spring aop 拦截业务方法，实现权限控制示例

难点：aop类是普通的java类，session是无法注入的，那么在有状态的系统中如何获取用户相关信息呢，session是必经之路啊，获取session就变的很重要。思索很久没有办法，后来在网上看到了解决办法。

思路是：

i. syscontext  成员变量 request,session,response 

ii. filter 目的是给 syscontext 中的成员赋值 

iii.然后在aop中使用这个syscontext的值

要用好，需要理解  threadlocal和  和filter 执行顺序

1.aop获取request，response，session等

public class syscontext { 
  private static threadlocal<httpservletrequest> requestlocal=new threadlocal<httpservletrequest>(); 
  private static threadlocal<httpservletresponse> responselocal=new threadlocal<httpservletresponse>(); 
  
  public static httpservletrequest getrequest(){ 
   return requestlocalget(); 
  } 
  
  public static void setrequest(httpservletrequest request){ 
   requestlocalset(request); 
  } 
  
  public static httpservletresponse getresponse(){ 
   return responselocalget(); 
  } 
  
  public static void setresponse(httpservletresponse response){ 
   responselocalset(response); 
  } 
  
  public static httpsession getsession(){ 
   return (httpsession)(getrequest())getsession(); 
  } 
 } 

2.添加过滤器

public class getcontextfilter implements filter{ 
 
  @override 
  public void destroy() { 
   
  } 
 
  @override 
  public void dofilter(servletrequest request, servletresponse response, 
    filterchain chain) throws ioexception, servletexception { 
   syscontextsetrequest((httpservletrequest)request); 
   syscontextsetresponse((httpservletresponse)response); 
   chaindofilter(request, response); 
  } 
 
  @override 
  public void init(filterconfig config) throws servletexception { 
   
  } 
 
 } 
 

3.配置web.xml 

将这部分放置在最前面，这样可以过滤到所有的请求

<filter> 
  <filter-name>sessionfilter</filter-name> 
  <filter-class>comuneifiltergetcontextfilter</filter-class> 
 </filter> 
 
 <filter-mapping> 
  <filter-name>sessionfilter</filter-name> 
  <url-pattern>*</url-pattern> 
 </filter-mapping> 

4.spring aop before

从session中取出用户名，如果不存在，抛出异常跳转，将错误信息放到request中

@aspect 
 public class adminaspect { 
  actioncontext context = actioncontextgetcontext(); 
  httpservletrequest request; 
  httpservletresponse response; 
 
  @before("execution(* comuneiactionadminactiongetprivileges())") 
  public void adminprivilegecheck() 
    throws throwable { 
   httpsession session = syscontextgetsession(); 
   request = syscontextgetrequest(); 
   response = syscontextgetresponse(); 
   string username = ""; 
   
   try { 
    username = sessiongetattribute("username")tostring(); 
    if(username==null||usernameequals("")) 
     throw new exception("no privilege"); 
   } catch (exception ex) { 
    requestsetattribute("msg", "{\"res\":\"" + "无权限" + "\"}"); 
    try { 
     requestgetrequestdispatcher("/jsp/jsonjsp")forward( 
       request, response); 
    } catch (servletexception e) { 
     eprintstacktrace(); 
    } catch (ioexception e) { 
     eprintstacktrace(); 
    } 
   } 
  } 
 } 

5.applicationcontext.xml

<bean id="adminaspect" class="comuneiaopadminaspect"></bean> 

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。