四、J2ME简单的行情软件--RMS

J2ME中的rms在这的用途:

在进行这个行情软件开发的时候，在开发行情列表的时候，

用户可以定制自己要显示的字段("代码","昨收","最高","最低","成交量","成交额","振幅","今开"),我让程序默认的显示了("最新","涨幅","涨跌"),并且还对这些字段要用到按照一定的顺序进行排列，我用到了RMS那进行开发。我将这些字段都是用类的形式储存到rms中

 

实例类:

public class ShowQuotesCategory {
 private int index;
 private String name;
 
 public ShowQuotesCategory(){
 }
 
 public ShowQuotesCategory(int index,String name){
  this.index=index;
  this.name=name;
 }
 
 public int getIndex() {
  return index;
 }
 public void setIndex(int index) {
  this.index = index;
 }
 public String getName() {
  return name;
 }
 public void setName(String name) {
  this.name = name;
 }
 
 public byte[] object2ByteArray() throws Exception{
  ByteArrayOutputStream baos=new ByteArrayOutputStream();
  DataOutputStream dos=new DataOutputStream(baos);
  
  dos.writeInt(this.index);
  dos.writeUTF(this.name);
  baos.close();
  dos.close();
  return baos.toByteArray();
 }
 
 public static ShowQuotesCategory byteArray2Object(byte[] b) throws Exception{
  ByteArrayInputStream bais=new ByteArrayInputStream(b);
  DataInputStream dis=new DataInputStream(bais);
  
  ShowQuotesCategory fenshiCategory=new ShowQuotesCategory();
  fenshiCategory.setIndex(dis.readInt());
  fenshiCategory.setName(dis.readUTF());
  bais.close();
  dis.close();
  
  return fenshiCategory;
 }

}

 

下面的为对字段进行排序的类:

public class ShowQuotesCategoryComparator implements RecordComparator {

 public int compare(byte[] b1, byte[] b2) {
  try {
   ShowQuotesCategory f1=ShowQuotesCategory.byteArray2Object(b1);
   ShowQuotesCategory f2=ShowQuotesCategory.byteArray2Object(b2);
   
   if(f1.getIndex()>f2.getIndex()){
    return RecordComparator.FOLLOWS;
   }else if(f1.getIndex()<f2.getIndex()){
    return RecordComparator.PRECEDES;
   }else{
    return RecordComparator.EQUIVALENT;
   }
  } catch (Exception e) {
   e.printStackTrace();
  }
  return 0;
 }
 
}

 

在添加字段的时候，我还要查找该字段有没有存在，我到网上查了一下都说，把数据全部删了，再添加所有的数据这样比较快:

RMS的操作类如下:

public class RecordUtil {
 
 private static RecordUtil instance;
 private static RecordStore rs;
 private RecordEnumeration re;
 private  Vector vector;
 private static ShowQuotesCategory sqc;
 
 /**
  * 实例化RecordStore对象，并在rs中存入几个值
  * @param storeName
  * @return
  */
 public static RecordUtil getInstance(String storeName){
  if(instance==null){
   try {
    rs=RecordStore.openRecordStore(storeName, true);
    sqc=new ShowQuotesCategory();
    //添加几个默认的值
    if(rs.getNumRecords()<=0){
     byte[] b;
     b=Resources.CATEGORY_QUOTEST_LIST_ZUIXIN.object2ByteArray();
     rs.addRecord(b, 0, b.length);

     b=Resources.CATEGORY_QUOTEST_LIST_ZHANGFU.object2ByteArray();
     rs.addRecord(b, 0, b.length);

     b=Resources.CATEGORY_QUOTEST_LIST_ZHANGDIE.object2ByteArray();
     rs.addRecord(b, 0, b.length);
    }
   } catch (Exception e) {
    e.printStackTrace();
   }
   instance=new RecordUtil();
  }
  return instance;
 }
 
 
 public String getStortName(){
  if(rs!=null){
   try {
    return rs.getName();
   } catch (RecordStoreNotOpenException e) {
    e.printStackTrace();
   }
  }
  return null;
 }
 
 public Vector getRecord(RecordFilter rf,RecordComparator rc,boolean flag){
  if(rs!=null){
   vector=new Vector();
   try {
    re=rs.enumerateRecords(rf, rc, flag);
    while(re.hasNextElement()){
     sqc=ShowQuotesCategory.byteArray2Object(re.nextRecord());
     vector.addElement(sqc);
    }
    return vector;
   } catch (Exception e) {
    e.printStackTrace();
   }
  }
  return null;
 }
 
 /**
  * 添加数据到rms,在执行这一步的时候一定要先删除掉这个结果集
  *
  */
 public Vector addRecord(Vector v,RecordFilter rf,RecordComparator rc,boolean flag){
  if(rs!=null){
   try {
    String name=getStortName();
    closeRecord();
    RecordStore.deleteRecordStore(name);
    rs=RecordStore.openRecordStore(name, true);
    //添加几个默认的值
    if(rs.getNumRecords()<=0){
     byte[] b;
     b=Resources.CATEGORY_QUOTEST_LIST_ZUIXIN.object2ByteArray();
     rs.addRecord(b, 0, b.length);

     b=Resources.CATEGORY_QUOTEST_LIST_ZHANGFU.object2ByteArray();
     rs.addRecord(b, 0, b.length);

     b=Resources.CATEGORY_QUOTEST_LIST_ZHANGDIE.object2ByteArray();
     rs.addRecord(b, 0, b.length);
    }
    if(v.size()>0){
     for (int i = 0; i < v.size(); i++) {
      sqc=(ShowQuotesCategory)v.elementAt(i);
      rs.addRecord(sqc.object2ByteArray(), 0, sqc.object2ByteArray().length);
     }
    }
    return this.getRecord(rf, rc, flag);
   } catch (Exception e) {
    e.printStackTrace();
   }
  }
  return null;
 }
 
 public void closeRecord(){
  if(rs!=null){
   try {
    rs.closeRecordStore();
   } catch (Exception e) {
    e.printStackTrace();
   }
  }
 }
}