redisTemplate操作指定库

与其他部门同时联调时，他们的redis缓存不一定是写在 db0库。而项目中默认的RedistTemplate只能读取db0。可考虑如下解决方式：

适用于缓存提供方不方便调整db的情况，最好还是让提供方直接写到默认缓存库

1.引入maven依赖

        
            redis.clients
            jedis
            
            2.9.0
        

2.nacos配置

redis:
  host: 192.168.100.xxx
  port: 6379
  password:
  maxIdle: 10
  minIdle: 5
  timeout: 1000
  # 可以指定多个，用“,”隔开，写在第一个的为defaultDB
  dbs: 0,1,2

3.代码

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.connection.RedisPassword;
import org.springframework.data.redis.connection.RedisStandaloneConfiguration;
import org.springframework.data.redis.connection.jedis.JedisClientConfiguration;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;
import redis.clients.jedis.JedisPoolConfig;

import javax.annotation.PostConstruct;
import java.util.HashMap;
import java.util.List;
import java.util.Map;


@Component
@Slf4j
public class RedisConfig {
    
    @Value("${redis.host}")
    private String hostName;
    
    @Value("${redis.port}")
    private int port;
    
    @Value("${redis.password}")
    private String passWord;
    
    @Value("${redis.maxIdle}")
    private int maxIdl;
    
    @Value("${redis.minIdle}")
    private int minIdl;
    
    @Value("${redis.timeout}")
    private int timeout;
    
    @Value("#{'${redis.dbs}'.split(',')}")
    private List dbs;
    
    private int defaultDb;
    
    private static Map redisTemplateMap = new HashMap<>();

    
    @PostConstruct
    public void initRedisTemp() throws Exception {
        log.info("###### START 初始化 Redis 连接池 START ######");
        defaultDb = dbs.get(0);
        for (Integer db : dbs) {
            log.info("###### 正在加载Redis-db-" + db + " ######");
            redisTemplateMap.put(db, redisTemplateObject(db));
        }
        log.info("###### END 初始化 Redis 连接池 END ######");
    }

    
    private StringRedisTemplate redisTemplateObject(Integer dbIndex) throws Exception {
        StringRedisTemplate redisTemplateObject = new StringRedisTemplate();
        redisTemplateObject.setConnectionFactory(redisConnectionFactory(jedisPoolConfig(), dbIndex));
        redisTemplateObject.afterPropertiesSet();
        return redisTemplateObject;
    }

    
    private JedisPoolConfig jedisPoolConfig() {
        JedisPoolConfig poolConfig = new JedisPoolConfig();
        poolConfig.setMaxIdle(maxIdl);
        poolConfig.setMinIdle(minIdl);
        poolConfig.setTestOnBorrow(true);
        poolConfig.setTestOnReturn(true);
        poolConfig.setTestWhileIdle(true);
        poolConfig.setNumTestsPerEvictionRun(10);
        poolConfig.setTimeBetweenEvictionRunsMillis(60000);
        // 当池内没有可用的连接时，最大等待时间
        poolConfig.setMaxWaitMillis(10000);
        // ------其他属性根据需要自行添加-------------
        return poolConfig;
    }

    
    private RedisConnectionFactory redisConnectionFactory(JedisPoolConfig jedisPoolConfig, int db) {
        // 单机版jedis
        RedisStandaloneConfiguration redisStandaloneConfiguration = new RedisStandaloneConfiguration();
        // 设置redis服务器的host或者ip地址
        redisStandaloneConfiguration.setHostName(hostName);
        // 设置默认使用的数据库
        redisStandaloneConfiguration.setDatabase(db);
        // 设置密码
        redisStandaloneConfiguration.setPassword(RedisPassword.of(passWord));
        // 设置redis的服务的端口号
        redisStandaloneConfiguration.setPort(port);

        // 获得默认的连接池构造器
        JedisClientConfiguration.JedisPoolingClientConfigurationBuilder jpcb = (JedisClientConfiguration.JedisPoolingClientConfigurationBuilder) JedisClientConfiguration.builder();
        // 指定jedisPoolConifig来修改默认的连接池构造器
        jpcb.poolConfig(jedisPoolConfig);
        // 通过构造器来构造jedis客户端配置
        JedisClientConfiguration jedisClientConfiguration = jpcb.build();
        // 单机配置 + 客户端配置 = jedis连接工厂
        return new JedisConnectionFactory(redisStandaloneConfiguration, jedisClientConfiguration);
    }

    
    public StringRedisTemplate getRedisTemplateByDb(int db) {
        return redisTemplateMap.get(db);
    }

    
    public StringRedisTemplate getRedisTemplate() {
        return redisTemplateMap.get(defaultDb);
    }

}

@Autowired
RedisConfig redisConfig;

fun xx(){
    //得到操作db0的连接(默认)
    redisConfig.getRedisTemplate().xxx

    //得到操作db2的连接
    redisConfig.getRedisTemplateByDb(2).xxx
}

缺点：目前只支持单机
优点：可配置，为每个库建立连接，并发时产生切换的开销小