- JDK 版本信息
1.8
- SpringBoot 版本、依赖信息
org.springframework.boot
spring-boot-starter-parent
2.0.2.RELEASE
我们在 SpringBoot 中使用 Redis 时，会引入如下的 redis starter
org.springframework.boot
spring-boot-starter-data-redis
这个 starter 引入了 jedis 和 spring-data-redis 两个与 redis 核心的包。
一些核心类的定义- RedisConnection
RedisConnection 处理了与 redis 后端的通信。它提供了底层的方法，可以与redis通信，这些方法的输入和返回都是二进制的值，即 byte[]（字节数组）。
如果需要直接使用 RedisConnection，则需要在调用方法时，自己处理序列化和反序列化的问题。
- RedisTemplate
**与 RedisConnection 相比，RedisTemplate 提供了较为抽象的方法。我们在使用 RedisTemplate 时，通常需要自己去指定 key 和 value 的序列化器。如果没有指定，则
使用默认的 JdkSerializationRedisSerializer（JDK 的序列化策略），可以查看其源码如下： **
public class RedisTemplate extends RedisAccessor implements RedisOperations, BeanClassLoaderAware {
...
@SuppressWarnings("rawtypes") private @Nullable RedisSerializer keySerializer = null;
@SuppressWarnings("rawtypes") private @Nullable RedisSerializer valueSerializer = null;
@SuppressWarnings("rawtypes") private @Nullable RedisSerializer hashKeySerializer = null;
@SuppressWarnings("rawtypes") private @Nullable RedisSerializer hashValueSerializer = null;
private RedisSerializer stringSerializer = new StringRedisSerializer();
...
@Override
public void afterPropertiesSet() {
super.afterPropertiesSet();
boolean defaultUsed = false;
if (defaultSerializer == null) {
defaultSerializer = new JdkSerializationRedisSerializer(
classLoader != null ? classLoader : this.getClass().getClassLoader());
}
...
initialized = true;
}
- StringRedisTemplate
最常用的 redis 客户端，用于存取 key 和 value 都是字符串类型的数据。默认采用 String 的序列化策略（StringRedisSerializer），可以查看其源码如下：
public class StringRedisTemplate extends RedisTemplate {
public StringRedisTemplate() {
RedisSerializer stringSerializer = new StringRedisSerializer();
setKeySerializer(stringSerializer);
setValueSerializer(stringSerializer);
setHashKeySerializer(stringSerializer);
setHashValueSerializer(stringSerializer);
}
...
}
- Java Object（CityInfo）定义
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
import java.io.Serializable;
@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class CityInfo implements Serializable {
private String city;
private Double longitude;
private Double latitude;
}
- Redis 的配置类：RedisConfig
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.RedisConnection;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.JdkSerializationRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;
@Configuration
public class RedisConfig {
private final RedisConnectionFactory redisConnectionFactory;
@Autowired
public RedisConfig(RedisConnectionFactory redisConnectionFactory) {
this.redisConnectionFactory = redisConnectionFactory;
}
@Bean("RedisConnection")
RedisConnection getConn(){
return redisConnectionFactory.getConnection();
}
@Bean("RedisTemplate")
RedisTemplate getRedisTemplate(RedisConnectionFactory factory) {
RedisTemplate template = new RedisTemplate<>();
// RedisTemplate key/value 默认的序列化策略
JdkSerializationRedisSerializer redisSerializer = new JdkSerializationRedisSerializer();
// StringRedisTemplate key/value 默认的序列化策略
RedisSerializer stringSerializer = new StringRedisSerializer();
template.setConnectionFactory(factory);
template.setKeySerializer(stringSerializer);
template.setValueSerializer(redisSerializer);
return template;
}
}
- 测试用例：RedisOpTest
import com.alibaba.fastjson.JSON;
import com.imooc.ad.Application;
import com.imooc.ad.vo.CityInfo;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.redis.connection.RedisConnection;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.data.redis.serializer.JdkSerializationRedisSerializer;
import org.springframework.test.context.junit4.SpringRunner;
import java.nio.charset.StandardCharsets;
@RunWith(SpringRunner.class)
@SpringBootTest(classes = {Application.class},
webEnvironment = SpringBootTest.WebEnvironment.NONE)
public class RedisOpTest {
@Autowired
@Qualifier("RedisConnection")
private RedisConnection connection;
@Autowired
@Qualifier("RedisTemplate")
private RedisTemplate redisTemplate;
@Autowired
private StringRedisTemplate stringRedisTemplate;
@Test
public void testUseRedisConnection() {
String key = "RedisConnection";
// -----------------------------------使用 RedisConnection 存取 String 对象---------------------------------------
String value = "qinyi";
connection.set(key.getBytes(StandardCharsets.UTF_8), value.getBytes(StandardCharsets.UTF_8));
byte[] ret = connection.get(key.getBytes(StandardCharsets.UTF_8));
assert ret != null;
System.out.println(new String(ret));
connection.flushAll(); // 慎用
// -----------------------------------使用 RedisConnection 存取 Java 对象-----------------------------------------
CityInfo cityInfo = CityInfo.builder()
.city("suzhou").longitude(116.58).latitude(33.38).build();
JdkSerializationRedisSerializer serializer = new JdkSerializationRedisSerializer();
connection.set(key.getBytes(StandardCharsets.UTF_8), serializer.serialize(cityInfo));
System.out.println(serializer.deserialize(connection.get(key.getBytes(StandardCharsets.UTF_8))));
connection.flushAll(); // 慎用
}
@Test
public void testUseRedisTemplate() {
String key = "RedisTemplate";
// -----------------------------------使用 RedisTemplate 存取 Java 对象-------------------------------------------
CityInfo cityInfo = CityInfo.builder()
.city("suzhou").longitude(116.58).latitude(33.38).build();
ValueOperations valueOperations = redisTemplate.opsForValue();
valueOperations.set(key, cityInfo);
System.out.println(valueOperations.get(key));
connection.flushAll(); // 慎用
}
@Test
public void testUseStringRedisTemplate() {
String key = "StringRedisTemplate";
// -----------------------------------使用 StringRedisTemplate 存取 String 对象-----------------------------------
CityInfo cityInfo = CityInfo.builder()
.city("suzhou").longitude(116.58).latitude(33.38).build();
ValueOperations valueOperations = stringRedisTemplate.opsForValue();
valueOperations.set(key, JSON.toJSONString(cityInfo));
System.out.println(JSON.parseObject(valueOperations.get(key), CityInfo.class));
connection.flushAll(); // 慎用
}
}
- 当需要存取的数据是字符串类型时（大多数情况下），使用 StringRedisTemplate
- 当需要存取的数据是 Java Object 时，使用 RedisTemplate（需要定义好序列化策略）
- 不需要使用 RedisConnection
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