web工程禁用HTTP中PUT/ELETE等请求，防止恶意访问

在web.xml最后加入如下节点
 <!--禁用PUT/DELETE请求  -->
<security-constraint>  
　　<web-resource-collection>  
	<url-pattern>/*</url-pattern>  			
	<http-method>PUT</http-method>  
	<http-method>DELETE</http-method>
　　</web-resource-collection>  
　　<auth-constraint>  
　　</auth-constraint>  
</security-constraint>