//省略import
@PersistenceCapable(identityType = IdentityType.APPLICATION, detachable="true")
public class data_account {

@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
@Extension(vendorName="datanucleus", key="gae.encoded-pk", value="true")
private String encodedKey; //編碼的Key,自動產生

@Persistent
@Extension(vendorName="datanucleus" , key="gae.pk-id", value="true")
private Long id; //自動產生

@Persistent
private String account;

@Persistent
private Date date = new Date();

@Persistent(mappedBy = "da")  //這裡名稱是對應到data_plurk裡面的data_account xx這個名稱
List  data_plurks;  //一對多關係的標註

//setter省略
//getter也省略

}

@PersistenceCapable(identityType = IdentityType.APPLICATION, detachable="true")
public class data_plurk {

@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
@Extension(vendorName="datanucleus", key="gae.encoded-pk", value ="true")
private String encodedKey; //編碼的Key,//自動產生

@Persistent
@Extension(vendorName="datanucleus", key="gae.pk-id", value="true")
private Long id;//自動產生

@Persistent
private String content;

@Persistent
@Extension(vendorName="datanucleus", key="gae.parent-pk", value="true")
private Key plurkKey;  //父類別的設置

@Persistent
private data_account da;  //一對一關係的標註

//setter省略
//getter也省略

public class toInsert extends HttpServlet {
public void doPost(HttpServletRequest req, HttpServletResponse resp)
  throws IOException {

 PersistenceManager pm = PMF.get().getPersistenceManager();
 try {
  data_account da = new data_account();
  da.setAccount("test");
  da.setDate(new Date());
  pm.makePersistent(da);           
  Key daKey = KeyFactory.stringToKey(da. getEncodedKey());

  data_plurk dp1 = new data_plurk();
  dp1.setConten("hi");
  dp1.setEmployee (da);
  dp1.setKey(daKey);                      //將data_account設為父類別
  da.getPlurkSets().add(dp1);        //保證data_account的一對多
  pm.makePersistent(dp1);           


  data_plurk dp2 = new data_plurk();
  dp2 .setConten("hi");
  dp2 .setEmployee (da);
  dp2 .setKey(daKey);                      //將data_account設為父類別
  da.getPlurkSets().add(dp2 );        //保證data_account的一對多
  pm.makePersistent(dp2 );              

 }catch(Exception e){
  resp.getWriter().println(e.toString());
 }finally {
  pm.close();
 }
}
}

想在android裡面開發有關map應用 

必須先去申請map key!

請先打開eclipse

接著點選windows->preferences->android->build

找到Default debug keystore，把位置複製下來。

接著打開cmd..

然後cd 到java/jdk/bin目錄底下，輸入下面指令

keytool.exe -list -alias androiddebugkey -keystore "C:\Users\ken\.android\debug.keystore" -storepass android -keypass android

接著會回傳一段MD5過後的結果!

請複製下來!

接著到

http://code.google.com/intl/zh-TW/android/maps-api-signup.html

此處去登記!

即可得到map API key!!!

（切記！！！上面的紅色的參數，都是Android預設的，也就是說這把key只能用在本機開發測試用！因為要上傳至Android Market會自己create一把key，然後用那把key去sigin and export出來，所以預設的key和自己create的key所產生的md5結果會不同）

<?xml version="1.0" encoding="utf-8"?>
<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"  
  android:minWidth="146dip"  
  android:minHeight="146dip"  
  android:updatePeriodMillis="1000"  
  android:initialLayout="@layout/analog_appwidget" >  
</appwidget-provider>  

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout
  android:id="@+id/LinearLayout01"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  xmlns:android="http://schemas.android.com/apk/res/android">
   
    <TextView
      android:id="@+id/TextView01"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="efefefefefef">
    </TextView>
</LinearLayout>

 
 <receiver android:name="AnalogAppWidgetProvider" >   
        <intent-filter>   
          <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />   
        </intent-filter>   
        <meta-data android:name="android.appwidget.provider"    
                   android:resource="@xml/analog_appwidget" />   
 </receiver>  
 

   
 //import省略   
public class AnalogAppWidgetProvider extends AppWidgetProvider { 
    
   Context context_main ; 
   AppWidgetManager app_manager; 
   int []appWidgetId; 
    
   @Override 
   public void onUpdate(Context context, AppWidgetManager appWidgetManager, 
     int[] appWidgetIds) { 
    super.onUpdate(context, appWidgetManager, appWidgetIds); 
     
    app_manager = appWidgetManager; 
    context_main = context; 
    appWidgetId = appWidgetIds; 
     
       Thread thread = new Thread(new update_thread()); 
       thread.start(); 
 
   } 
    
   public class update_thread implements Runnable{ 
    @Override 
    public void run() { 
     int i = 0; 
     while(true && i++ <100){ 
       RemoteViews views = 
 new RemoteViews(context_main.getPackageName(), R.layout.analog_appwidget); 
       views.setTextViewText(R.id.TextView01, String.valueOf(Math.random()) ); 
 
       app_manager.updateAppWidget(appWidgetId, views); 
     }       
    }      
   } 
 
}