带有 JSTL 的 JSP 在 Spring Boot 应用程序中无法在 tomcat 8 上工作 [英] JSP with JSTL not working on tomcat 8 in a Spring Boot Application

问题描述

我在 pom.xml 中包含了这些依赖项.

I have include these dependency in pom.xml.

        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
        </dependency>

我仍然收到 javax.servlet.ServletException: java.lang.NoSuchMethodError: org.apache.el.lang.ELSupport.coerceToType(Ljavax/el/ELContext;Ljava/lang/Object;Ljava/lang/Class;)ljava/lang/Object;

Still i am getting javax.servlet.ServletException: java.lang.NoSuchMethodError: org.apache.el.lang.ELSupport.coerceToType(Ljavax/el/ELContext;Ljava/lang/Object;Ljava/lang/Class;)Ljava/lang/Object;

我还在 pom.xml 中添加了一个依赖项.

I also included one more dependency in pom.xml.

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-tomcat</artifactId>
        <scope>provided</scope>
    </dependency>

然后错误更改为 An exception occurred processing JSP page/WEB-INF/views/index.jsp at line 7 4: <%@ page session="false" %> [[[[ JSTL CODE USING EXPRESSION LANGUAGE]]]

Then the error changed to An exception occurred processing JSP page /WEB-INF/views/index.jsp at line 7 4: <%@ page session="false" %> [[[[ JSTL CODE USING EXPRESSION LANGUAGE]]]

在 eclipse ide 中一切正常，但无法在单独的 tomcat 服务器上进行部署.

Everything is working fine in eclipse ide but not working on deploying on separate tomcat server.

推荐答案

由于 tomcat-embed-el-8.0.32.jar 在您的 中的存在，您得到以下错误Tomcat 8.0\webapps\AppName\WEB-INF\lib 文件夹.

You are getting below error because of the presence of tomcat-embed-el-8.0.32.jar in your Tomcat 8.0\webapps\AppName\WEB-INF\lib folder.

javax.servlet.ServletException: java.lang.NoSuchMethodError:
org.apache.el.lang.ELSupport.coerceToType(Ljavax/el/ELContext;Ljava/lang/Object;Ljava/lang/Class;)Ljava/lang/Object;

此错误是由于Tomcat提供的ELSupport.class与tomcat-embed-el-8.0.32.jar冲突造成的> 存在于应用程序 lib 目录中，因此您会在 Tomcat 中遇到该错误.它在 Eclipse 中运行良好，因为它使用嵌入式服务器.

This error is due to the conflict between the ELSupport.class provided by Tomcat and tomcat-embed-el-8.0.32.jar present in the applications lib directory, hence you get that error in Tomcat. And it works fine in Eclipse since it uses embedded server.

要解决此问题，请在您的 pom.xml 中添加以下代码:

To fix this issue add below code in your pom.xml:

<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-el</artifactId>
    <scope>provided</scope>
</dependency>

当您将 tomcat-embed-el 依赖项添加为 scope=required 时，tomcat-embed-el-8.0.32.jar不会添加到您的 \AppName\WEB-INF\lib 文件夹中.

When you add tomcat-embed-el dependency as scope=required then the tomcat-embed-el-8.0.32.jar will not be added into your \AppName\WEB-INF\lib folder.

有关信息，请查看 Spring-Boot 的 Github 存储库上的此问题.

For information check this Issue on Spring-Boot's Github repository.

您也可以使用这些示例应用:

Also you can use these sample apps:

1. Spring-Boot-Jsp-Demo 已配置使用 InternalResourceViewResolver bean.
2. spring-boot-sample-tomcat-jsp 使用 application.properties 配置，就像在 spring-boot 示例应用程序中一样.

1. Spring-Boot-Jsp-Demo configured with InternalResourceViewResolver bean.
2. spring-boot-sample-tomcat-jsp configured with application.properties just like in the spring-boot sample apps.

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