JSP：不评估 EL（而不是显示变量“$message”的值）

【问题标题】：JSP: EL is not evaluated (Instead of the value the variable "$message" is shown)JSP：不评估 EL（而不是显示变量“$message”的值）
【发布时间】：2015-11-19 14:51:14
【问题描述】：

我在评估 JSP 页面上的 EL 时遇到问题。 而不是值“Hello world！”我看到了变量“$message”。

我已尝试找到此问题的可能原因和解决方案：

  1. 应用服务器。检查了应用服务器 - 我使用的是 Tomcat 8.0.28 - 它应该支持 JSP 2.0。我还尝试从头开始创建一个新的简单 spring mvc 应用程序 - 并且在这种情况下评估了 EL。
  2. web.xml 描述符我使用“web-app_3_1.xsd”。
  3. 页面指令 isELIgnored 我尝试将此指令 () 添加到 JSP 页面，但情况变得更糟 - 这个表达式和整个 html 代码显示在页面。

  4. 我也尝试将以下代码添加到 web.xml 中

    <jsp-config>
<jsp-property-group>
    <url-pattern>*.jsp</url-pattern>
    <el-ignored>false</el-ignored>
</jsp-property-group>

没有什么帮助:)

也许问题可能与 pom.xml 有关，因为存在太多可能发生冲突的依赖关系。

非常感谢任何帮助。

project structure (image)

testController.jsp

package net.kuriculo.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
@RequestMapping("/test")
public class testController {
    @RequestMapping(method = RequestMethod.GET)
    public String printWelcome(ModelMap model) {
        model.addAttribute("message", "Hello world!");
        return "test";
    }
    }

test.jsp

<html>
<head>
    <title></title>
</head>
<body>
<h1>${message}</h1>
</body>
</html>

web.xml

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
         http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">

    <display-name>kuriculo</display-name>

    <servlet>
        <servlet-name>kuriculo</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>kuriculo</servlet-name>
        <url-pattern>*.jsp</url-pattern>
    </servlet-mapping>

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

</web-app>

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>net.kuriculo</groupId>
    <artifactId>kuriculo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>

    <properties>
        <!-- Spring Security is based on Spring 3.0.7 -->
        <!--<spring.version>3.2.8.RELEASE</spring.version>-->
        <spring.version>4.1.1.RELEASE</spring.version>
        <spring.security.version>3.2.3.RELEASE</spring.security.version>
        <jersey.version>1.18.1</jersey.version>
        <org.slf4j.version>1.7.7</org.slf4j.version>
        <org.hibernate.version>4.3.5.Final</org.hibernate.version>
        <maven-compiler-plugin.version>3.1</maven-compiler-plugin.version>
        <org.hsqldb.version>2.3.2</org.hsqldb.version>
        <commons-dbcp.version>1.4</commons-dbcp.version>
        <junit.version>4.11</junit.version>
        <org.eclipse.jetty.jetty-maven-plugin.version>9.1.1.v20140108</org.eclipse.jetty.jetty-maven-plugin.version>
    </properties>


    <licenses>
        <license>
            <name>The Apache Software License, Version 2.0</name>
            <url>http://www.apache.org/licenses/LICENSE-2.0.txt</url>
            <distribution>repo</distribution>
        </license>
    </licenses>

    <prerequisites>
        <maven>2.2.1</maven>
    </prerequisites>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>${maven-compiler-plugin.version}</version>
                <configuration>
                    <source>1.6</source>
                    <target>1.6</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.eclipse.jetty</groupId>
                <artifactId>jetty-maven-plugin</artifactId>
                <version>${org.eclipse.jetty.jetty-maven-plugin.version}</version>
            </plugin>
        </plugins>
    </build>

    <scm>
        <developerConnection>scm:git:https://github.com/nshkuratova/KURICULO.git</developerConnection>
    </scm>

    <dependencies>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!-- Huh? Spring Jdbc is suddenly marked as provided by spring-orm? -->
         <dependency>
             <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>com.sun.jersey.contribs</groupId>
            <artifactId>jersey-spring</artifactId>
            <version>${jersey.version}</version>
            <!-- jersey-spring uses spring 2.5, we want to use 3.x instead -->
            <exclusions>
                <exclusion>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-core</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-web</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-beans</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-context</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-aop</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>


        <dependency>
            <groupId>com.sun.jersey</groupId>
            <artifactId>jersey-json</artifactId>
            <version>${jersey.version}</version>
        </dependency>

        <dependency>
            <groupId>org.hsqldb</groupId>
            <artifactId>hsqldb</artifactId>
            <version>${org.hsqldb.version}</version>
        </dependency>

        <dependency>
            <groupId>commons-dbcp</groupId>
            <artifactId>commons-dbcp</artifactId>
            <version>${commons-dbcp.version}</version>
        </dependency>

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>${org.hibernate.version}</version>
        </dependency>

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>${org.slf4j.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-web</artifactId>
            <version>${spring.security.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-config</artifactId>
            <version>${spring.security.version}</version>
        </dependency>

<!--
        <dependency>
            <groupId>org.hibernate.common</groupId>
            <artifactId>hibernate-commons-annotations</artifactId>
            <version>${org.hibernate.version}</version>
        </dependency>-->

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring.version}</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>${junit.version}</version>
            <scope>test</scope>
        </dependency>

    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <version>1.4.187</version>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>${org.hibernate.version}</version>
    </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-expression</artifactId>
            <version>${spring.version}</version>
        </dependency>

    </dependencies>

</project>

【问题讨论】：

  • 尝试将@RequestMapping URL 更改为“/test”以外的其他内容。由于 JSP 也称为 test if 可能会导致命名冲突。
  • 我试图改变 - 问题仍然存在。不过，谢谢您的建议！

标签： jsp el


【解决方案1】：

在 web.xml 中，您的 servlet 定义缺少用于加载 spring 配置文件的 init-param。

<servlet>
    <servlet-name>kuriculo</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
         <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/kuriculo-servlet.xml</param-value>
    </init-param>    
<load-on-startup>1</load-on-startup>
</servlet>

同时删除 url-pattern "*.jsp" 并替换为 "/*" 

<servlet-mapping>
    <servlet-name>kuriculo</servlet-name>
    <url-pattern>/*</url-pattern>
</servlet-mapping>

【讨论】：

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