JSFのconvertDateTimeでCannot format given Object as a Dateとなった時の対応方法

• 環境
  • Windows10 64bit バージョン1909
  • openjdk 11 2018-09-25
  • Eclipse IDE for Enterprise Java Developers Version: 2020-03 (4.15.0)
  • JSF 2.3.9

事象 : f:convertDateTimeを使ったらエラーになった

2020-07-20 09:49:54:387 X-TrackingId:6079d04e-6554-492e-b2be-e01eed06        ERROR   MyExceptionHandler.handle:63 Cannot format given Object as a Date
java.lang.IllegalArgumentException: Cannot format given Object as a Date
        at java.base/java.text.DateFormat.format(DateFormat.java:338)
        at java.base/java.text.Format.format(Format.java:158)
        at javax.faces.convert.DateTimeConverter$FormatWrapper.format(DateTimeConverter.java:495)
        at javax.faces.convert.DateTimeConverter$FormatWrapper.access$300(DateTimeConverter.java:470)
        at javax.faces.convert.DateTimeConverter.getAsString(DateTimeConverter.java:544)
        at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.getFormattedValue(HtmlBasicRenderer.java:491)
        at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.getFormattedValue(HtmlBasicRenderer.java:509)
        at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.getCurrentValue(HtmlBasicRenderer.java:330)
        at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeEnd(HtmlBasicRenderer.java:143)
        at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:595)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1654)
        at com.sun.faces.facelets.component.RepeatRenderer.encodeChildren(RepeatRenderer.java:64)
        at com.sun.faces.facelets.component.UIRepeat.process(UIRepeat.java:559)
        at com.sun.faces.facelets.component.UIRepeat.encodeChildren(UIRepeat.java:1068)
        at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeRecursive(HtmlBasicRenderer.java:278)
        at com.sun.faces.renderkit.html_basic.GroupRenderer.encodeChildren(GroupRenderer.java:90)
        at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:566)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1647)
        at javax.faces.render.Renderer.encodeChildren(Renderer.java:152)
        at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:566)

  <h:outputText value="#{bean.myTimestamp}" >
     <f:convertDateTime pattern="yyyy/MM/dd HH:mm" timeZone="Japan" />
  </h:outputText>

原因 : 変換対象の日付がLocalDateTimeだから

    bean.setMyTimestamp(LocalDateTime.now());

対応 : typeに「localDateTime」を指定する

Specifies what contents the string value will be formatted to include, or parsed expecting. Valid values are "date", "time", "both", "localDate", "localDateTime", "localTime", "offsetTime", "offsetDateTime", and "zonedDateTime".
convertDateTime (JSF 2.3 View Declaration Language: Facelets Variant, generated with VDLDoc.)

こうするとうまくいく

  <h:outputText value="#{bean.myTimestamp}" >
     <f:convertDateTime pattern="yyyy/MM/dd HH:mm" timeZone="Japan" type="localDateTime" />
  </h:outputText>

なんか注意されるのは気になる・・・

他の対応

やってないけどいつかのために

• 独自のConverterを作成する
  • java - f:convertDateTime support for Java8 LocalDate / LocalDateTime? - Stack Overflow
• LocalDateTimeをDateに変換して使う
  • Java8 LocalDateTimeと旧Dateの相互変換 - 気軽に楽しくプログラムと遊ぶ
• LocalDateTimeを使うのをやめる(古い世界に閉じこもる)