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Struts 2 convention plugin not working !.How to get it running?

由 大憨熊 提交于 2021-01-29 06:50:52

问题


I have tried to use the Struts 2 convention plugin using the tutorial on the official documentation but I can't get it to run.

Here's how I have configured it:

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>Struts2Convention</groupId>
  <artifactId>Struts2Convention</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  <build>
    <sourceDirectory>src</sourceDirectory>
    <plugins>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.8.0</version>
        <configuration>
          <release>9</release>
        </configuration>
      </plugin>
      <plugin>
        <artifactId>maven-war-plugin</artifactId>
        <version>3.2.1</version>
        <configuration>
          <warSourceDirectory>WebContent</warSourceDirectory>
        </configuration>
      </plugin>
    </plugins>
  </build>


  <dependencies>

  <dependency>
    <groupId>postgresql</groupId>
        <artifactId>postgresql</artifactId>
        <version>9.1-901-1.jdbc4</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.apache.struts/struts2-core -->
<dependency>
    <groupId>org.apache.struts</groupId>
    <artifactId>struts2-core</artifactId>
    <version>2.5.20</version>
</dependency>

<!-- https://mvnrepository.com/artifact/commons-logging/commons-logging -->
<dependency>
    <groupId>commons-logging</groupId>
    <artifactId>commons-logging</artifactId>
    <version>1.2</version>
</dependency>




    <!-- https://mvnrepository.com/artifact/commons-logging/commons-logging-api -->
<dependency>
    <groupId>commons-logging</groupId>
    <artifactId>commons-logging-api</artifactId>
    <version>1.1</version>
</dependency>



<!-- https://mvnrepository.com/artifact/org.apache.struts/struts2-convention-plugin -->
 <dependency>
    <groupId>org.apache.struts</groupId>
    <artifactId>struts2-convention-plugin</artifactId>
    <version>2.5.20</version>
</dependency> 

  </dependencies>
</project>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" id="WebApp_ID" version="4.0">
  <display-name>Struts2Convention</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>

  <filter>
  <filter-name>struts2</filter-name>
  <filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter</filter-class>
  </filter>

  <filter-mapping>
   <filter-name>struts2</filter-name>
   <url-pattern>/*</url-pattern>
  </filter-mapping>


</web-app>

I have created the following files as per the tutorial hello-world.jsp and HelloWorld.java which is the action class.

HelloWorld.java 

package com.example.actions;

import org.apache.struts2.convention.annotation.Action;

import com.opensymphony.xwork2.ActionSupport;

    public class HelloWorld extends ActionSupport {
      private String message;

      public String getMessage() {
        return message;
      }

      public String execute() {
        message = "Hello World!";
        return SUCCESS;
      }
    }

hello-world.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
hello world!
</body>
</html>

As per the documentation ,

First the Convention plugin finds packages named struts, struts2, action or actions. Any packages that match those names are considered the root packages for the Convention plugin. Next, the plugin looks at all of the classes in those packages as well as sub-packages and determines if the classes implement com.opensymphony.xwork2.Action or if their name ends with Action (i.e. FooAction).

My setup looks like this

Project Setup

project setup

I am getting the following error while running tomcat: 

ERROR DefaultClassFinder Unable to read class [com.example.actions.HelloWorld]
 java.lang.IllegalArgumentException
    at org.objectweb.asm.ClassReader.<init>(Unknown Source)
    at org.objectweb.asm.ClassReader.<init>(Unknown Source)
    at org.objectweb.asm.ClassReader.<init>(Unknown Source)
    at org.apache.struts2.convention.DefaultClassFinder.readClassDef(DefaultClassFinder.java:461)
    at org.apache.struts2.convention.DefaultClassFinder.<init>(DefaultClassFinder.java:93)
    at org.apache.struts2.convention.PackageBasedActionConfigBuilder.buildClassFinder(PackageBasedActionConfigBuilder.java:395)
    at org.apache.struts2.convention.PackageBasedActionConfigBuilder.findActions(PackageBasedActionConfigBuilder.java:377)
    at org.apache.struts2.convention.PackageBasedActionConfigBuilder.buildActionConfigs(PackageBasedActionConfigBuilder.java:333)
    at org.apache.struts2.convention.ClasspathPackageProvider.loadPackages(ClasspathPackageProvider.java:52)
    at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:206)
    at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:66)
    at org.apache.struts2.dispatcher.Dispatcher.getContainer(Dispatcher.java:957)
    at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:463)
    at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:496)
    at org.apache.struts2.dispatcher.InitOperations.initDispatcher(InitOperations.java:73)
    at org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:61)
    at org.apache.catalina.core.ApplicationFilterConfig.initFilter(ApplicationFilterConfig.java:270)
    at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:251)
    at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:102)
    at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4516)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5162)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1377)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1367)
    at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
    at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
    at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:140)
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:902)
    at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:831)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1377)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1367)
    at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
    at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
    at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:140)
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:902)
    at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
    at org.apache.catalina.core.StandardService.startInternal(StandardService.java:423)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
    at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:928)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
    at org.apache.catalina.startup.Catalina.start(Catalina.java:638)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:564)
    at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:350)
    at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:492)

and my page doesn't load. I get HTTP status 404 error.

How can I fix this?


回答1:


I changed pom.xml to exclude asm 5.2 and include asm 7.1 . It's mentioned in this link that there is a bug which causes this problem in java 9,10,11.

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>Struts2Convention</groupId>
	<artifactId>Struts2Convention</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>war</packaging>
	<build>
		<sourceDirectory>src</sourceDirectory>
		<plugins>
			<plugin>
				<artifactId>maven-compiler-plugin</artifactId>
				<version>3.8.0</version>
				<configuration>
					<release>9</release>
				</configuration>
			</plugin>
			<plugin>
				<artifactId>maven-war-plugin</artifactId>
				<version>3.2.1</version>
				<configuration>
					<warSourceDirectory>WebContent</warSourceDirectory>
				</configuration>
			</plugin>
		</plugins>
		<resources>
     <resource>
       <directory>src</directory>
     </resource>
   </resources>
	</build>


	<dependencies>

		<dependency>
			<groupId>postgresql</groupId>
			<artifactId>postgresql</artifactId>
			<version>9.1-901-1.jdbc4</version>
		</dependency>

		<!-- https://mvnrepository.com/artifact/org.apache.struts/struts2-core -->
		<dependency>
			<groupId>org.apache.struts</groupId>
			<artifactId>struts2-core</artifactId>
			<version>2.5.20</version>
		</dependency>

		<!-- https://mvnrepository.com/artifact/commons-logging/commons-logging -->
		<dependency>
			<groupId>commons-logging</groupId>
			<artifactId>commons-logging</artifactId>
			<version>1.2</version>
		</dependency>




		<!-- https://mvnrepository.com/artifact/commons-logging/commons-logging-api -->
		<dependency>
			<groupId>commons-logging</groupId>
			<artifactId>commons-logging-api</artifactId>
			<version>1.1</version>
		</dependency>



		<!-- https://mvnrepository.com/artifact/org.apache.struts/struts2-convention-plugin -->
		<dependency>
			<groupId>org.apache.struts</groupId>
			<artifactId>struts2-convention-plugin</artifactId>
			<version>2.5.20</version>
			<exclusions>
				<exclusion>
					<groupId>org.ow2.asm</groupId>
					<artifactId>asm-tree</artifactId>
				</exclusion>
				<exclusion>
					<groupId>org.ow2.asm</groupId>
					<artifactId>asm-commons</artifactId>
				</exclusion>
				<exclusion>
					<groupId>org.ow2.asm</groupId>
					<artifactId>asm</artifactId>
				</exclusion>
			</exclusions>
		</dependency>
        
        <!-- https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-core -->
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.11.2</version>
</dependency>


        
        
		<!-- https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-core -->
	

		<dependency>
			<groupId>org.ow2.asm</groupId>
			<artifactId>asm</artifactId>
			<version>7.1</version>
		</dependency>


		<!-- https://mvnrepository.com/artifact/org.ow2.asm/asm-tree -->
		<dependency>
			<groupId>org.ow2.asm</groupId>
			<artifactId>asm-tree</artifactId>
			<version>7.1</version>
		</dependency>


		<!-- https://mvnrepository.com/artifact/org.ow2.asm/asm-commons -->
		<dependency>
			<groupId>org.ow2.asm</groupId>
			<artifactId>asm-commons</artifactId>
			<version>7.1</version>
		</dependency>

	</dependencies>
</project>


来源：https://stackoverflow.com/questions/55219223/struts-2-convention-plugin-not-working-how-to-get-it-running

标签
java
struts2
struts2-convention-plugin
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