Przekazywanie tablicy rekordów z Javy do procedury składowanej w Oracle’u

Poniżej znajduje się opis jak przekazywać string, tablicę stringów oraz tablicę par stringów z Javy do Oracle’a Należy utworzyć typy w bazie danych:

create or replace type VARCHAR2_PAIR as object( k varchar2(200), v varchar2(200));
create or replace type VARCHAR2_PAIRS_TABLE as table of VARCHAR2_PAIR;
create or replace type VARCHAR2_TABLE as table of VARCHAR2(200);

. Potem utworzyć procedurę składowaną

CREATE OR REPLACE PROCEDURE arrays_from_java(p_scalar varchar2
, p_array IN VARCHAR2_TABLE
, p_pairs_array in VARCHAR2_PAIRS_TABLE);

. A na końcu zawołać ją z Javy:

public static void callArrayProcedure() throws Exception{
    System.out.println("Preparing data");
    String[] list1=new String[2];
    list1[0] = "first string";
    list1[1] = "second string";

    String[][] list2=new String[2][];
    {
        String[] pair1 = new String[2];
        pair1[0] = "key1";
        pair1[1] = "value1";
        list2[0] = pair1;
    }
    {
        String[] pair2 = new String[2];
        pair2[0] = "key2";
        pair2[1] = "value2";
        list2[1] = pair2;
    }

    System.out.println("Preparing connection");
    SingleConnectionDataSource scds = new SingleConnectionDataSource();
    scds.setDriverClassName("oracle.jdbc.driver.OracleDriver");
    scds.setUrl("jdbc:oracle:thin:@host:1521:service_name");
    scds.setUsername(...);
    scds.setPassword(...);
    Connection conn = scds.getConnection();

    System.out.println("Preparing array of strings");
    ArrayDescriptor descriptor1 = ArrayDescriptor.createDescriptor("VARCHAR2_TABLE", conn );
    ARRAY arrayToPass1 = new ARRAY( descriptor1, conn, list1 );

    System.out.println("Preparing array of string pairs");
    ArrayDescriptor descriptor2 = ArrayDescriptor.createDescriptor("VARCHAR2_PAIRS_TABLE", conn );
    ARRAY arrayToPass2 = new ARRAY( descriptor2, conn, list2 );

    System.out.println("Calling procedure");
    OraclePreparedStatement ps = (OraclePreparedStatement) conn.prepareStatement( "{ call arrays_from_java( ?, ?, ? ) }" );
    ps.setString( 1, "string");
    ps.setARRAY( 2, arrayToPass1 );
    ps.setARRAY( 3, arrayToPass2 );
    ps.execute();
    ps.close();
}

.

Należy też dodać do classpath orai18n.jar, gdyż w przeciwnym wypadku jeśli baza nie będzie miała formatu UTF8 może występować błąd, że stringi się nullują podczas przekazywania do procedury

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Phonegap / Cordova and cross domain ssl request problem on android.

In one app I have participated, there was a use case:
  • User fill up a form.
  • User submit the form.
  • System send data via https to server and show a response.
During development there wasn’t any problem, but when we were going to release production version then some unsuspected situation occurred. I prepare the production version accordingly with standard flow for Android environment:
  • ant release
  • align
  • signing
During conduct tests on that version, every time I try to submit the form, a connection error appear. In that situation, at the first you should check whitelist in cordova settings. Every URL you want to connect to, must be explicit type in:
res/xml/cordova.xml
If whitelist looks fine, the error is most likely caused by inner implementation of Android System. The Android WebView does not allow by default self-signed SSL certs. When app is debug-signed the SSL error is ignored, but if app is release-signed connection to untrusted services is blocked.



Workaround


You have to remember that secure connection to service with self-signed certificate is risky and unrecommended. But if you know what you are doing there is some workaround of the security problem. Behavior of method
CordovaWebViewClient.onReceivedSslError
must be changed.


Thus add new class extended CordovaWebViewClient and override ‘onReceivedSslError’. I strongly suggest to implement custom onReceiveSslError as secure as possible. I know that the problem occours when app try connect to example.domain.com and in spite of self signed certificate the domain is trusted, so only for that case the SslError is ignored.

public class MyWebViewClient extends CordovaWebViewClient {

   private static final String TAG = MyWebViewClient.class.getName();
   private static final String AVAILABLE_SLL_CN
= "example.domain.com";

   public MyWebViewClient(DroidGap ctx) {
       super(ctx);
   }

   @Override
   public void onReceivedSslError(WebView view,
SslErrorHandler handler,
android.net.http.SslError error) {

String errorSourceCName = error.getCertificate().
getIssuedTo().getCName();

       if( AVAILABLE_SLL_CN.equals(errorSourceCName) ) {
           Log.i(TAG, "Detect ssl connection error: " +
error.toString() +
„ so the error is ignored”);

           handler.proceed();
           return;
       }

       super.onReceivedSslError(view, handler, error);
   }
}
Next step is forcing yours app to  use custom implementation of WebViewClient.

public class Start extends DroidGap
{
   private static final String TAG = Start.class.getName();

   @Override
   public void onCreate(Bundle savedInstanceState)
   {
       super.onCreate(savedInstanceState);
       super.setIntegerProperty("splashscreen", R.drawable.splash);
       super.init();

       MyWebViewClient myWebViewClient = new MyWebViewClient(this);
       myWebViewClient.setWebView(this.appView);

       this.appView.setWebViewClient(myWebViewClient);
       
// yours code

   }
}
That is all ypu have to do if minSdk of yours app is greater or equals 8. In older version of Android there is no class
android.net.http.SslError
So in class MyCordovaWebViewClient class there are errors because compliator doesn’t see SslError class. Fortunately Android is(was) open source, so it is easy to find source of the class. There is no inpediments to ‘upgrade’ app and just add the file to project. I suggest to keep original packages. Thus after all operations the source tree looks like:

Class SslError placed in source tree. 
 Now the app created in release mode can connect via https to services with self-signed SSl certificates.

Context menu or Action buttons ?

Recently I was drawn into one of those UI "religious" disputes that has no easy answers and usually both sides are right. One of our web developers was trying out new web tech (with pretty rich widget library) and started to question himself about some basic usability decisions. The low level problem in this case is usually brought to "which widget should I use ?". I'm not fond of bringing the usability problems to questions: Should I use Tabs over Menu ? Or should I use Context menu instead of buttons panel ? But sometimes if time is crucial factor and other usability levels are by default not addressed at all - better developer that asks those basic questions than developer that do not question himself at all.