token interceptor

package com.smartt.api.interceptor;

import java.lang.annotation.*;

@Target(ElementType.METHOD)

@Retention (RetentionPolicy.RUNTIME)

@Documented

public @interface Token {

boolean save() default false;

boolean remove() default false;

}

package com.smartt.api.interceptor;

import java.lang.reflect.Method;

import java.util.UUID;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.springframework.web.method.HandlerMethod;

import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

public class TokenInterceptor extends HandlerInterceptorAdapter {

@Override  
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {  
    if (handler instanceof HandlerMethod) {  
        HandlerMethod handlerMethod = (HandlerMethod) handler;  
        Method method = handlerMethod.getMethod();  
        Token annotation = method.getAnnotation(Token.class);  
        if (annotation != null) {  
            boolean needSaveSession = annotation.save();  
            if (needSaveSession) {  
                request.getSession(false).setAttribute("token", UUID.randomUUID().toString());  
            }  
            boolean needRemoveSession = annotation.remove();  
            if (needRemoveSession) {  
                if (isRepeatSubmit(request)) {  
                    return false;  
                }  
                request.getSession(false).removeAttribute("token");  
            }  
        }  
        return true;  
    } else {  
        return super.preHandle(request, response, handler);  
    }  
}  

private boolean isRepeatSubmit(HttpServletRequest request) {  
    String serverToken = (String) request.getSession(false).getAttribute("token");  
    if (serverToken == null) {  
        return true;  
    }  
    String clinetToken = request.getParameter("token");  
    if (clinetToken == null) {  
        return true;  
    }  
    if (!serverToken.equals(clinetToken)) {  
        return true;  
    }  
    return false;  
}  

}