(rs != null) rs.closeRecordStore();
		   rs.deleteRecordStore("aRS3");
	   }
	   catch(Exception e){
	   }
	}

    aTextBox.setString(result);
    aTextBox.addCommand(exitCommand);
    aTextBox.setCommandListener(this);
    display.setCurrent(aTextBox);
  }

  public void pauseApp() {
  }
  public void destroyApp(boolean unconditional) {
  }

  public boolean existing(String recordStoreName) {
    boolean existingOrNot = false;
    RecordStore rs = null;
    if(recordStoreName.length() > 32) return false;
    try{
	    rs = RecordStore.openRecordStore(recordStoreName,false);
    }
    catch(RecordStoreNotFoundException e){
	    existingOrNot = false;
    }
    catch(Exception e){
    }
    finally{
    	try{
	        rs.closeRecordStore();
	    }
	    catch(Exception e){
	    }
    }
   return existingOrNot;
  }

  public void commandAction(Command c, Displayable s) {
     destroyApp(false);
     notifyDestroyed();
  }
}

class Person2{
	private int ID = -1;
	private String name;
	private String EMail;
	private int age;

	public void write(String name, String EMail, int age){
		this.name = name;
		this.EMail = EMail;
		this.age = age;
	}
	public void setRecordID(int ID){
		this.ID = ID;
	}
	public int getRecordID(){
		return ID;
	}
	public byte[] changeToByteArray(){
		byte[] data = null;

		try{
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
 	        DataOutputStream dos = new DataOutputStream(baos);
		dos.writeUTF(name);
		dos.writeUTF(EMail);
	        dos.writeInt(age);
		data = baos.toByteArray();

		baos.close();
		dos.close();
		}
		catch(Exception e){
		}
		return data;
	}

	public void changeFromByteArray(byte[] data){
		try{
		ByteArrayInputStream bais = new ByteArrayInputStream(data);
		DataInputStream dis = new DataInputStream(bais);

			name = dis.readUTF();
			EMail = dis.readUTF();
			age = dis.readInt();

			bais.close();
			dis.close();
		}
		catch(Exception e){
		}
	}
	public String getName(){
		return name;
	}
	public String getEMail(){
		return EMail;
	}
	public int getAge(){
		return age;
	}
}