recordsort.java

rms常用操作例子,可通过这些例子修改成你想要的代码,绝对有用!

import java.io.*;
import javax.microedition.midlet.*;
import javax.microedition.rms.*;

public class RecordSort extends MIDlet{
  private RecordStore rs = null;
  static final String REC_STORE = "db_1";
 
  public RecordSort(){
    openRecStore();   // Create the Record Store
    
    // Write a few records
    writeRecord("Chinese");
    writeRecord("SiChuan");
    writeRecord("ChengDu");    
    writeRecord("BeiJing");        
 
    // Read back with enumerator, sorting the results
    readRecords();
    
    closeRecStore();  // Close Record Store
    deleteRecStore(); // Remove the Record Store
  }
 
  public void destroyApp( boolean unconditional ){}
 
  public void startApp(){
    // There is no user interface, go ahead and shutdown
    destroyApp(false);
    notifyDestroyed();
  }
 
  public void pauseApp(){}
 
  public void openRecStore(){
    try{
      // Create Record Store if it does not exist
      rs = RecordStore.openRecordStore(REC_STORE, true );
    }catch (Exception e){
      db(e.toString());
    }
  }    
  
  public void closeRecStore(){
    try{
      rs.closeRecordStore();
    }catch (Exception e){
      db(e.toString());
    }
  }
 
  public void deleteRecStore(){
    if (RecordStore.listRecordStores() != null){
      try{
        RecordStore.deleteRecordStore(REC_STORE);
      }catch (Exception e){
        db(e.toString());
      }
    }      
  }
 
  public void writeRecord(String str){
    byte[] rec = str.getBytes();
 
    try{
      rs.addRecord(rec, 0, rec.length);
    }catch (Exception e){
      db(e.toString());
    }
  }
 
  public void readRecords(){
    try{
      if (rs.getNumRecords() > 0){
        Comparator comp = new Comparator();
        
        RecordEnumeration re = rs.enumerateRecords(null, comp, false);
        while (re.hasNextElement()){
          String str = new String(re.nextRecord());
          System.out.println(str);
          System.out.println("------------------------------");                        
        }
      }
    }
    catch (Exception e){
         db(e.toString());
    }
  }
 
  /*--------------------------------------------------
  * Simple message to console for debug/errors
  *-------------------------------------------------*/
  private void db(String str){
    System.err.println("Msg: " + str);
  }
}
 
/*--------------------------------------------------
| Comparator.java
|
| Compares two records to determine sort order
*-------------------------------------------------*/
class Comparator implements RecordComparator{
  public int compare(byte[] rec1, byte[] rec2){
    String str1 = new String(rec1), str2 = new String(rec2);
    
    int result = str1.compareTo(str2);
    if (result == 0)
      return RecordComparator.EQUIVALENT;
    else if (result < 0)
      return RecordComparator.PRECEDES;
    else
      return RecordComparator.FOLLOWS;          
  }
}