【问题标题】:SQLite driver: Getting issue with getBinaryStream when Blob is nullSQLite 驱动程序:当 Blob 为空时,getBinaryStream 出现问题
【发布时间】:2015-06-19 10:25:37
【问题描述】:

当 blob 列在 db 上有空值时,getBinaryStream 方法出现问题,这是我的代码:

public void getAderent(int id ) throws IOException{
 String rq_getAdrent ="SELECT * FROM gss_aderent WHERE ad_id= '"+id+"' ";
 Image img=null; 

        try {
            dbConnection db = new dbConnection();
            Connection connect = db.connectiondb();
            connect.setAutoCommit(false);
            Statement stmt= connect.createStatement();    

            ResultSet rs = stmt.executeQuery(rq_getAdrent);  
          int i=0;
            while(rs.next())
            {
                      addadh_id.setText(rs.getInt("ad_id")+"");
                      addadh_prenom.setText( rs.getString("ad_fname"));
                      addadh_nom.setText(rs.getString("ad_lname"));
                      if(rs.getString("ad_sexe").equals("f")) addadh_sexe.setSelected(true); 
                      addadh_ddn.setText(rs.getString("ad_ddn"));
                      addadh_adresse.setText(rs.getString("ad_adresse"));
                      addadh_mobile.setText(rs.getString("ad_mobile"));
                      addadh_email.setText(rs.getString("ad_email"));
                      addadh_sante.setValue(rs.getString("ad_sante"));
                      addadh_taille.setText(rs.getDouble("ad_taille")+"");
                      addadh_poids.setText(rs.getDouble("ad_poids_initial")+"");
                      addadh_urgence_contact.setText(rs.getString("ad_urgence_contact"));                  


                      if(rs.getBinaryStream("ad_photo") != null)  
                          img = new Image(rs.getBinaryStream("ad_photo")); 
                      else 
                          img = new Image("proson.png" );                
                      addadh_adherent_photo.setImage(img);
                      addadh_adherent_photo_label.setText("photo définie");      
            }


            rs.close();
            stmt.close();
            connect.commit();
            connect.close();

            // msg.showMsg(stage, "information", "Information", "Vous avez selectionné l'adérent numéro : "+id);
        } catch (SQLException ex) {
            Logger.getLogger(Cons_aderentController.class.getName()).log(Level.SEVERE, null, ex);
        }


  }    

我得到了这个例外:

        Executing D:\backup\NetBeansProjects\JavaFx Projects\GssPro\dist\run1860540670\GssPro.jar using platform C:\Program Files\Java\jdk1.8.0_31\jre/bin/java
avr. 14, 2015 2:13:48 PM javafx.scene.control.Control loadSkinClass
SEVERE: No valid constructor defined in 'com.sun.javafx.scene.control.skin.ComboBoxBaseSkin' for control ComboBox[id=addadh_sante, styleClass=combo-box-base combo-box].
You must provide a constructor that accepts a single Skinnable (e.g. Control or PopupControl) parameter in com.sun.javafx.scene.control.skin.ComboBoxBaseSkin.
avr. 14, 2015 2:13:48 PM javafx.scene.control.Control loadSkinClass
SEVERE: No valid constructor defined in 'com.sun.javafx.scene.control.skin.ComboBoxBaseSkin' for control ComboBox[id=addadh_sante, styleClass=combo-box-base combo-box].
You must provide a constructor that accepts a single Skinnable (e.g. Control or PopupControl) parameter in com.sun.javafx.scene.control.skin.ComboBoxBaseSkin.
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
    at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1762)
    at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1645)
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
    at javafx.event.Event.fireEvent(Event.java:198)
    at javafx.scene.Scene$ClickGenerator.postProcess(Scene.java:3437)
    at javafx.scene.Scene$ClickGenerator.access$7900(Scene.java:3365)
    at javafx.scene.Scene$MouseHandler.process(Scene.java:3733)
    at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3452)
    at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1728)
    at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2461)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:348)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:273)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:382)
    at com.sun.glass.ui.View.handleMouseEvent(View.java:553)
    at com.sun.glass.ui.View.notifyMouse(View.java:925)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$141(WinApplication.java:102)
    at com.sun.glass.ui.win.WinApplication$$Lambda$37/584634336.run(Unknown Source)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
    at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1759)
    ... 30 more
Caused by: java.lang.NullPointerException
    at java.io.ByteArrayInputStream.<init>(ByteArrayInputStream.java:106)
    at org.sqlite.jdbc3.JDBC3ResultSet.getBinaryStream(JDBC3ResultSet.java:235)
    at org.sqlite.jdbc3.JDBC3ResultSet.getBinaryStream(JDBC3ResultSet.java:242)
    at controllers.Cons_aderentController.getAderent(Cons_aderentController.java:134)
    at controllers.Cons_aderentController.initData(Cons_aderentController.java:92)
    at controllers.Maj_aderentController.ConsultAderent(Maj_aderentController.java:177)
    ... 40 more

当 db 上的行没有 blob 列的空值时,一切都很好,但问题是当行具有空值时。我该如何解决这个问题?

PS: Cons_aderentController.java:134 对应:if(rs.getBinaryStream("ad_photo") != null)

【问题讨论】:

  • @James_D ,我认为它没有重复,我知道 NullPointerException 是什么,但我的问题是 SQLlite java 驱动程序中的 getBinaryStream 实现方法,尽管我已经测试了从我的方法获得的值当值为 null 时总是出现问题?
  • 你能编辑问题并显示哪一行给出了异常吗?
  • 问题出在行:if(rs.getBinaryStream("ad_photo") != null)
  • 你确定吗?该行可以抛出NullPointerException 的唯一方法是rsnull。您可以使用完整的堆栈跟踪来编辑您的问题吗?
  • @James_D ,不,我确定 rs 不是 null ,我只有在 blob 值为 null 时才会遇到这个问题,否则一切都很好。我认为方法 getInputStream 方法存在错误?怎么解决?

标签: java sqlite javafx nullpointerexception


【解决方案1】:

假设列名是正确的并且该列确实包含 SQL NULL 值(我认为这是根据您的描述的唯一可能性),那么看起来您的 JDBC 驱动程序没有正确实现 ResultSet 在此案子。 (我不是 sqlite 用户,但看起来这可能是known bug。)

作为一种(丑陋的)解决方法,请尝试

try {
    img = new Image(rs.getBinaryStream("ad_photo"));
} catch (Exception e) {
    img = new Image("proson.png" ); 
}

【讨论】:

  • 感谢@James_D,丑陋的解决方法已经解决了问题:p 我刚刚替换了:img = new Image("proson.png" ); img = new Image(getClass().getResourceAsStream("proson.png"));
  • 查看错误报告的链接,您可能会发现如果您获得最新版本的驱动程序,问题就解决了。这将是比使用try-catch 来实现逻辑更好的选择。
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