SpringBoot+Redis 基本操作，实现排行榜功能，javasql 优化面试题

<artifactId>guava</artifactId>

<version>27.0.1-jre</version>

</dependency>

</dependencies>

配置 application.yml

spring:

redis:

database: 0

host: localhost

port: 6379

password: root

pool:

max-active: 8

max-wait: -1

max-idle: 8

min-idle: 0

timeout: 5000

server:

port: 8081

注入 RedisTemplate，还要有初始化 RedisConnectionFactory

package com.rosam.config;

import com.fasterxml.jackson.annotation.JsonAutoDetect;

import com.fasterxml.jackson.annotation.PropertyAccessor;

import com.fasterxml.jackson.databind.ObjectMapper;

import org.springframework.beans.factory.annotation.Autowired;

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.Jackson2JsonRedisSerializer;

import org.springframework.data.redis.serializer.JdkSerializationRedisSerializer;

import org.springframework.data.redis.serializer.StringRedisSerializer;

/**

• 自己的 redisTemplate

• @author Song.aw

• @create 2017-12-07 9:37

**/

@Configuration

public class RedisConfig{

@Autowired

RedisConnectionFactory redisConnectionFactory;

@Bean

public RedisTemplate<String, Object> functionDomainRedisTemplate() {

RedisTemplate<String, Object> redisTemplate = new RedisTemplate<String, Object>();

initDomainRedisTemplate(redisTemplate, redisConnectionFactory);

return redisTemplate;

}

private void initDomainRedisTemplate(RedisTemplate<String, Object> redisTemplate, RedisConnectionFactory factory) {

redisTemplate.setKeySerializer(new StringRedisSerializer());

redisTemplate.setHashKeySerializer(new StringRedisSerializer());

redisTemplate.setHashValueSerializer(new JdkSerializationRedisSerializer());

redisTemplate.setValueSerializer(new JdkSerializationRedisSerializer());

redisTemplate.setConnectionFactory(factory);

}

}

在 Controller 中的使用

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package com.rosam.controller;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.data.redis.core.RedisTemplate;

import org.springframework.data.redis.core.ZSetOperations;

import org.springframework.data.redis.support.atomic.RedisAtomicLong;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.*;

import java.util.Map;

import java.util.Set;

import java.util.concurrent.TimeUnit;

@Controller

@RequestMapping("/user")

public class UserController {

@Autowired

private RedisTemplate redisTemplate;

/**

• 登录后保存用户名为 userName,value 为 password

• @param userName

• @param password

• @return

*/

@GetMapping("/login")

@ResponseBody

public String login(@RequestParam("userName")String userName, @RequestParam("password")String password){

redisTemplate.opsForValue().set(userName, password);

redisTemplate.expire(userName,10,TimeUnit.SECONDS);

return "success";

}

/**

• 原子自增，设置过期时间

• @param params

• @return

*/

@RequestMapping(value = "/incrementScore", method = RequestMethod.POST)

@ResponseBody

public String incrementScore(@RequestBody Map<String, Object> params) {

String key = params.get("key").toString();

Long value =(Long) redisTemplate.opsForValue().get(key);

RedisAtomicLong entityIdCounter = new RedisAtomicLong(key, redisTemplate.getConnectionFactory());

entityIdCounter.expire(3, TimeUnit.SECONDS);//过期时间为 3 秒

Long increment = entityIdCounter.getAndIncrement();

redisTemplate.opsForValue().set(key,increment+value);

return "success";

}

/**

• 实现排序，热度，积分榜等功能，更多方法可以可以搜索 zSetOperations

• @return

*/

@GetMapping(value = "rankScore")

@ResponseBody

public String rank(){

ZSetOperations zSetOperations = redisTemplate.opsForZSet();

zSetOperations.add("score","one",1);

zSetOperations.add("score","four",4);

zSetOperations.add("score","three",110);

zSetOperations.add("score","five",5);

zSetOperations.add("score","six",6);

//从子集中找到 Smin<=score<=Smax 的元素集合

//value 在此区间中的。

Set set = zSetOperations.rangeByScore("score", 100,120);

System.out.println("打印 v1 的值在 100-120 区间的"+set.size());

//索引 start<=index<=end 的元素子集，返回泛型接口（包括 score 和 value），正序

//返回 score 和 value，set 中的前两个

Set set1 = zSetOperations.rangeWithScores("score",0,1);

//键为 K 的集合，索引 start<=index<=end 的元素子集，正序

//返回排序后的 value 中的前两个

Set set2 = zSetOperations.range("score",0,1);

//键为 K 的集合，索引 start<=index<=end 的元素子集，倒序

//返回排序后的最后两个

Set set3 = zSetOperations.reverseRange("score",0,1);

return null;

}

/**

• 根据 key 获取 value

• @param key

• @return

*/

@GetMapping("/get")

@ResponseBody

public String getRedisVal(@RequestParam String key){

String value = redisTemplate.opsForValue().get(key).toString();

return value;

}

/**