NoUniqueBeanDefinitionException和JSON乱码处理出现异常

Spring项目中的异常信息

NoUniqueBeanDefinitionException

org.springframework.beans.factory.NoUniqueBeanDefinitionException: 
No qualifying bean of type 'com.Person' available: expected single matching bean but found 2: person,com.Person#0

• 出现原因：

  Spring项目中出现了NoUniqueBeanDefinitionException异常，是不唯一bean错误，程序中找的是一个bean，自己设置两个bean，所以导致报错。

• 解决方法：

  指定给bean加个id，指定对应的备案，或者去掉重复的bean

SpringMVC项目中的JSON乱码处理出现的异常信息

Failed to introspect Class [org.springframework.http.converter.json.MappingJackson2HttpMessageConverter] from ClassLoader [ParallelWebappClassLoader

16-Jun-2020 09:48:58.999 严重 [RMI TCP Connection(3)-127.0.0.1] org.springframework.web.servlet.DispatcherServlet.initServletBean Context initialization failed
 org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter': Cannot create inner bean 'org.springframework.http.converter.json.MappingJackson2HttpMessageConverter#0' of type [org.springframework.http.converter.json.MappingJackson2HttpMessageConverter] while setting bean property 'messageConverters' with key [1]; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.http.converter.json.MappingJackson2HttpMessageConverter#0': Lookup method resolution failed; nested exception is java.lang.IllegalStateException: Failed to introspect Class [org.springframework.http.converter.json.MappingJackson2HttpMessageConverter] from ClassLoader [ParallelWebappClassLoader
  context: SpringMVCTest
  delegate: false
----------> Parent Classloader:
java.net.URLClassLoader@7bc1a03d
]
	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:389)
	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:127)
	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveManagedList(BeanDefinitionValueResolver.java:427)
	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:173)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1699)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1444)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517)
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:879)
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:878)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550)
	at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:702)
	at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:668)
	at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:716)
	at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:591)
	at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:530)
	at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:170)
	at javax.servlet.GenericServlet.init(GenericServlet.java:158)
	at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1183)
	at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1099)
	at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:989)
	at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4931)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5241)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)

• 出现原因：

  Jackson 依赖jar包没有全部引用，导致servlet容器初始化失败

• 解决方法：

  检查项目中是否引入下面三个jar包

  Jackson Databind 2.9.8.jar 包
  Jackson Annotations 2.9.8.jar 包
  Jackson-core 2.9.8.jar 包