Spring's namespace handler for a namespace not found

1. The Problem

This article will discuss the most common configuration problem in Spring - the namespace handler for one of Spring's namespaces was not found. In most cases it is due to a particular Spring jar not being configured on the classpath, let's list most of the possible missing configurations and resulting exceptions.





2. http://www.springframework.org/schema/security The

security namespace is probably the most widespread problem encountered in practice so far:


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<?xml version="1.0" encoding="UTF-8" ?>
<beans:beans xmlns="http://www.springframework.org/schema/security"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:beans="http ://www.springframework.org/schema/beans"
    xsi:schemaLocation="
        http://www.springframework.org/schema/security
        http://www.springframework.org/schema/security/spring-security-3.1 .xsd
        http://www.springframework.
        http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">

</beans:beans> results in

the following exception: org.springframework.beans.factory.parsing.BeanDefinitionParsingException: Configuration problem: Unable to locate Spring NamespaceHandler for XML schema namespace [http://www.springframework.org/schema/security] Offending resource: class path resource [securityConfig.xml] The solution is very simple - configure the jar of spring-security-config In the classpath (eg: maven's pom.xml): <dependency>    <groupId>org.springframework.security</groupId>    <artifactId>spring-security-config</artifactId>    <version>3.1.4.RELEASE</ version> </dependency>

















Configure the correct namespace handler - in this case the SecurityNamespaceHandler on the classpath will resolve elements in the security namespace.



3. http://www.springframework.org/schema/aop

occurs when the aop namespace is used, and the corresponding spring jar is not configured on the classpath:


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<beans
    xmlns="http://www.springframework. org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xsi:schemaLocation= "
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
        http://www.springframework.org/schema/aop
        http: //www.springframework.org/schema/aop/spring-aop-3.2.xsd">

</beans>



Causes the following exception:

org.springframework.beans.factory.parsing.BeanDefinitionParsingException:
Configuration problem:
Unable to locate Spring NamespaceHandler for XML schema namespace
[http://www.springframework.org/schema/aop]
Offending resource: ServletContext resource [/ WEB-INF/webConfig.xml] The

solution is similar to problem 2, just configure the jar of spring-aop under calsspath:

<dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-aop</artifactId>
   <version>3.2.5.RELEASE</version> <
/dependency>



4. http://www.springframework.org/schema/tx using transaction namespaces

- a small but very useful namespace configuration: beans     xmlns="http://www.springframework. org/schema/beans"





    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx-3.2.xsd">

</beans>

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导致以下异常：

org.springframework.beans.factory.parsing.BeanDefinitionParsingException:
Configuration problem:
Unable to locate Spring NamespaceHandler for XML schema namespace
[http://www.springframework.org/schema/tx]
Offending resource: class path resource [daoConfig.xml]

The solution is to configure the jar of the transaction to the classpath:

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-tx</artifactId>
    <version>3.2 .5.RELEASE</version>
</dependency>



5. http://www.springframework.org/schema/mvc

Below is spring's mvc namespace


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<beans
    xmlns="http://www.springframework.org /schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:tx="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring- mvc-3.2.xsd">

</beans>

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results in the following exception:

org.springframework.beans.factory.parsing.BeanDefinitionParsingException:
Configuration problem:
Unable to locate Spring NamespaceHandler for XML schema namespace
[http://www.springframework. org/schema/mvc]
Offending resource: class path resource [webConfig.xml]

encountered this exception because the spring mvc jar was not configured in the classpath:

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>3.2.5.RELEASE</version>
</dependency>



6. Conclusion

Finally , if you are using Eclipse to manage the web server and deployment, make sure that the assembly part of the deployment project is configured correctly - ie Maven dependencies, is actually included in the class classpath at deployment time.