spring 版本升级到4.3.20.RELEASE与jackson的冲突

版本

记录spring 版本升级到4.3.20.RELEASE之后的一个小问题，升级后jackson和spring依赖如下：

• jackson 依赖

    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.1.3</version>
    </dependency>
  

• springmvc 依赖

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>4.3.20.RELEASE</version> 
    </dependency> 
  

启动异常

    Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter': Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter]: Constructor threw exception; nested exception is java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/util/DefaultIndenter
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1160)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1104)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:511)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:481)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:312)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:308)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:93)
    at com.baofoo.cgwfi.pro.start.StartByMain.main(StartByMain.java:18)
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter]: Constructor threw exception; nested exception is java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/util/DefaultIndenter
    at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:154)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:89)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1152)
    ... 13 more
Caused by: java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/util/DefaultIndenter
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.init(AbstractJackson2HttpMessageConverter.java:98)
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.<init>(AbstractJackson2HttpMessageConverter.java:91)
    at org.springframework.http.converter.json.MappingJackson2HttpMessageConverter.<init>(MappingJackson2HttpMessageConverter.java:66)
    at org.springframework.http.converter.json.MappingJackson2HttpMessageConverter.<init>(MappingJackson2HttpMessageConverter.java:57)
    at org.springframework.http.converter.support.AllEncompassingFormHttpMessageConverter.<init>(AllEncompassingFormHttpMessageConverter.java:66)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.<init>(RequestMappingHandlerAdapter.java:204)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:142)
    ... 15 more
Caused by: java.lang.ClassNotFoundException: com.fasterxml.jackson.core.util.DefaultIndenter
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    ... 26 more

异常原因

低版本的的jackson-core，比如说2.1.3，缺少com.fasterxml.jackson.core.util.DefaultIndenter类；

解决办法

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
	<artifactId>jackson-databind</artifactId>
    <version>2.8.3</version>
</dependency>

备注

应用中使用<mvc:annotation-driven />注解后会调用org.springframework.web.servlet.config.AnnotationDrivenBeanDefinitionParser来解析,这个类的作用
Responsible for:

• Registering a DefaultAnnotationHandlerMapping bean for mapping HTTP Servlet Requests to @Controller methods using @RequestMapping annotations.
• Registering a AnnotationMethodHandlerAdapter bean for invoking annotated @Controller methods. Will configure the HandlerAdapter’s webBindingInitializer property for centrally configuring @Controller DataBinder instances:
  Configures the conversionService if specified, otherwise defaults to a fresh ConversionService instance created by the default FormattingConversionServiceFactoryBean.
  Configures the validator if specified, otherwise defaults to a fresh Validator instance created by the default LocalValidatorFactoryBean if the JSR-303 API is present on the classpath.
  Configures standard HttpMessageConverters, including the Jaxb2RootElementHttpMessageConverter if JAXB2 is present on the classpath, and the MappingJacksonHttpMessageConverter if Jackson is present on the classpath.

在AnnotationMethodHandlerAdapter Bean中会配置多个messageConverters，如果classpath中有com.fasterxml.jackson.databind.ObjectMapper、com.fasterxml.jackson.dataformat.xml.XmlMapper类，会调用相关类，创建 messageConverters

private static final boolean jackson2Present = ClassUtils.isPresent("com.fasterxml.jackson.databind.ObjectMapper", AnnotationDrivenBeanDefinitionParser.class.getClassLoader()) && ClassUtils.isPresent("com.fasterxml.jackson.core.JsonGenerator", AnnotationDrivenBeanDefinitionParser.class.getClassLoader());

getMessageConverters中

        if (jackson2XmlPresent) {
            type = MappingJackson2XmlHttpMessageConverter.class;
            jacksonConverterDef = this.createConverterDefinition(type, source);
            jacksonFactoryDef = this.createObjectMapperFactoryDefinition(source);
            jacksonFactoryDef.getPropertyValues().add("createXmlMapper", true);
            jacksonConverterDef.getConstructorArgumentValues().addIndexedArgumentValue(0, jacksonFactoryDef);
            messageConverters.add(jacksonConverterDef);
        } else if (jaxb2Present) {
            messageConverters.add(this.createConverterDefinition(Jaxb2RootElementHttpMessageConverter.class, source));
        }

        if (jackson2Present) {
            type = MappingJackson2HttpMessageConverter.class;
            jacksonConverterDef = this.createConverterDefinition(type, source);
            jacksonFactoryDef = this.createObjectMapperFactoryDefinition(source);
            jacksonConverterDef.getConstructorArgumentValues().addIndexedArgumentValue(0, jacksonFactoryDef);
            messageConverters.add(jacksonConverterDef);
        } else if (gsonPresent) {
            messageConverters.add(this.createConverterDefinition(GsonHttpMessageConverter.class, source));
        }

参考

https://blog.youkuaiyun.com/fw0124/article/details/48280083