请教一个关于向j2me数据库内写入数据的问题
<P>我的程序已经写好，而且编译通过，但是在save的时候不能将数据保存到数据库中<BR>提示为：java.lang.NullPointerException<BR> at Fourth.doSave(+221)<BR> at Fourth.commandAction(+457) <BR> at javax.microediton.ledui.Display$DisplayAccessor.commandAction(+152)<BR> at com.sun.kvem.midp.lcdui.EnmlEventHandle$EventLoop.run(+459)<BR>下面是我关于保存的代码，希望好心的大侠相助，小妹感激不尽！谢谢<BR></P><P><BR>private void doSave(){<BR> RecordStore rs=null;<BR> byte[] nameEmail=null;<BR> boolean existingOrNot=false;<BR> <BR> existingOrNot=existing("aPerson");<BR> if(existingOrNot){<BR> try{<BR> rs=RecordStore.openRecordStore("aPerson",false);<BR> }<BR> catch(Exception e){<BR> }<BR> }<BR> else{<BR> try{<BR> rs=RecordStore.openRecordStore("aPerson",true);<BR> }<BR> catch(Exception e){<BR> }<BR> }<BR> <BR> Person aPerson=null;<BR> <BR> try{<BR> aPerson=new Person();<BR> <BR> aPerson.write(nameField.getString(),<BR> EMailField.getString(),<BR> Integer.parseInt(ageField.getString())<BR> );<BR> byte[] data=aPerson.changeToByteArray();<BR> int recordID=aPerson.getRecordID();<BR> if(modificationID!=0)<BR> recordID=modificationID;<BR> <BR> System.out.println("record ID: "+recordID);<BR> if(recordID!=-1){<BR> rs.setRecord(recordID,data,0,data.length);<BR> modificationID=0;<BR> }<BR> else{<BR> recordID=rs.addRecord(data,0,data.length);<BR> aPerson.setRecordID(recordID);<BR> }<BR> aPerson=null;<BR> nameField.setLabel("消息");<BR> nameField.setString("完成新增!"); <BR> }<BR> catch(Exception e){<BR> nameField.setLabel("注意");<BR> nameField.setString("失败!");<BR> }<BR> <BR> try{<BR> if(rs!=null)<BR> rs.closeRecordStore();<BR> //rs.deleteRecordStore("aPerson");<BR> }<BR> catch(Exception e){<BR> }<BR> }<BR></P>
<P>class Person{<BR> private int ID=-1;<BR> private String name;<BR> private String EMail;<BR> private int age;<BR> <BR> public void write(String name,String EMail,int age){<BR> this.name=name;<BR> this.EMail=EMail;<BR> this.age=age;<BR> }<BR> public void setRecordID(int ID){<BR> this.ID=ID;<BR> }<BR> public int getRecordID(){<BR> return ID;<BR> }<BR> public byte[] changeToByteArray(){<BR> byte[] data=null;<BR> <BR> try{<BR> ByteArrayOutputStream baos=new ByteArrayOutputStream();<BR> DataOutputStream dos=new DataOutputStream(baos);<BR> dos.writeUTF(name);<BR> dos.writeUTF(EMail);<BR> dos.writeInt(age);<BR> data=baos.toByteArray();<BR> <BR> baos.close();<BR> dos.close();<BR> }<BR> catch(Exception e){<BR> }<BR> return data;<BR> }<BR> <BR> public void changeFromByteArray(byte[] data){<BR> try{<BR> ByteArrayInputStream bais=new ByteArrayInputStream(data);<BR> DataInputStream dis=new DataInputStream(bais);<BR> name=dis.readUTF();<BR> EMail=dis.readUTF();<BR> age=dis.readInt();<BR> <BR> bais.close();<BR> dis.close();<BR> }<BR> catch(Exception e){<BR> }<BR> }<BR> public String getName(){<BR> return name;<BR> }<BR> public String getEMail(){<BR> return EMail;<BR> }<BR> public int getage(){<BR> return age;<BR> }<BR>}</P>
<P>class nameFilter implements RecordFilter{<BR> public boolean matches(byte[] candidate){<BR> DataInputStream person=new DataInputStream(new ByteArrayInputStream(candidate));<BR> String name="";<BR> String EMail="";<BR> int age=0;<BR> try{<BR> name=person.readUTF();<BR> EMail=person.readUTF();<BR> age=person.readInt();<BR> }<BR> catch(Exception e){<BR> }<BR> <BR> if(name.equals(Fourth.criteria))<BR> return true;<BR> else <BR> return false;<BR> }<BR>}</P> 空指针异常，自己再查一下
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