java - 为什么我不能在自定义标记中使用 JSP EL？

标签 java jsp tags expression

当我在标记之外使用 ${} 表示表达式语言时，它可以处理数字或运算等。但是每当我将它作为值放入自定义标记中时，就会出现错误。我在互联网上检查了类似的问题并尝试了他们所有的解决方案，但没有一个起作用。顺便说一句，我只是在遵循tutorialspoint.com 上的教程，我相信我做的一切都是正确的。

这是显示的错误:

type Exception report

message /WEB-INF/view/itr.jsp (line: 72, column: 7) According to TLD or attribute directive in tag file, attribute value does not accept any expressions

description The server encountered an internal error that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: /WEB-INF/view/itr.jsp (line: 72, column: 7) According to TLD or attribute directive in tag file, attribute value does not accept any expressions
    org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:41)
    org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:275)
    org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:107)
    org.apache.jasper.compiler.Validator$ValidateVisitor.checkXmlAttributes(Validator.java:1241)
    org.apache.jasper.compiler.Validator$ValidateVisitor.visit(Validator.java:879)
    org.apache.jasper.compiler.Node$CustomTag.accept(Node.java:1536)
    org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2376)
    org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2428)
    org.apache.jasper.compiler.Validator$ValidateVisitor.visit(Validator.java:898)
    org.apache.jasper.compiler.Node$CustomTag.accept(Node.java:1536)
    org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2376)
    org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2428)
    org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2434)
    org.apache.jasper.compiler.Node$Root.accept(Node.java:464)
    org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2376)
    org.apache.jasper.compiler.Validator.validateExDirectives(Validator.java:1853)
    org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:217)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:356)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:336)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:323)
    org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:585)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:363)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    org.openmrs.web.filter.JspClassLoaderFilter.doFilter(JspClassLoaderFilter.java:47)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101)
    org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:168)
    org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:303)
    org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1228)
    org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1011)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:955)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.openmrs.module.web.filter.ForcePasswordChangeFilter.doFilter(ForcePasswordChangeFilter.java:60)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    org.openmrs.web.filter.GZIPFilter.doFilterInternal(GZIPFilter.java:64)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    org.openmrs.module.web.filter.ModuleFilterChain.doFilter(ModuleFilterChain.java:72)
    org.openmrs.module.owa.filter.OwaFilter.doFilter(OwaFilter.java:57)
    org.openmrs.module.web.filter.ModuleFilterChain.doFilter(ModuleFilterChain.java:70)
    org.openmrs.module.web.filter.ModuleFilter.doFilter(ModuleFilter.java:54)
    org.openmrs.web.filter.OpenmrsFilter.doFilterInternal(OpenmrsFilter.java:108)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    org.springframework.orm.hibernate4.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:150)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    org.openmrs.web.filter.StartupFilter.doFilter(StartupFilter.java:105)
    org.openmrs.web.filter.StartupFilter.doFilter(StartupFilter.java:105)
    org.openmrs.web.filter.StartupFilter.doFilter(StartupFilter.java:105)
    org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)

这些是我的代码:

HelloTag.java

package org.openmrs.web.taglib;

import javax.servlet.jsp.tagext.*;
import javax.servlet.jsp.*;
import java.io.*;

public class HelloTag extends SimpleTagSupport {

    private double value;

    public void setValue(double val) {
        this.value = val;
    }

    StringWriter sw = new StringWriter();

    public void doTag() throws JspException, IOException {
        if (value != 0) {
            /* Use message from attribute */
            JspWriter out = getJspContext().getOut();
            out.println( value );
        }
        else {
            /* use message from the body */
            getJspBody().invoke(sw);
            getJspContext().getOut().println(sw.toString());
        }
    }
}

自定义.tld

<taglib>
  <tlib-version>1.0</tlib-version>
  <jsp-version>1.2</jsp-version>
  <short-name>Example TLD</short-name>
  <uri>http://java.sun.com/jsp/jstl/core_rt</uri>
  <tag>
    <name>Hello</name>
    <tag-class>org.openmrs.web.taglib.HelloTag</tag-class>
    <body-content>scriptless</body-content>
    <attribute>
       <name>value</name>
    </attribute>
  </tag>
</taglib>

itr.jsp

<%@ include file="/WEB-INF/view/module/chitscore/template/include.jsp" %>
<%@ page isELIgnored="false" %>

<h1>Individual Treatment Record</h1>

<h3>Anthropometric Data</h3>
<c:set var="OPENMRS_VIEWING_PATIENT_ID" scope="request" value="${patient.patientId}"/>
<form:form action="anthropometricdata.form" method="POST" modelAttribute="anthropometricdata">
    <table>
        <form:input path="patientId" type="hidden" value="${patient.patientId}"/>
        <tr>
            <td>Height</td>
            <td><form:input path="height" /></td>
        </tr>
        <tr>
            <td>Weight</td>
            <td><form:input path="weight" /></td>
        </tr>
        <tr>
            <td>Body Mass Index</td>
            <td></td>
        </tr>
        <tr>
            <td>Waist Circumference</td>
            <td><form:input path="waistCircumference" /></td>
        </tr>
        <tr>
            <td>Hip Circumference</td>
            <td><form:input path="hipCircumference" /></td>
        </tr>
        <tr>
            <td>Waist-Hip Ratio</td>
            <td></td>
        </tr>
        <tr>
            <td>Head Circumference</td>
            <td><form:input path="headCircumference" /></td>
        </tr>
        <tr>
            <td>Chest Circumference</td>
            <td><form:input path="chestCircumference" /></td>
        </tr>
        <tr>
            <td colspan="2">
                <input type="submit" name="action" value="Save" />
                <input type="submit" name="action" value="Cancel" />
            </td>
        </tr>
    </table>
</form:form>
<br>
<table border="1">
    <th>Height</th>
    <th>Weight</th>
    <th>Body Mass Index</th>
    <th>Waist Circumference</th>
    <th>Hip Circumference</th>
    <th>Waist-Hip Ratio</th>
    <th>Head Circumference</th>
    <th>Chest Circumference</th>
    <th>test</th>
    <c:forEach items="${anthropometricdataList}" var="anthropometricdata">
        <tr>
            <td>${anthropometricdata.height}</td>
            <td>${anthropometricdata.weight}</td>
            <td>${anthropometricdata.bmi}</td>
            <td>${anthropometricdata.waistCircumference}</td>
            <td>${anthropometricdata.hipCircumference}</td>
            <td>${anthropometricdata.waistHipRatio}</td>
            <td>${anthropometricdata.headCircumference}</td>
            <td>${anthropometricdata.chestCircumference}</td>
            <td><ex:Hello value="${ anthropometricdata.weight }"/>${1 + 2 }</td>
        </tr>
    </c:forEach>
</table>

<%@ include file="/WEB-INF/view/module/chitscore/template/footer.jsp" %>

最佳答案

根据Java EE Tutorial ，您必须将标记的 rtexprvalue 设置为 true。即

<attribute>
   <name>value</name>
   <rtexprvalue>true</rtexprvalue>
</attribute>

关于java - 为什么我不能在自定义标记中使用 JSP EL？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/43261809/

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