使用redis锁防止表单重复提交

模拟表单重复提交

使用Swagger调用接口

通过界面添加学生

分析

入库时的验重逻辑是入库前先去数据库查询一次，没有发现该条数据则入库，这样的操作并不是原子性的，会导致如果有两条一样的数据同时过来，同一时间查询数据库的话，会发现并没有这条数据，这样就会将这两条一样的数据同时入库。因此，我们需要在入库前加一把锁，使得同时过来的同样的数据只有一条能去进行查询数据库验重这步操作。

使用redis分布式锁防止数据重复入库

    /**
     * 学生保存
     * @param stu
     * @return
     */
    @Log("保存学生")
    @ApiOperation(value = "学生信息保存", notes = "将输入的学生信息保存到数据库")
    @PostMapping(value = "/save", produces = MediaType.APPLICATION_JSON_VALUE)
    @ResponseBody
    public ActionResult saveStudent(StudentDO stu){
        ActionResult result = new ActionResult();

        if(stu.getSno()==null){
            String lockKey = "student:phone:"+stu.getPhone();
            RLock lock = redissonClient.getLock(lockKey);
            boolean res = false;
            try {
                //获取锁等待超时时间为5s,锁租期为60s
                res = lock.tryLock(5, 60, TimeUnit.SECONDS);
            } catch (Exception e) {
                logger.error(e.getMessage(), e);
            }
            if (!res) {
                logger.info("获取锁超时 res: {}", res);
                result.setStatus(-2);
                result.setMsg("该学生正在新增中，请稍后再试...");
                return result;
            }

            try {
                List<StudentDO> list = studentDOMapper.selectByPhone(stu.getPhone());
                if(list!=null&&list.size()>0){
                    result = ActionResult.build(-1, "手机号码重复，添加失败");
                    return result;
                }
                studentDOMapper.insert(stu);
            } finally {
                //超过leaseTime锁自动释放，导致unlock方法失效
                try {
                    if (lock.isHeldByCurrentThread() && lock.isLocked()) {
                        lock.unlock();
                        logger.info("释放锁");
                    }
                } catch (Exception e) {
                    logger.error(e.getMessage(), e);
                }
            }

        } else {
            List<StudentDO> list = studentDOMapper.selectByPhoneAndSno(stu.getPhone(), stu.getSno());
            if(list!=null&&list.size()>0){
                result = ActionResult.build(-1, "手机号码重复，修改失败");
                return result;
            }
            studentDOMapper.updateByPrimaryKey(stu);
        }
        result = ActionResult.ok(studentDOMapper.selectByPrimaryKey(stu.getSno()));
        return result;
    }

再次模拟表单重复提交

模拟表单重复提交的脚本

package com.yangzc.studentboot;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;

/**
 * @Author: yangzc
 * @Description:
 * @Date: Created on 8:04 2020/6/9
 * @Modified By:
 */
public class StudentTest {
    public static void main(String[] args) {
        //创建可关闭的客户端工具
        CloseableHttpClient c1 = HttpClients.createDefault();
        CloseableHttpClient c2 = HttpClients.createDefault();

        HttpPost r1 = new HttpPost("http://192.168.18.107:8080/stu/list/save");
        HttpPost r2 = new HttpPost("http://192.168.18.107:8080/stu/list/save");

        String data = "sno=&sname=%E5%BC%A0%E4%B8%89&gender=1&birth=2020-06-08&phone=17721038957&photoUrl=%2Fimg%2Fdefault.png";

        StringEntity requestEntity = new StringEntity(data,"utf-8");

        r1.addHeader("Content-type","application/x-www-form-urlencoded");
        r1.addHeader("Cookie","JSESSIONID=5010b0b0-1ee1-4448-9edf-b3abe3cd61b8");
        r1.setEntity(requestEntity);

        r2.addHeader("Content-type","application/x-www-form-urlencoded");
        r2.addHeader("Cookie","JSESSIONID=5010b0b0-1ee1-4448-9edf-b3abe3cd61b8");
        r2.setEntity(requestEntity);

        Thread t1 = new MyThread(c1,r1);
        Thread t2 = new MyThread(c2,r2);

        t1.start();
        t2.start();
        //c1.close();
        //c2.close();
        //System.out.println("Hello World!");
    }
}

package com.yangzc.studentboot;
import java.io.IOException;

import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.util.EntityUtils;
/**
 * @Author: yangzc
 * @Description:
 * @Date: Created on 8:08 2020/6/9
 * @Modified By:
 */
public class MyThread extends Thread {
    private CloseableHttpClient client;
    private HttpPost request;

    public MyThread(CloseableHttpClient client, HttpPost request) {
        this.client = client;
        this.request = request;
    }

    public void run(){
        try {
            HttpResponse response = client.execute(request);
            String text = EntityUtils.toString(response.getEntity());
            System.out.println(Thread.currentThread().getName()+": "+text);
            client.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

项目开源地址

https://github.com/yangzc23/studentboot

参考资料
[01] 使用Session防止表单重复提交
[02] JavaWeb防止表单重复提交的几种方式
[03] Redisson基本用法
[04] redis客户端redisson实战
[05] HttpClient 4 使用POST方式提交普通表单数据的例子
[06] Redis分布式锁的实现原理
[07] 使用Redis分布式锁处理并发，解决超卖问题
[08] Redission分布式锁
[09] Bootstrap表单
[10] git 放弃本地修改，强制拉取更新
[11] Java使用Redis实现分布式锁来防止重复提交问题
[12] 利用redis分布式锁来防止数据重复入库
[13] BootStrap Validator 版本差异问题导致的submitHandler失效问题的解决方法
[14] BootstrapValidator使用教程
[15] bootstrapvalidator实现校验、校验清除重置
[16] bootstrapvalidator校验、校验清除重置

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