springMVC 防止表单重复提交

原理：在新建页面中Session保存token随机码，当保存时验证，通过后删除，当再次点击保存时由于服务器端的Session中已经不存在了，所有无法验证通过。

新建注解：Token.java
package gov.saxmz.one.controller;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Token {

    boolean save() default false;

    boolean remove() default false;
}


新建拦截器：TokenInterceptor.java
package gov.saxmz.one.controller;
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;
    }
}
在Spring-MVC.xml中配置 ：

<!--拦截器配置-->
  <mvc:interceptors>
       <mvc:interceptor>
            <mvc:mapping path="/**"/>
            <bean class="gov.saxmz.one.controller.TokenInterceptor"/>
        </mvc:interceptor>
    </mvc:interceptors>

在相关方法中加入注解：

在需要生成token的controller上增加@Token(save=true)，而在需要检查重复提交的controller上添加@Token(remove=true)就可以了。

在jsp页面中加入 :
   <input type="hidden" name="token" value="${token}">