将包含整数属性的 bean 绑定到表单时，当显示表单时，该字段的值为 0，这是正常的，因为这是整数默认值。但是当我删除该字段的 0 并将焦点放在下一个表单字段（setImmediate = true）上时，我得到了一个令人讨厌的异常：
com.vaadin.data.Property$ConversionException: java.lang.reflect.InvocationTargetException
at com.vaadin.data.util.MethodProperty.convertValue(MethodProperty.java:695)
at com.vaadin.data.util.MethodProperty.setValue(MethodProperty.java:664)
at com.vaadin.ui.AbstractField.setValue(AbstractField.java:495)
at com.vaadin.ui.AbstractTextField.changeVariables(AbstractTextField.java:242)
at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.changeVariables(AbstractCommunicationManager.java:1460)
at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.handleVariableBurst(AbstractCommunicationManager.java:1404)
at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.handleVariables(AbstractCommunicationManager.java:1329)
at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.doHandleUidlRequest(AbstractCommunicationManager.java:761)
at com.vaadin.terminal.gwt.server.CommunicationManager.handleUidlRequest(CommunicationManager.java:318)
at com.vaadin.terminal.gwt.server.AbstractApplicationServlet.service(AbstractApplicationServlet.java:501)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:291)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.vaadin.data.util.MethodProperty.convertValue(MethodProperty.java:692)
... 22 more
Caused by: java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at java.lang.Integer.<init>(Unknown Source)
... 27 more
当然，我可以通过将字段设置为必填来避免这种情况，但这不是我想要的。我对 Vaadin 很陌生，所以我错过了什么吗？
谢谢