SpringMVC使用拦截器和过滤器详情

1.使用过滤器：场景：过滤乱码

web.xml文件中配置

   
    
    characterEncodingFilter  
    org.springframework.web.filter.CharacterEncodingFilter  
      
        encoding  
        UTF-8  
      
      
        forceEncoding  
        true  
      
    
    
    characterEncodingFilter  
    /*  
  

首先在***-servlet.xml中配置，注册拦截器

public class TestInterceptor implements HandlerInterceptor{

	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
			throws Exception {
		//使用场景：过滤字符编码
		request.setCharacterEncoding("utf-8");
		//使用场景：判断用户是否登陆，用户未登录返回登录页面
		if(request.getSession().getAttribute("user")==null) {
			request.getRequestDispatcher("/clients/login").forward(request, response);
			return false;
		}
		System.out.println("执行到此处preHandle");
		//返回值表示拦截到此处，是否继续执行
		//false表示停止执行，true表示继续执行
		return true;
	}

	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
			ModelAndView modelAndView) throws Exception {
		modelAndView.addObject("msg", "从postHandle获得的msg");
		System.out.println("执行到此处postHandle");
	}

	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
			throws Exception {
		System.out.println("执行到此处afterCompletion");
	}

}