How to store objects in list in redis

If you need to use Redis to store List objects, and the list does not need to be operated, you can store it in the MC way. However, clients such as Jedis do not provide an API. You can have Two ideas to implement:

1. Serialize elements separately, and then set to store

2. Serialize List objects, set to store

These two methods are similar to MC Object method storage, using this method means giving up the operation method provided by Redis for List.

import net.spy.memcached.compat.CloseUtil;
import net.spy.memcached.compat.log.Logger;
import net.spy.memcached.compat.log.LoggerFactory;
import redis.clients.jedis.Client;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;
import java.io.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
/**
 * Created by IntelliJ IDEA.
 * User: lifeng.xu
 * Date: 12-6-11
 * Time: 上午11:10
 * To change this template use File | Settings | File Templates.
 */
public class JedisTest {
    private static Logger logger = LoggerFactory.getLogger(JedisTest.class);
    /**
     * Jedis Pool for Jedis Resource
     * @return
     */
    public static JedisPool buildJedisPool(){
        JedisPoolConfig config = new JedisPoolConfig();
        config.setMaxActive(1);
        config.setMinIdle(50);
        config.setMaxIdle(3000);
        config.setMaxWait(5000);
        JedisPool jedisPool = new JedisPool(config,
                "*****", ****);
        return jedisPool;
    }
    /**
     * Test Data
     * @return
     */
    public static List<User> buildTestData(){
        User a = new User();
        a.setName("a");
        User b = new User();
        b.setName("b");
        List<User> list = new ArrayList<User>();
        list.add(a);
        list.add(b);
        return list;
    }
    /**
     * Test for
     */
    public static void testSetElements(){
        List<User> testData = buildTestData();
        Jedis jedis = buildJedisPool().getResource();
        String key = "testSetElements" + new Random(1000).nextInt();
        jedis.set(key.getBytes(), ObjectsTranscoder.serialize(testData));
        //验证
        byte[] in = jedis.get(key.getBytes());
        List<User> list = ObjectsTranscoder.deserialize(in);
        for(User user : list){
            System.out.println("testSetElements user name is:" + user.getName());
        }
    }
    public static void testSetEnsemble(){
        List<User> testData = buildTestData();
        Jedis jedis = buildJedisPool().getResource();
        String key = "testSetEnsemble" + new Random(1000).nextInt();
        jedis.set(key.getBytes(), ListTranscoder.serialize(testData));
        //验证
        byte[] in = jedis.get(key.getBytes());
        List<User> list = (List<User>)ListTranscoder.deserialize(in);
        for(User user : list){
            System.out.println("testSetEnsemble user name is:" + user.getName());
        }
    }
    public static void main(String[] args) {
        testSetElements();
        testSetEnsemble();
    }
    public static void close(Closeable closeable) {
        if (closeable != null) {
            try {
                closeable.close();
            } catch (Exception e) {
                logger.info("Unable to close %s", closeable, e);
            }
        }
    }
    static class User implements Serializable{
        String name;
        public String getName() {
            return name;
        }
        public void setName(String name) {
            this.name = name;
        }
    }
    static class ObjectsTranscoder{
        
        public static byte[] serialize(List<User> value) {
            if (value == null) {
                throw new NullPointerException("Can&#39;t serialize null");
            }
            byte[] rv=null;
            ByteArrayOutputStream bos = null;
            ObjectOutputStream os = null;
            try {
                bos = new ByteArrayOutputStream();
                os = new ObjectOutputStream(bos);
                for(User user : value){
                    os.writeObject(user);
                }
                os.writeObject(null);
                os.close();
                bos.close();
                rv = bos.toByteArray();
            } catch (IOException e) {
                throw new IllegalArgumentException("Non-serializable object", e);
            } finally {
                close(os);
                close(bos);
            }
            return rv;
        }
        public static List<User> deserialize(byte[] in) {
            List<User> list = new ArrayList<User>();
            ByteArrayInputStream bis = null;
            ObjectInputStream is = null;
            try {
                if(in != null) {
                    bis=new ByteArrayInputStream(in);
                    is=new ObjectInputStream(bis);
                    while (true) {
                        User user = (User) is.readObject();
                        if(user == null){
                            break;
                        }else{
                            list.add(user);
                        }
                    }
                    is.close();
                    bis.close();
                }
            } catch (IOException e) {
                logger.warn("Caught IOException decoding %d bytes of data",
                        in == null ? 0 : in.length, e);
            } catch (ClassNotFoundException e) {
                logger.warn("Caught CNFE decoding %d bytes of data",
                        in == null ? 0 : in.length, e);
            } finally {
                CloseUtil.close(is);
                CloseUtil.close(bis);
            }
            return list;
        }
    }
    
    static class ListTranscoder{
        public static byte[] serialize(Object value) {
            if (value == null) {
                throw new NullPointerException("Can&#39;t serialize null");
            }
            byte[] rv=null;
            ByteArrayOutputStream bos = null;
            ObjectOutputStream os = null;
            try {
                bos = new ByteArrayOutputStream();
                os = new ObjectOutputStream(bos);
                os.writeObject(value);
                os.close();
                bos.close();
                rv = bos.toByteArray();
            } catch (IOException e) {
                throw new IllegalArgumentException("Non-serializable object", e);
            } finally {
                close(os);
                close(bos);
            }
            return rv;
        }
        public static Object deserialize(byte[] in) {
            Object rv=null;
            ByteArrayInputStream bis = null;
            ObjectInputStream is = null;
            try {
                if(in != null) {
                    bis=new ByteArrayInputStream(in);
                    is=new ObjectInputStream(bis);
                    rv=is.readObject();
                    is.close();
                    bis.close();
                }
            } catch (IOException e) {
                logger.warn("Caught IOException decoding %d bytes of data",
                        in == null ? 0 : in.length, e);
            } catch (ClassNotFoundException e) {
                logger.warn("Caught CNFE decoding %d bytes of data",
                        in == null ? 0 : in.length, e);
            } finally {
                CloseUtil.close(is);
                CloseUtil.close(bis);
            }
            return rv;
        }
    }
}

PS: The list storage in Redsi does not encapsulate the API for Object. Is it also inclined to store only the fields used instead of storing the Object itself? Redis is an In-Mem product and will be used in our application.

For more Redis-related technical articles, please visit the Redis Tutorial column to learn!

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