先看实例：

...

@Autowired

RedisTemplate redisTemplate;

public void testGetUserByName(){

User user = new User();

user.setUserName("用户1");

redisTemplate.opsForValue().set("user1", user);

Assert.assertEquals(user.getUserName(), ((User) jedisClient.get("user1")).getUserName());

}

//User已经实现了Serializable接口

//配置的是org.springframework.data.redis.serializer.StringRedisSerializer

...

使用StringRedisSerializer直接缓存Object会出现转换错误：

java.lang.ClassCastException: dev.entity.User cannot be cast to java.lang.String

at org.springframework.data.redis.serializer.StringRedisSerializer.serialize(StringRedisSerializer.java:32)

at org.springframework.data.redis.core.AbstractOperations.rawValue(AbstractOperations.java:112)

at org.springframework.data.redis.core.DefaultValueOperations.set(DefaultValueOperations.java:168)

at dev.dao.RedisTest.testGetUserByName(RedisTest.java:22)

...

解决方法

StringRedisTemplate相当于RedisTemplate的实现。

缓存时需要把Object类转为byte[]再存到redis中，反之要从redis中获取byte[]再转成Object。

看了很多人的实现方法，感觉这个实现最优雅便捷。最主要的转换代码如下：

/**

* 描述 : .

*

*

*

*

* @param bytes

* @return

*/

private Object toObject(byte[] bytes) {

Object obj = null;

try {

ByteArrayInputStream bis = new ByteArrayInputStream(bytes);

ObjectInputStream ois = new ObjectInputStream(bis);

obj = ois.readObject();

ois.close();

bis.close();

} catch (IOException ex) {

ex.printStackTrace();

} catch (ClassNotFoundException ex) {

ex.printStackTrace();

}

return obj;

}

private byte[] toByteArray(Object obj) {

byte[] bytes = null;

ByteArrayOutputStream bos = new ByteArrayOutputStream();

try {

ObjectOutputStream oos = new ObjectOutputStream(bos);

oos.writeObject(obj);

oos.flush();

bytes = bos.toByteArray();

oos.close();

bos.close();

} catch (IOException ex) {

ex.printStackTrace();

}

return bytes;

}

}

相当于封装了一个处理Object缓存的类，之后用这个类与redis做交流。

package dev.dao;

import dev.cache.JedisClient;

import dev.entity.User;

import org.junit.Assert;

import org.junit.Test;

import org.junit.runner.RunWith;

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

import org.springframework.test.context.ContextConfiguration;

import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)

@ContextConfiguration("classpath:/spring/spring-redis.xml")

public class RedisTest {

@Autowired

JedisClient jedisClient;

@Test

public void testGetUserByName(){

User user = new User();

user.setUserName("用户1");

jedisClient.put("user1", user);

Assert.assertEquals(user.getUserName(), ((User) jedisClient.get("user1")).getUserName());

}

}

//测试成功