Redis緩存Object，List對象

一、到目前為止（jedis-2.2.0.jar），在Jedis中其實並沒有提供這樣的API對對象，或者是List對象的直接緩存，即並沒有如下類似的API

jedis.set(String key, Object value)

jedis.set(String key, List<M> values)

而更多的API是類似於 jedis.set(String key, String value)或者jedis.set(String key, String ... value)

那如果我們想緩存對象，怎么辦呢？

二、通過研究Jedis的API，我們發現其提供了這樣的API

jedis.set(byte[], byte[]),

通過這個API，很顯然我們能夠實現

jedis.set(String key, Object value)

jedis.set(String key, List<M> values)

我們需要關注的就是在cache的時候將Object和List對象轉換成字節數組並且需要提供將字節數組轉換成對象返回。

三、考慮到擴展性，設計了3個類，抽象父類SerializeTranscoder， 子類ListTranscoder和ObjectsTranscoder 以及一個Unit test 類 用於模擬對象，list對象和字節數組的轉換，即Serialize和de-searilize的過程。

1. SerializeTranscoder

package com.chuanliu.platform.activity.basic.util.serialize;

import java.io.Closeable; import org.apache.log4j.Logger; /** * @author Josh Wang(Sheng) * * @email [e-mail] */ 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 [e-mail] */ 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);   }     return results;  }  }

3. ObjectsTranscoder

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 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 [e-mail] */ public class ObjectsTranscoder<M extends Serializable> extends SerializeTranscoder {   @SuppressWarnings("unchecked")  @Override  public byte[] serialize(Object value) {   if (value == null) {    throw new NullPointerException("Can't serialize null");   }   byte[] result = null;   ByteArrayOutputStream bos = null;   ObjectOutputStream os = null;   try {    bos = new ByteArrayOutputStream();    os = new ObjectOutputStream(bos);    M m = (M) value;    os.writeObject(m);    os.close();    bos.close();    result = bos.toByteArray();   } catch (IOException e) {    throw new IllegalArgumentException("Non-serializable object", e);   } finally {    close(os);    close(bos);   }   return result;  }  @SuppressWarnings("unchecked")  @Override  public M deserialize(byte[] in) {   M result = null;   ByteArrayInputStream bis = null;   ObjectInputStream is = null;   try {   if (in != null) {    bis = new ByteArrayInputStream(in);    is = new ObjectInputStream(bis);    result = (M) is.readObject();    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 result;  } }

4. TestSerializerTranscoder

package com.chuanliu.platform.activity.basic.util;

import java.io.Serializable; import java.util.ArrayList; import java.util.List; import org.junit.Test; import com.chuanliu.platform.activity.basic.util.serialize.ListTranscoder; import com.chuanliu.platform.activity.basic.util.serialize.ObjectsTranscoder; /** * @author Josh Wang(Sheng) * * @email [e-mail] */ public class TestSerializerTranscoder implements Serializable {   private static final long serialVersionUID = -1941046831377985500L;  public TestSerializerTranscoder() {    }  @Test  public void testObject() {   List<TestUser> lists = buildTestData();     TestUser userA = lists.get(0);     ObjectsTranscoder<TestUser> objTranscoder = new ObjectsTranscoder<>();     byte[] result1 = objTranscoder.serialize(userA);     TestUser userA_userA = objTranscoder.deserialize(result1);     System.out.println(userA_userA.getName() + "\t" + userA_userA.getAge());  }   @Test  public void testList() {   List<TestUser> lists = buildTestData();     ListTranscoder<TestUser> listTranscoder = new ListTranscoder<>();     byte[] result1 = listTranscoder.serialize(lists);     List<TestUser> results = listTranscoder.deserialize(result1);    for (TestUser user : results) {    System.out.println(user.getName() + "\t" + user.getAge());   }    }   private static List<TestUser> buildTestData() {   TestSerializerTranscoder tst = new TestSerializerTranscoder();   TestUser userA = tst.new TestUser();   userA.setName("lily"); userA.setAge(25);   TestUser userB = tst.new TestUser(); userB.setName("Josh Wang");   userB.setAge(28); List<TestUser> list = new ArrayList<TestUser>(); list.add(userA); list.add(userB); return list; }   class TestUser implements Serializable {   private static final long serialVersionUID = 1L;    private String name;       private int age;       public String getName() {     return name;    }    public void setName(String name) {     this.name = name;    }    public int getAge() {     return age;    }    public void setAge(int age) {     this.age = age;    }      }   }

四、通過以上幾步后，即可使用Jedis的API進行對象的緩存並將從緩存中返回的二進制數組轉換成原始的對象或者是List對象了。