方案一：利用Session防止表单重复提交
具体的做法：
1、获取用户填写用户名和密码的页面时向后台发送一次请求，这时后台会生成唯一的随机标识号，专业术语称为Token(令牌)。
2、将Token发送到客户端的Form表单中，在Form表单中使用隐藏域来存储这个Token，表单提交的时候连同这个Token一起提交到服务器端。
3、服务器端判断客户端提交上来的Token与服务器端生成的Token是否一致，如果不一致，那就是重复提交了，此时服务器端就可以不处理重复提交的表单。如果相同则处理表单提交，处理完后清除当前用户的Session域中存储的标识号。
看具体的范例：
1.创建FormServlet，用于生成Token(令牌)和跳转到form.jsp页面
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class FormServlet extends HttpServlet {
private static final long serialVersionUID = -884689940866074733L;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String token = UUID.randomUUID().toString() ;//创建令牌
System.out.println("在FormServlet中生成的token："+token);
request.getSession().setAttribute("token", token); //在服务器使用session保存token(令牌)
request.getRequestDispatcher("/form.jsp").forward(request, response);//跳转到form.jsp页面
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
2.在form.jsp中使用隐藏域来存储Token(令牌)
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>form表单</title>
</head>
<body>
<form action="${pageContext.request.contextPath}/servlet/DoFormServlet" method="post">
<%--使用隐藏域存储生成的token--%>
<%--
<input type="hidden" name="token" value="<%=session.getAttribute("token") %>">
--%>
<%--使用EL表达式取出存储在session中的token--%>
<input type="hidden" name="token" value="${token}"/>
用户名：<input type="text" name="username">
<input type="submit" value="提交">
</form>
</body>
</html>
3.DoFormServlet处理表单提交
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class DoFormServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
boolean b = isRepeatSubmit(request);//判断用户是否是重复提交
if(b==true){
System.out.println("请不要重复提交");
return;
}
request.getSession().removeAttribute("token");//移除session中的token
System.out.println("处理用户提交请求！！");
}
private boolean isRepeatSubmit(HttpServletRequest request) {
String client_token = request.getParameter("token");
//1、如果用户提交的表单数据中没有token，则用户是重复提交了表单
if(client_token==null){
return true;
}
//取出存储在Session中的token
String server_token = (String) request.getSession().getAttribute("token");
//2、如果当前用户的Session中不存在Token(令牌)，则用户是重复提交了表单
if(server_token==null){
return true;
}
//3、存储在Session中的Token(令牌)与表单提交的Token(令牌)不同，则用户是重复提交了表单
if(!client_token.equals(server_token)){
return true;
}
return false;
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
方案二：判断请求url和数据是否和上一次相同
推荐，非常简单，页面不需要任何传入，只需要在验证的controller方法上写上自定义注解即可
1.写好自定义注解
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 SameUrlData {
}
2.写好拦截器
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
import com.thinkgem.jeesite.common.mapper.JsonMapper;
public class SameUrlDataInterceptor 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();
SameUrlData annotation = method.getAnnotation(SameUrlData.class);
if (annotation != null) {
if(repeatDataValidator(request))//如果重复相同数据
return false;
else
return true;
}
return true;
} else {
return super.preHandle(request, response, handler);
}
}
public boolean repeatDataValidator(HttpServletRequest httpServletRequest)
{
String params=JsonMapper.toJsonString(httpServletRequest.getParameterMap());
String url=httpServletRequest.getRequestURI();
Map<String,String> map=new HashMap<String,String>();
map.put(url, params);
String nowUrlParams=map.toString();//
Object preUrlParams=httpServletRequest.getSession().getAttribute("repeatData");
if(preUrlParams==null)//如果上一个数据为null,表示还没有访问页面
{
httpServletRequest.getSession().setAttribute("repeatData", nowUrlParams);
return false;
}
else//否则，已经访问过页面
{
if(preUrlParams.toString().equals(nowUrlParams))//如果上次url+数据和本次url+数据相同，则表示城府添加数据
{
return true;
}
else//如果上次 url+数据 和本次url加数据不同，则不是重复提交
{
httpServletRequest.getSession().setAttribute("repeatData", nowUrlParams);
return false;
}
}
}
}
<mvc:interceptor>
<mvc:mapping path="
@Retention(RetentionPolicy.RUNTIME) // 在运行时可以获取
@Target(value = {ElementType.METHOD, ElementType.TYPE}) // 作用到类，方法，接口上等
public @interface PreventRepetitionAnnotation {
}
2、AOP代码
import java.lang.reflect.Method;
import java.util.UUID;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.reflect.MethodSignature;
import org.com.rlid.utils.json.JsonBuilder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.EnableAspectJAutoProxy;
import org.springframework.stereotype.Component;
import demo.zzp.app.aop.annotation.OperaterAnnotation;
import demo.zzp.app.redis.JedisUtils;
@Aspect
@Component
@EnableAspectJAutoProxy(proxyTargetClass=true)
public class PreventRepetitionAspect {
@Autowired
private JedisUtils jedisUtils;
private static final String PARAM_TOKEN = "token";
private static final String PARAM_TOKEN_FLAG = "tokenFlag";
@Around(value = "@annotation(demo.zzp.app.aop.annotation.PreventRepetitionAnnotation)")
public Object excute(ProceedingJoinPoint joinPoint) throws Throwable{
try {
Object result = null;
Object[] args = joinPoint.getArgs();
for(int i = 0;i < args.length;i++){
if(args[i] != null && args[i] instanceof HttpServletRequest){
HttpServletRequest request = (HttpServletRequest) args[i];//被调用的方法需要加上HttpServletRequest request这个参数
HttpSession session = request.getSession();
if(request.getMethod().equalsIgnoreCase("get")){
//方法为get
result = generate(joinPoint, request, session, PARAM_TOKEN_FLAG);
}else{
//方法为post
result = validation(joinPoint, request, session, PARAM_TOKEN_FLAG);
}
}
}
return result;
} catch (Exception e) {
e.printStackTrace();
return JsonBuilder.toJson(false, "操作失败！", "执行防止重复提交功能AOP失败，原因：" + e.getMessage());
}
}
public Object generate(ProceedingJoinPoint joinPoint, HttpServletRequest request, HttpSession session,String tokenFlag) throws Throwable {
String uuid = UUID.randomUUID().toString();
request.setAttribute(PARAM_TOKEN, uuid);
return joinPoint.proceed();
}
public Object validation(ProceedingJoinPoint joinPoint, HttpServletRequest request, HttpSession session,String tokenFlag) throws Throwable {
String requestFlag = request.getParameter(PARAM_TOKEN);
//redis加锁
boolean lock = jedisUtils.tryGetDistributedLock(tokenFlag + requestFlag, requestFlag, 60000);
if(lock){
//加锁成功
//执行方法
Object funcResult = joinPoint.proceed();
//方法执行完之后进行解锁
jedisUtils.releaseDistributedLock(tokenFlag + requestFlag, requestFlag);
return funcResult;
}else{
//锁已存在
return JsonBuilder.toJson(false, "不能重复提交！", null);
}
}
}
3、Controller代码
@RequestMapping(value = "/index",method = RequestMethod.GET)
@PreventRepetitionAnnotation
public String toIndex(HttpServletRequest request,Map<String, Object> map){
return "form";
}
@RequestMapping(value = "/add",method = RequestMethod.POST)
@ResponseBody
@PreventRepetitionAnnotation
public String add(HttpServletRequest request){
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
return JsonBuilder.toJson(true, "保存成功！",null);
}
第一次点击提交表单，判断到当前的token还没有上锁，即给该token上锁。如果连续点击提交，则提示不能重复提交，当上锁的那次操作执行完，redis释放了锁之后才能继续提交。
以上就是java后台防止表单重复提交方法详解的详细内容，更多关于java后台防止表单重复提交的资料请关注编程网其它相关文章！
