警告:#{} Generate.viewReportPDF:javax.el.PropertyNotFoundException:目标不可达,标识符“生成”解析为空
问题描述:
我真的很新的JSF但这里是我的问题:警告:#{} Generate.viewReportPDF:javax.el.PropertyNotFoundException:目标不可达,标识符“生成”解析为空
WARNING: #{Generate.viewReportPDF}: javax.el.PropertyNotFoundException: Target Unreachable, identifier 'Generate' resolved to null
我搜索,尝试了很多东西,但它没有工作,所以我要求你的帮助:
这是我 Generate.java在com.test包:
package com.test;
import javax.faces.context.FacesContext;
import javax.inject.Scope;
import javax.servlet.http.HttpServletResponse;
import javax.xml.transform.TransformerException;
import net.sf.jasperreports.engine.*;
import net.sf.jasperreports.engine.design.JasperDesign;
import net.sf.jasperreports.engine.xml.JRXmlLoader;
import javax.faces.bean.ManagedBean;
@ManagedBean
public class Generate {
...
public void viewReportPDF() throws IOException {
...
}
}
这里是我的web.xml(在WEB-INF中)
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
<context-param>
<param-name>javax.faces.PROJECT_STAGE</param-name>
<param-value>Development</param-value>
</context-param>
<context-param>
<param-name>javax.faces.CONFIG_FILES</param-name>
<param-value>/WEB-INF/faces-config.xml</param-value>
</context-param>
<servlet>
<servlet-name>Faces Servlet</servlet-name>
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>/faces/*</url-pattern>
</servlet-mapping>
<session-config>
<session-timeout>
30
</session-timeout>
</session-config>
<welcome-file-list>
<welcome-file>faces/init.jsp</welcome-file>
</welcome-file-list>
</web-app>
这里我faces-config.xml中(在WEB-INF):
<managed-bean>
<managed-bean-name>Generate</managed-bean-name>
<managed-bean-class>
com.test.Generate
</managed-bean-class>
<managed-bean-scope>session</managed-bean-scope>
</managed-bean>
这里我init.jsp:
<jsp:root version="1.2" xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:jsp="http://java.sun.com/JSP/Page">
<jsp:directive.page contentType="text/html;charset=UTF-8"
pageEncoding="UTF-8" />
<f:view>
<html>
<head>
<title>Test iReport With JSF</title>
</head>
<body style="background-color: #fff4db">
<h:form id="reportForm" target="report">
<h:commandButton id="pdfButton" value="Visualiser PDF"
styleClass="buttonStyle" action="#{Generate.viewReportPDF}" />
</h:form>
</body>
</html>
</f:view>
</jsp:root>
当我跑我有这样的错误:
警告:#{Generate.viewReportPDF}:javax.el.PropertyNotFoundExc eption:Target Unreachable,标识符'生成'解析为空
答
Java命名约定规定实例变量名称以小写字母开头。您需要使用#{generate.viewReportPDF}
而不是#{Generate.viewReportPDF}
。
如果你真的坚持使用一个大写的实例变量名(这是坏的),那么你可以随时将其覆盖在@ManagedBean
注释:
@ManagedBean(name="Generate")
@SessionScoped
public class Generate {
请注意,我说的@SessionScoped
注释,忘了那个。您还应该删除faces-config.xml
中多余且旧式的管理bean配置,该配置只会与注释冲突并覆盖它们。我还建议使用Facelets而不是古老的JSPX。
感谢您的帮助,但它仍然无效,我添加了@SessionScoped,并将'#{Generate.viewReportPDF}'重命名为'#{generate.viewReportPDF}'。现在我有与生成相同的错误,而不是生成。 – Louis 2012-02-28 19:23:03
我的不好!我删除了faces-config.xml中的托管bean配置,现在一切正常!谢谢 – Louis 2012-02-28 19:26:13
不客气:) – BalusC 2012-02-28 19:54:03