首先，我很抱歉再次提出这个问题。上次是 3 个月前，我找到了一种权宜之计，当时可以用于概念验证。不幸的是，我真的需要让它正常工作完整
作为我当前项目的一部分，当请求发送到 Spring 服务器或从 Spring 服务器发送请求时，我需要能够自动将对象序列化为 JSON 和 JSON。我被告知要使用 jackson 来做这件事。问题是，每次我将 Jackson 添加到 POM 时，它都会构建，但 servlet 在找不到 com.fasterxml.jackson.core.JsonProcessingException 时会抛出 java.lang.NoClassDefError。不过我已经检查过了，JsonProcessingException 是 WAR 中应该出现的地方。
我怀疑这导致 Spring 尝试为 servlet Autowiring Jackson 解析器，但它无法找到所有依赖项。我不知道为什么会这样，因为它们应该被 Maven 正确地引入。
我的 pom.xml 包含概括的公司具体信息:
<?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>
<parent>
<groupId>com.company.department</groupId>
<artifactId>project</artifactId>
<version>1.0-SNAPSHOT</version>
</parent>
<artifactId>project-restservice</artifactId>
<packaging>war</packaging>
<name>projectMaven Restservice</name>
<dependencies>
<dependency>
<groupId>${project.groupId}</groupId>
<artifactId>project-common</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>${project.groupId}</groupId>
<artifactId>project-processor</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>${project.groupId}</groupId>
<artifactId>project-ui-service</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>com.qualcomm.qes.logging</groupId>
<artifactId>project-logger</artifactId>
<scope>compile</scope>
<exclusions>
<exclusion>
<artifactId>org.slf4j</artifactId>
<groupId>com.springsource.slf4j.api</groupId>
</exclusion>
<exclusion>
<artifactId>org.slf4j</artifactId>
<groupId>com.springsource.slf4j.log4j</groupId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>com.qualcomm.qes.sso.downstream</groupId>
<artifactId>sso-downstream-auth</artifactId>
<exclusions>
<exclusion>
<artifactId>bcprov-jdk15on</artifactId>
<groupId>bouncycastle</groupId>
</exclusion>
</exclusions>
</dependency>
<!-- SpringSource -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>org.springframework.web.servlet</artifactId>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>org.springframework.web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>org.springframework.core</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>org.springframework.beans</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>org.springframework.context</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>org.springframework.oxm</artifactId>
<exclusions>
<exclusion>
<artifactId>xml-apis</artifactId>
<groupId>xml-apis</groupId>
</exclusion>
</exclusions>
</dependency>
<!-- Other -->
<!-- Jackson JSON Mapper -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.5.1</version>
</dependency>
<!-- JMS -->
<dependency>
<groupId>javax.transaction</groupId>
<artifactId>com.springsource.javax.transaction</artifactId>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>com.springsource.javax.servlet</artifactId>
<scope>provided</scope>
</dependency>
<!-- TIBCO JMS -->
<dependency>
<groupId>com.tibco</groupId>
<artifactId>tibjms</artifactId>
</dependency>
<!-- TESTS -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>org.springframework.test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<finalName>${project.artifactId}-${project.version}</finalName>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<!-- TODO: wants version number -->
<configuration>
<webResources>
<resource>
<directory>${basedir}/src/main/webapp/WEB-INF</directory>
<filtering>true</filtering>
<targetPath>WEB-INF</targetPath>
<includes>
<include>**/jboss-classloading.xml</include>
</includes>
</resource>
</webResources>
</configuration>
</plugin>
</plugins>
</build>
<profiles>
<profile>
<id>deploy-war</id>
<build>
<plugins>
<plugin>
<artifactId>maven-antrun-plugin</artifactId>
<executions>
<execution>
<id>deploy-to-server</id>
<phase>install</phase>
<goals>
<goal>run</goal>
</goals>
<configuration>
<tasks>
<copy file="${project.build.directory}/${project.artifactId}-${project.version}.war" todir="${project.jboss.home}/standalone/deployments/project.ear/"></copy>
</tasks>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</profile>
</profiles>
</project>
我的 web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version="2.4">
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/project-restservice-servlet.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>project-restservice</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>project-restservice</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
我的 servlet 上下文:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:oxm="http://www.springframework.org/schema/oxm"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/oxm http://www.springframework.org/schema/oxm/spring-oxm-3.0.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">
<context:component-scan base-package="com.company.department.project.controller" />
<mvc:annotation-driven/>
<mvc:resources mapping="/html/**" location="/static/html/" />
<mvc:resources mapping="/js/**" location="/static/js/" />
<mvc:resources mapping="/css/**" location="/static/css/" />
<mvc:resources mapping="/images/**" location="/static/images/" />
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix">
<value>/WEB-INF/pages/</value>
</property>
<property name="suffix">
<value>.jsp</value>
</property>
</bean>
我的 Controller :
@Controller
public class RestServiceWebController extends BaseRestServiceController
{
@Autowired
private SampletableService sampletableService;
@RequestMapping(value="/sample", method=RequestMethod.GET)
public String customerPortal(ModelMap model)
{
return "sample";
}
@RequestMapping(value="/testService", method=RequestMethod.GET)
public @ResponseBody Map<String, String> testMethod()
{
logger.info("In testService");
Map<String,String> testResponse = new HashMap<String, String>();
testResponse.put("1", "2");
testResponse.put("3", "4");
testResponse.put("5", "6");
testResponse.put("7", "8");
testResponse.put("9", "0");
return testResponse;
}
}
日志摘录:
2015-02-19 09:35:56,638 ERROR [org.springframework.web.context.ContextLoader] (ServerService Thread Pool -- 54) Context initialization failed: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#0': Initialization of bean failed; nested exception is java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/JsonProcessingException
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:529)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:626)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:389)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:294)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112)
at org.apache.catalina.core.StandardContext.contextListenerStart(StandardContext.java:3339)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:3777)
at org.jboss.as.web.deployment.WebDeploymentService.doStart(WebDeploymentService.java:156)
at org.jboss.as.web.deployment.WebDeploymentService.access$000(WebDeploymentService.java:60)
at org.jboss.as.web.deployment.WebDeploymentService$1.run(WebDeploymentService.java:93)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:744)
at org.jboss.threads.JBossThread.run(JBossThread.java:122)
Caused by: java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/JsonProcessingException
at java.lang.Class.getDeclaredConstructors0(Native Method)
at java.lang.Class.privateGetDeclaredConstructors(Class.java:2493)
at java.lang.Class.getDeclaredConstructors(Class.java:1901)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.determineCandidateConstructors(AutowiredAnnotationBeanPostProcessor.java:230)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.determineConstructorsFromBeanPostProcessors(AbstractAutowireCapableBeanFactory.java:972)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:945)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:487)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:271)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:126)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveManagedList(BeanDefinitionValueResolver.java:353)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:154)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1387)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1128)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
... 22 more
如果您需要更多信息，请告诉我。
编辑:
因此，进行了一些探测并遵循类似的线索，我设法将其追踪到 Autowiring Jackson bean 的标签。删除它并手动添加转换器，如下所示:
<bean id="jsonMessageConverter" class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter" />
导致同样的错误。所以至少现在我知道是什么原因造成的，但是依赖项存在，所以我不确定为什么它说找不到它们。
最佳答案
您错过了Jackson-core.jar。将其添加到您的 pom
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.5.1</version>
</dependency>
关于java - 将 Jackson 添加到 POM 会导致 JsonProcessingException 出现 NoClassDefError，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/28610551/