javax.el.PropertyNotFoundException： 属性'foo'在 java.lang.Boolean 类型上不可读

Question

我有一个看起来像这样的类：

public class ScoreDefinition {
    protected Boolean primary;
    public Boolean isPrimary() {
        return primary;
    }
    public void setPrimary(Boolean value) {
        this.primary = value;
    }
}

我试图在EL中访问其primary属性：

<c:forEach var="score" items="${scores}">
    <input type="checkbox"
           value="${score.primary}"
           name="someName"
           class="textField"/>
</c:forEach>

但是我得到了例外：

javax.el.PropertyNotFoundException: Property 'primary' not readable on type java.lang.Boolean
    at javax.el.BeanELResolver$BeanProperty.read(BeanELResolver.java:280)
    at javax.el.BeanELResolver$BeanProperty.access$000(BeanELResolver.java:230)
    at javax.el.BeanELResolver.getValue(BeanELResolver.java:81)
    at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:54)
    at org.apache.el.parser.AstValue.getValue(AstValue.java:123)
    at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:186)
    at org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextImpl.java:938)
    at org.apache.jsp.WEB_002dINF.views.administer.projectBlocks_jsp._jspx_meth_c_005fforEach_005f2(projectBlocks_jsp.java:806)
    at org.apache.jsp.WEB_002dINF.views.administer.projectBlocks_jsp._jspx_meth_c_005fif_005f2(projectBlocks_jsp.java:709)
    at org.apache.jsp.WEB_002dINF.views.administer.projectBlocks_jsp._jspx_meth_form_005fform_005f0(projectBlocks_jsp.java:245)
    at org.apache.jsp.WEB_002dINF.views.administer.projectBlocks_jsp._jspService(projectBlocks_jsp.java:150)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    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.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:436)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:374)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302)
    at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
    at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:262)
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1180)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:950)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    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 com.groupgti.webclient.filter.SecurityFilter.doFilter(SecurityFilter.java:51)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at com.groupgti.webclient.filter.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:43)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    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:293)
    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(Thread.java:662)

我无法更改此类，因为它是从WSDL文件生成的。因此，问题是如何解决此问题，不使用任何自定义EL功能将Boolean转换为String或不将此对象转换为我的问题？是否可以以某种方式在EL中以某种方式阅读此属性而没有任何其他修改？

Answer 1

is前缀仅适用于boolean，而不是Boolean。

您有2个选项：

1. 使用boolean代替Boolean。

2. 或重命名方法isPrimary()至getPrimary()。

关于JAXB的自动化方法错误，您需要升级至至少jaxb 2.1.13或根据此Jaxb文档将-B-enableIntrospection添加到WSIMPORT调用中。

另请参见：

• Javabeans规范 - 第8.3.2章
• Java表达语言如何解决布尔属性？（在JSF 1.2中）
• JSF 2个复选框和布尔甘特斯

Answer 2

您可以直接使用呼叫 score.isprimary（）这样：

<c:forEach var="score" items="${scores}">
<input type="checkbox"
       value="${score.isPrimary()}"
       name="someName"
       class="textField"/>
</c:forEach>