rms_ex3.java

J2ME 无线通信技术应用开发源代码

//程序名RMS_Ex3.java，项目RMS_Ex3
//测试多个记录存储的相互引用
import javax.microedition.midlet.*;
import javax.microedition.rms.*;

public class RMS_Ex3 extends MIDlet {
  RecordStore rs_boss = null;
  RecordStore rs_me = null;
  String oneday_boss, oneday_me; //分别用来添加的数据

  public RMS_Ex3() {
    try {
      //这里可以不删除rs_boss和,rs_me，把下面两行注释掉即可。这样能看到添加多条记录时的效果
      //RecordStore.deleteRecordStore("rs_boss");
      //RecordStore.deleteRecordStore("rs_me");
      rs_boss = RecordStore.openRecordStore("rs_boss", true );
      rs_me = RecordStore.openRecordStore("rs_me", true );
    } catch( Exception e ){
      // ignore any errors...
    }
  }
  
  public void startApp() {
    String oneday_boss = "A meeting at GreatWall Hotel, 8:00AM";
    String oneday_me = "Visit my friend, 7:00PM";
    String for_test = "for test...";
    try {
      byte[] nothing = changeToRecord(0, for_test);
      rs_me.addRecord(nothing, 0, nothing.length);
      
      int index_me = rs_me.getNextRecordID();
      byte[] arrange_boss = changeToRecord(index_me, oneday_boss);
      int intdex_boss = rs_boss.addRecord(arrange_boss, 0, arrange_boss.length);
      byte[] arrange_me = changeToRecord(intdex_boss, oneday_me);
      rs_me.addRecord(arrange_me, 0, arrange_me.length);
    //查看效果
      System.out.println("====================");
      int num = rs_boss.getNumRecords();
      for (int i = 1;i<=num;i++) {
        byte[] temp = rs_boss.getRecord(i);
        System.out.println("rs_boss recordID "+i+" : "+new String(temp,1,temp.length-1)+" Reference to me --> "+(int)temp[0]);
      }

      num = rs_me.getNumRecords();
      for (int i = 1;i<=num;i++) {
        byte[] temp = rs_me.getRecord(i);//new byte[rs_boss.getRecordSize(i)];
        System.out.println("rs_me   recordID "+i+" : "+new String(temp,1,temp.length-1)+" Reference to boss --> "+(int)temp[0]);
      }
    } catch(RecordStoreException e ){
      System.out.println("error , program exist.");
      notifyDestroyed();//发生错误，关闭应用程序
    }
    notifyDestroyed();//运行结束即关闭应用程序
  }

  public void pauseApp() {
  }

  public void destroyApp( boolean unconditional ) {
  }
  
  private byte[] changeToRecord(int index, String str) {
    int len = str.length();
	  byte[] b =new byte[1+len];
	  b[0] = (byte)index;
	  byte[] str_b = str.getBytes();
	  for (int i = 0;i < len;i++) {
	    b[i+1] = str_b[i];
	  }
	  return b;
  }
}