java - Spring框架的XmlBeanDefinitionStoreException : The prefix "beans" for element "beans:bean" is not bound

Question

当我将请求传递给 RestController 时，出现以下错误。

org.springframework.beans.factory.xml.XmlBeanDefinitionStoreException: Line 22 in XML document from ServletContext resource [/WEB-INF/mvc-dispatcher-servlet.xml] is invalid; nested exception is org.xml.sax.SAXParseException; lineNumber: 22; columnNumber: 108; The prefix "beans" for element "beans:bean" is not bound.

org.xml.sax.SAXParseException; lineNumber: 22; columnNumber: 108; The prefix "beans" for element "beans:bean" is not bound.

这是 Controller :

@RestController
public class smsController {

    @RequestMapping(value = "/sendSMS", method = RequestMethod.POST)
    public void sendMessage(@RequestBody MessageBean msgBean) throws UnsupportedEncodingException {

        String numbers = msgBean.getNumbers();    
        String message = msgBean.getMessages();
    }
}

和dispatcher-servlet xml:

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       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/mvc
        http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">

    <context:component-scan base-package="com.spring.rest.controllers" />
    <mvc:annotation-driven />

    <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/views/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <beans:bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
        <beans:property name="messageConverters">
            <beans:list>
                <beans:ref bean="jsonMessageConverter"/>
            </beans:list>
        </beans:property>
    </beans:bean>
</beans>

类路径上的 jar :

jackson-annotations-2.3.2.jar
jackson-databind-2.3.2.jar
jackson-core-2.3.2.jar

我不确定是什么原因导致了这个问题。当我使用新的 jackson 2.7.4 jar 时，我收到另一个错误:

java.lang.NoClassDefFoundError: com/fasterxml/jackson/annotation/JsonTypeInfo$As

Answer 1

这个错误很明显，与 jackson 无关:

The prefix "beans" for element "beans:bean" is not bound.

它表示 beans 前缀或命名空间未定义。由于 beans 是默认命名空间:

xmlns="http://www.springframework.org/schema/beans"

因此，您应该从以下位置删除 beans: 前缀:

<beans:bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
    <beans:property name="messageConverters">
        <beans:list>
            <beans:ref bean="jsonMessageConverter"/>
        </beans:list>
    </beans:property>
</beans:bean>

最终结果如下:

<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
    <property name="messageConverters">
        <list>
            <ref bean="jsonMessageConverter"/>
        <list>
    </property>
</bean>

如果您打算通过此配置启用 JSON 转换，我应该说没有必要。由于对类路径存在适当的依赖关系，Spring MVC 将自动注册所需的 HttpMessageConverter 以进行 JSON 转换。 因此您可以删除该配置。

最后，您的 dispatcher-servlet.xml 将如下所示:

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       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/mvc
        http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">

    <context:component-scan base-package="com.spring.rest.controllers" />
    <mvc:annotation-driven />

    <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/views/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
</beans>

还有一句建议，如果您是 Spring 框架的新手，最好从 Spring Boot 开始.