Question

我遇到了一个问题，但我无法弄清楚这个问题的原因，因为错误相当普遍。

java.lang.NoClassDefFoundError：无法初始化类org.springframework.web.util.NestedServletException at org.springframework.web.servlet.FrameworkServlet.processRequest（FrameworkServlet.java:980）在 org.springframework.web.servlet.FrameworkServlet.doGet（FrameworkServlet.java:859）在javax.servlet.http.HttpServlet.service（HttpServlet.java:687）at org.springframework.web.servlet.FrameworkServlet.service（FrameworkServlet.java:844）在javax.servlet.http.HttpServlet.service（HttpServlet.java:790）at org.eclipse.jetty.servlet.ServletHolder.handle（ServletHolder.java:845）在 org.eclipse.jetty.servlet.ServletHandler.doHandle（ServletHandler.java:583）在 org.eclipse.jetty.server.handler.ContextHandler.doHandle（ContextHandler.java:1160）在 org.eclipse.jetty.servlet.ServletHandler.doScope（ServletHandler.java:511）在 org.eclipse.jetty.server.handler.ContextHandler.doScope（ContextHandler.java:1092）在 org.eclipse.jetty.server.handler.ScopedHandler.handle（ScopedHandler.java:141）在 org.eclipse.jetty.server.handler.HandlerWrapper.handle（HandlerWrapper.java:134）在org.eclipse.jetty.server.Server.handle（Server.java:518）at org.eclipse.jetty.server.HttpChannel.handle（HttpChannel.java:308）at at org.eclipse.jetty.server.HttpConnection.onFillable（HttpConnection.java:244）在 org.eclipse.jetty.io.AbstractConnection $ ReadCallback.succeeded（AbstractConnection.java:273）在org.eclipse.jetty.io.FillInterest.fillable（FillInterest.java:95）在 org.eclipse.jetty.io.SelectChannelEndPoint $ 2.run（SelectChannelEndPoint.java:93）在 org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.produceAndRun（ExecuteProduceConsume.java:246）在 org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.run（ExecuteProduceConsume.java:156）在 org.eclipse.jetty.util.thread.QueuedThreadPool.runJob（QueuedThreadPool.java:654）在 org.eclipse.jetty.util.thread.QueuedThreadPool $ 3.run（QueuedThreadPool.java:572）在java.lang.Thread.run（Thread.java:745）

这是我的项目结构：

Project Structure

这是一个非常简单的项目，我将Embedded Jetty与SpringMVC一起使用。

这是pom.xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<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>com.biendltb</groupId>
<artifactId>com.biendltb.world_map</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>

<name>com.biendltb.world_map</name>

<properties>
    <endorsed.dir>${project.build.directory}/endorsed</endorsed.dir>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <jetty.version>9.3.8.v20160314</jetty.version>
    <spring.version>4.2.5.RELEASE</spring.version>
    <servlet.version>2.5</servlet.version>
</properties>

<dependencies>
    <dependency>
        <groupId>javax</groupId>
        <artifactId>javaee-web-api</artifactId>
        <version>7.0</version>
        <scope>provided</scope>
    </dependency>

    <!-- SPRING DEPENDENCY -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>${spring.version}</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-aop</artifactId>
        <version>${spring.version}</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>${spring.version}</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
        <version>${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-beans</artifactId>
        <version>4.2.5.RELEASE</version>
    </dependency>


    <!-- JETTY DEPENDENCY -->
    <dependency>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-server</artifactId>
        <version>${jetty.version}</version>
    </dependency>
    <dependency>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-servlet</artifactId>
        <version>${jetty.version}</version>
    </dependency>
    <dependency>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-webapp</artifactId>
        <version>${jetty.version}</version>
    </dependency>

    <!-- SERVLET DEPENDENCY -->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>${servlet.version}</version>
    </dependency>

    <!-- COMMON LOGGING DEPENDENCY -->
    <dependency>
        <groupId>commons-logging</groupId>
        <artifactId>commons-logging</artifactId>
        <version>1.1.3</version>
    </dependency>
</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.1</version>
            <configuration>
                <source>1.7</source>
                <target>1.7</target>
                <compilerArguments>
                    <endorseddirs>${endorsed.dir}</endorseddirs>
                </compilerArguments>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-dependency-plugin</artifactId>
            <version>2.6</version>
            <executions>
                <execution>
                    <phase>validate</phase>
                    <goals>
                        <goal>copy</goal>
                    </goals>
                    <configuration>
                        <outputDirectory>${endorsed.dir}</outputDirectory>
                        <silent>true</silent>
                        <artifactItems>
                            <artifactItem>
                                <groupId>javax</groupId>
                                <artifactId>javaee-endorsed-api</artifactId>
                                <version>7.0</version>
                                <type>jar</type>
                            </artifactItem>
                        </artifactItems>
                    </configuration>
                </execution>
            </executions>
        </plugin>
        <plugin>
            <groupId>org.eclipse.jetty</groupId>
            <artifactId>jetty-maven-plugin</artifactId>
            <version>9.3.7.v20160115</version>
        </plugin>
        <plugin>
            <artifactId>maven-war-plugin</artifactId>
            <version>2.4</version>
            <configuration>
                <warSourceDirectory>WebContent</warSourceDirectory>
                <failOnMissingWebXml>false</failOnMissingWebXml>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-shade-plugin</artifactId>
            <version>2.4.3</version>
            <executions>
                <execution>
                    <phase>package</phase>
                    <goals>
                        <goal>shade</goal>
                    </goals>
                    <configuration>
                        <createDependencyReducedPom>false</createDependencyReducedPom>
                        <transformers>
                            <transformer
                                implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                <mainClass>com.biendltb.main_server.TripMapServer</mainClass>
                            </transformer>
                        </transformers>
                        <filters>
                            <filter>
                                <artifact>*:*</artifact>
                                <excludes>
                                    <exclude>META-INF/*.SF</exclude>
                                    <exclude>META-INF/*.DSA</exclude>
                                    <exclude>META-INF/*.RSA</exclude>
                                </excludes>
                            </filter>
                        </filters>
                    </configuration>
                </execution>
            </executions>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-resources-plugin</artifactId>
            <version>2.7</version>
            <dependencies>
                <dependency>
                    <groupId>org.apache.maven.shared</groupId>
                    <artifactId>maven-filtering</artifactId>
                    <version>1.3</version>
                </dependency>
            </dependencies>
        </plugin>
    </plugins>
    <resources>
        <resource>
            <targetPath>webapp</targetPath>
            <directory>src/main/webapp</directory>
        </resource>
        <resource>
            <directory>src/main/resources</directory>
        </resource>
    </resources>
</build>

这是main类：

public class TripMapServer {

    private static final int DEFAULT_PORT = 8080;
    private static final String CONTEXT_PATH = "/";
    private static final String MAPPING_URL = "/*";
    private static final String CONFIG_LOCATION = "com.biendltb.config";
    private static final String DEFAULT_PROFILE = "dev";

    public static void main(String[] args) throws Exception {
        new TripMapServer().startJetty(getPortFromArgs(args));
    }

    private static int getPortFromArgs(String[] args) {
        if (args.length > 0) {
            try {
                return Integer.valueOf(args[0]);
            } catch (NumberFormatException ignore) {
            }
        }
        return DEFAULT_PORT;
    }

    private void startJetty(int port) throws Exception {
        Server server = new Server(port);
        server.setHandler(getServletContextHandler(getContext()));
        server.start();
        server.join();
    }

    private static ServletContextHandler getServletContextHandler(WebApplicationContext context) throws IOException {
        ServletContextHandler contextHandler = new ServletContextHandler();
        contextHandler.setErrorHandler(null);
        contextHandler.setContextPath(CONTEXT_PATH);
        contextHandler.addServlet(new ServletHolder("default", new DispatcherServlet(context)), MAPPING_URL);
        contextHandler.addEventListener(new ContextLoaderListener(context));
        contextHandler.setResourceBase(new ClassPathResource("webapp").getURI().toString());
        return contextHandler;
    }

    private static WebApplicationContext getContext() {
        AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
        context.setConfigLocation(CONFIG_LOCATION);
        context.getEnvironment().setDefaultProfiles(DEFAULT_PROFILE);
        return context;
    }
}

这是类WebConfig.java而不是.xml文件：

@Configuration
@EnableWebMvc
@Import({DefaultConfig.class})
@ComponentScan(basePackages = {"com.biendltb.controller"})
public class WebConfig extends WebMvcConfigurerAdapter{
    private static final Charset UTF8 = Charset.forName("UTF-8");

    @Autowired
    public Environment env;

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        converters.add(stringConverter());
    }

    private StringHttpMessageConverter stringConverter() {
        StringHttpMessageConverter stringConverter = new StringHttpMessageConverter();
        stringConverter.setSupportedMediaTypes(Arrays.asList(new MediaType("text", "plain", UTF8)));
        return stringConverter;
    }

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/assets/**").addResourceLocations("classpath:/src/main/resources/").setCachePeriod(Integer.MAX_VALUE);
        registry.addResourceHandler("/js/**").addResourceLocations("/js/").setCachePeriod(Integer.MAX_VALUE);
        registry.addResourceHandler("/css/**").addResourceLocations("/css/").setCachePeriod(Integer.MAX_VALUE);
        registry.addResourceHandler("/img/**").addResourceLocations("/img/").setCachePeriod(Integer.MAX_VALUE);
    }

    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

    @Bean
    public InternalResourceViewResolver getInternalResourceViewResolver() {
        InternalResourceViewResolver resolver = new InternalResourceViewResolver();
        resolver.setPrefix("/src/main/resources/pages/");
        resolver.setSuffix(".jsp");
        return resolver;
    }
}

请帮助找出原因或如何追踪该错误。

非常感谢！

Answer 1

NoClassDefFoundError通常意味着您在运行时丢失了一个jar文件，但并非总是如此，在您的情况下也不如此。类加载器的其他错误也可能导致它。

我在org.springframework.web.util.NestedServletException上遇到了同样的错误。我在调试器中运行了Jetty，并在org.springframework.web.servlet.FrameworkServlet试图构造NestedServletException的地方设置了一个断点，因此我可以看到它试图嵌套的异常。

事实证明这是一个StackOverflowError，并且由于JVM的堆栈帧不足，类加载器无法加载NestedServletException类。 Jetty ServletHolder正在调用Spring DispatcherServlet，然后将其转发回ServletHolder，从而使其再次调用DispatcherServlet。

Answer 2

您在运行时缺少一个类。调试启动并在NoClassDefFoundError上设置异常断点。比你看到哪个类无法找到。在IDE或Web中搜索该类，以找出您缺少的依赖项。

Answer 3

我建议您清除.m2文件夹，可能会发生某些jar文件在下载过程中损坏。

请评论，如果它没有帮助你！

java.lang.NoClassDefFoundError：无法初始化类org.springframework.web.util.NestedServletException

3 个答案: