Redis缓存Object，List对象
一、到目前为止（jedis-2.2.0.jar），在Jedis中其实并没有提供这样的API对对象，或者是List对象的直接缓存，即并没有如下类似的API
jedis.set(String key, Object value)
jedis.set(String key, List<M> values)
而更多的API是类似于 jedis.set(String key, String value)或者jedis.set(String key, String ... value)
那如果我们想缓存对象，怎么办呢？
二、通过研究Jedis的API，我们发现其提供了这样的API
jedis.set(byte[], byte[]),
通过这个API，很显然我们能够实现
jedis.set(String key, Object value)
jedis.set(String key, List<M> values)
我们需要关注的就是在cache的时候将Object和List对象转换成字节数组并且需要提供将字节数组转换成对象返回。
三、考虑到扩展性，设计了3个类，抽象父类SerializeTranscoder， 子类ListTranscoder和ObjectsTranscoder 以及一个Unit test 类 用于模拟对象，list对象和字节数组的转换，即Serialize和de-searilize的过程。
1. SerializeTranscoder
package com.chuanliu.platform.activity.basic.util.serialize;
import java.io.Closeable;
import org.apache.log4j.Logger;
/**
* @author Josh Wang(Sheng)
*
* @email josh_wang23@hotmail.com
*/
public abstract class SerializeTranscoder {
protected static Logger logger = Logger.getLogger(SerializeTranscoder.class);
public abstract byte[] serialize(Object value);
public abstract Object deserialize(byte[] in);
public void close(Closeable closeable) {
if (closeable != null) {
try {
closeable.close();
} catch (Exception e) {
logger.info("Unable to close " + closeable, e);
}
}
}
}
2. ListTranscoder
package com.chuanliu.platform.activity.basic.util.serialize;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import com.chuanliu.platform.activity.basic.util.LoggerUtils;
/**
* Case 1.
* Jedis does not support cache the Object directly, the Objects needed to be
* serialized and de-serialized
*
* Case 2.
* coming very soon...
*
* @author Josh Wang(Sheng)
*
* @email josh_wang23@hotmail.com
*/
public class ListTranscoder<M extends Serializable> extends SerializeTranscoder {
@SuppressWarnings("unchecked")
public List<M> deserialize(byte[] in) {
List<M> list = new ArrayList<>();
ByteArrayInputStream bis = null;
ObjectInputStream is = null;
try {
if (in != null) {
bis = new ByteArrayInputStream(in);
is = new ObjectInputStream(bis);
while (true) {
M m = (M)is.readObject();
if (m == null) {
break;
}
list.add(m);
}
is.close();
bis.close();
}
} catch (IOException e) {
LoggerUtils.error(logger, String.format("Caught IOException decoding %d bytes of data",
in == null ? 0 : in.length) + e);
} catch (ClassNotFoundException e) {
LoggerUtils.error(logger, String.format("Caught CNFE decoding %d bytes of data",
in == null ? 0 : in.length) + e);
} finally {
close(is);
close(bis);
}
return list;
}
@SuppressWarnings("unchecked")
@Override
public byte[] serialize(Object value) {
if (value == null)
throw new NullPointerException("Can't serialize null");
List<M> values = (List<M>) value;
byte[] results = null;
ByteArrayOutputStream bos = null;
ObjectOutputStream os = null;
try {
bos = new ByteArrayOutputStream();
os = new ObjectOutputStream(bos);
for (M m : values) {
os.writeObject(m);
}
// os.writeObject(null);
os.close();
bos.close();
results = bos.toByteArray();
} catch (IOException e) {
throw new IllegalArgumentException("Non-serializable object", e);
} finally {
close(os);
close(bos);