Redis的Java客戶端

Jedis執行緒不安全，lettuce執行緒安全

Jedis

測驗

引入依賴

<dependencies>
    <dependency>
        <groupId>redis.clients</groupId>
        <artifactId>jedis</artifactId>
        <version>3.7.0</version>
    </dependency>
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter</artifactId>
        <version>5.7.0</version>
    </dependency>
</dependencies>

Test.java

public class JedisTest {
    private Jedis jedis;

    @BeforeEach
    void setUp() {
        //1.建立連接
        jedis=new Jedis("192.168.164.128",6379);
        //2.設定密碼
        jedis.auth("123456");
        //3.選擇庫
        jedis.select(0);
    }

    @Test
    void testString() {
        //存入
        String result=jedis.set("name","熊哥");
        System.out.println("result="+result);
        //獲取
        String name=jedis.get("name");
        System.out.println("name="+name);

        //存入
        jedis.hset("user:1","name","Jack");
        jedis.hset("user:1","age","21");
        //獲取
        Map<String, String> map = jedis.hgetAll("user:1");
        System.out.println(map);
    }

    @AfterEach
    void tearDown() {
        //關閉連接
        if(jedis!=null){
            jedis.close();
        }
    }
}

Jedis連接池

Jedis本身是執行緒不安全的，且頻繁的創建和銷毀連接有性能損耗，因此推薦使用Jedis連接池代替Jedis直接連接

JedisConnectionFactory.java

public class JedisConnectionFactory {
    //連接池物件
    private static final JedisPool jedisPool;

    //初始化
    static {
        //配置連接池
        JedisPoolConfig poolConfig = new JedisPoolConfig();
        poolConfig.setMaxTotal(8);  //最大8個連接
        poolConfig.setMaxIdle(8);   //最大空閑數量
        poolConfig.setMinIdle(0);   //最小空閑數量
        poolConfig.setMaxWaitMillis(1000);  //當池內沒有回傳物件時最大等待時間

        //創建連接池物件(JedisPoolConfig,ip,port，timeout,password)
        jedisPool=new JedisPool(poolConfig,"192.168.164.128",6379,1000,"123456");
    }
    public static Jedis getJedis(){
        return jedisPool.getResource();
    }
}

Test.java（改變建立連接的陳述句）

public class JedisTest {
    private Jedis jedis;

    @BeforeEach
    void setUp() {
        //1.建立連接
//        jedis=new Jedis("192.168.164.128",6379);
        jedis= JedisConnectionFactory.getJedis();
        //2.設定密碼
        jedis.auth("123456");
        //3.選擇庫
        jedis.select(0);
    }

    @Test
    void testString() {
        //存入
        String result=jedis.set("name","熊哥");
        System.out.println("result="+result);
        //獲取
        String name=jedis.get("name");
        System.out.println("name="+name);

        //存入
        jedis.hset("user:1","name","Jack");
        jedis.hset("user:1","age","21");
        //獲取
        Map<String, String> map = jedis.hgetAll("user:1");
        System.out.println(map);
    }

    @AfterEach
    void tearDown() {
        //關閉連接
        if(jedis!=null){
            jedis.close();
        }
    }
}

SpringDataRedis

SpringDataRedis中提供RedisTemplate工具類，封裝了各種對Redis的操作，springboot2.x以前默認支持Jedis，以后默認支持lettuce

依賴

<!--redis-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
<!--common-pool-->
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-pool2</artifactId>
</dependency>

application.yaml

spring:
  redis:
    host: 192.168.164.128
    port: 6379
    password: 123456
    database: 0
    lettuce:
      pool:
        max-active: 8
        max-idle: 8
        min-idle: 0
        max-wait: 100ms

Test.java

@SpringBootTest
class RedisDemoApplicationTests {
    @Resource
    private RedisTemplate redisTemplate;

    @Test
    void contextLoads() {
        //寫入一條String資料
        redisTemplate.opsForValue().set("name","王五");
        //獲取
        Object name=redisTemplate.opsForValue().get("name");
        System.out.println(name);
    }
}

序列化以實作跨平臺存盤（在上面的基礎上修改）

添加配置類RedisConfig.java

@Configuration
public class RedisConfig {
    @Bean
    public RedisTemplate<String,Object> redisTemplate(RedisConnectionFactory connectionFactory){
        //創建RedisTemplate物件
        RedisTemplate<String, Object> template = new RedisTemplate<>();
        //設定連接工廠
        template.setConnectionFactory(connectionFactory);
        //創建JSON序列化工具
        GenericJackson2JsonRedisSerializer jsonRedisSerializer = new GenericJackson2JsonRedisSerializer();
        //設定Key的序列化
        template.setKeySerializer(RedisSerializer.string());
        template.setHashKeySerializer(RedisSerializer.string());
        //設定Value的序列化
        template.setValueSerializer(jsonRedisSerializer);
        template.setHashValueSerializer(jsonRedisSerializer);
        //回傳
        return template;
    }
}

Test.java中修改下面這行

private RedisTemplate<String,Object> redisTemplate;

若linux下還是顯示亂碼，在啟動客戶端時最后加上 --raw

StringRedisTemplate(上面的經典白學)

Spring默認提供了一個StringRedisTemplate類，它的key和value的序列化方式默認是String方式，省去了自定義RedisTemplate的程序

Test.java

@SpringBootTest
public class RedisStringTest {
    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Test
    void contextLoads() {
        //寫入一條String資料
        stringRedisTemplate.opsForValue().set("name","王五");
        //獲取
        Object name=stringRedisTemplate.opsForValue().get("name");
        System.out.println(name);
    }
}

標籤：NoSQL

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