详解HandlerInterceptor处理器拦截器的用法

package org.springframework.web.servlet;  
public interface HandlerInterceptor {  
    boolean preHandle(  
            HttpServletRequest request, HttpServletResponse response,   
            Object handler)   
            throws Exception;  
    void postHandle(  
            HttpServletRequest request, HttpServletResponse response,   
            Object handler, ModelAndView modelAndView)   
            throws Exception;  
    void afterCompletion(  
            HttpServletRequest request, HttpServletResponse response,   
            Object handler, Exception ex)  
            throws Exception;  
}   

public abstract class HandlerInterceptorAdapter implements HandlerInterceptor {  
     //省略代码 此处所以三个回调方法都是空实现，preHandle返回true。  
}  

 <mvc:interceptors>
    <mvc:interceptor>
     <mvc:mapping path="/**" />
     <mvc:exclude-mapping path="/static/**" />
     <bean class="拦截器java代码路径" />
    </mvc:interceptor>
 </mvc:interceptors>

package cn.wmyskxz.interceptor;
import cn.wmyskxz.pojo.User;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.util.Arrays;
/**
 * 登录拦截器：
 */
public class LoginInterceptor extends HandlerInterceptorAdapter {
	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
		HttpSession session = request.getSession();
		String[] noNeedAuthPage = new String[]{
				"/home",
				"/searchProduct",
				"/sortProduct",
				"/showProduct",
				"/loginPage",
				"/login",
				"/registerPage",
				"/register",
				"/registerSuccessPage",
				"/test",
				"/checkLogin",
				"/admin"
		};
		String uri = request.getRequestURI();
		if (!Arrays.asList(noNeedAuthPage).contains(uri)) {
			User user = (User) session.getAttribute("user");
			if (null == user) {
				response.sendRedirect("/loginPage");
				return false;
			}
		}
		return true;
	}
	@Override
	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
	}
	@Override
	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
		super.afterCompletion(request, response, handler, ex);
	}
}