boot结合redis，防止重复提交

在Spring Boot中结合Redis来防止重复提交，通常的做法是利用Redis的原子性操作来实现。以下是一个简单的示例，展示如何使用Redis来防止用户在短时间内重复提交表单。

1. 添加依赖

首先，确保你的Spring Boot项目中已经添加了Spring Data Redis和Redis客户端的依赖。在pom.xml中添加如下依赖：

<dependencies>
    <!-- Spring Boot Redis starter -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-redis</artifactId>
    </dependency>
    <!-- Redis客户端 Lettuce -->
    <dependency>
        <groupId>io.lettuce.core</groupId>
        <artifactId>lettuce-core</artifactId>
    </dependency>
</dependencies>

2. 配置Redis

在application.properties或application.yml中配置Redis连接信息：

# application.properties
spring.redis.host=localhost
spring.redis.port=6379

3. 创建Redis配置类

创建一个配置类来配置Redis模板：

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.StringRedisSerializer;

@Configuration
public class RedisConfig {

    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {
        RedisTemplate<String, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(redisConnectionFactory);
        template.setKeySerializer(new StringRedisSerializer());
        template.setValueSerializer(new StringRedisSerializer());
        return template;
    }
}

4. 创建防止重复提交的服务

创建一个服务类，用于检查和设置Redis中的锁：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;

import java.time.Duration;
import java.util.concurrent.TimeUnit;

@Service
public class RedisService {

    @Autowired
    private RedisTemplate<String, Object> redisTemplate;

    public boolean trySetIfAbsent(String key, String value, long timeout, TimeUnit unit) {
        Boolean result = redisTemplate.opsForValue().setIfAbsent(key, value, timeout, unit);
        return result != null && result;
    }

    public void delete(String key) {
        redisTemplate.delete(key);
    }
}

5. 使用服务防止重复提交

在你的控制器或业务逻辑中使用这个服务来防止重复提交：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class SubmissionController {

    @Autowired
    private RedisService redisService;

    @PostMapping("/submit")
    public String submitForm(String userId, String data) {
        String key = "submit:" + userId;
        String value = "locked";
        long timeout = 5; // 5秒内不允许重复提交

        if (redisService.trySetIfAbsent(key, value, timeout, TimeUnit.SECONDS)) {
            // 处理提交逻辑
            return "提交成功";
        } else {
            return "请勿重复提交";
        }
    }
}