Specific analysis of how Java uses Redis to implement message queues

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This article introduces the sample code of Java using Redis to implement message queue, and shares it with everyone. The details are as follows:

Application scenarios

Why use redis?

Binary storage, java serialized transmission, high number of IO connections, frequent connections

1. Serialization

A java serialization tool is written here, which mainly converts objects into byte arrays and deserializes them into java objects based on byte arrays; mainly using ByteArrayOutputStream and ByteArrayInputStream ; Note: Every object that needs to be serialized must implement the Serializable interface;

The code is as follows:

package Utils;
import java.io.*;
/**
 * Created by Kinglf on 2016/10/17.
 */
public class ObjectUtil {
 /**
  * 对象转byte[]
  * @param obj
  * @return
  * @throws IOException
  */
 public static byte[] object2Bytes(Object obj) throws IOException{
  ByteArrayOutputStream bo=new ByteArrayOutputStream();
  ObjectOutputStream oo=new ObjectOutputStream(bo);
  oo.writeObject(obj);
  byte[] bytes=bo.toByteArray();
  bo.close();
  oo.close();
  return bytes;
 }
 /**
  * byte[]转对象
  * @param bytes
  * @return
  * @throws Exception
  */
 public static Object bytes2Object(byte[] bytes) throws Exception{
  ByteArrayInputStream in=new ByteArrayInputStream(bytes);
  ObjectInputStream sIn=new ObjectInputStream(in);
  return sIn.readObject();
 }
}

2. Message class (implementing Serializable interface)

##

package Model;

import java.io.Serializable;

/**
 * Created by Kinglf on 2016/10/17.
 */
public class Message implements Serializable {

 private static final long serialVersionUID = -389326121047047723L;
 private int id;
 private String content;
 public Message(int id, String content) {
  this.id = id;
  this.content = content;
 }
 public int getId() {
  return id;
 }
 public void setId(int id) {
  this.id = id;
 }
 public String getContent() {
  return content;
 }
 public void setContent(String content) {
  this.content = content;
 }
}

3. Redis operation

Using redis as a queue, we use the push and pop operations of the list in redis;

Combined with the characteristics of the queue:

Only allowed to insert new elements at one end only at the end of the queue FIFO: first in first out principle In Redis, lpush head in (rpop tail out) or rpush tail in (lpop head out) can be To meet the requirements, the list medicine push or pop objects in Redis only need to be converted into byte[]

java uses Jedis for Redis storage and Redis connection pool settings

Code above:

package Utils;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
 * Created by Kinglf on 2016/10/17.
 */
public class JedisUtil {
 private static String JEDIS_IP;
 private static int JEDIS_PORT;
 private static String JEDIS_PASSWORD;
 private static JedisPool jedisPool;
 static {
  //Configuration自行写的配置文件解析类,继承自Properties
  Configuration conf=Configuration.getInstance();
  JEDIS_IP=conf.getString("jedis.ip","127.0.0.1");
  JEDIS_PORT=conf.getInt("jedis.port",6379);
  JEDIS_PASSWORD=conf.getString("jedis.password",null);
  JedisPoolConfig config=new JedisPoolConfig();
  config.setMaxActive(5000);
  config.setMaxIdle(256);
  config.setMaxWait(5000L);
  config.setTestOnBorrow(true);
  config.setTestOnReturn(true);
  config.setTestWhileIdle(true);
  config.setMinEvictableIdleTimeMillis(60000L);
  config.setTimeBetweenEvictionRunsMillis(3000L);
  config.setNumTestsPerEvictionRun(-1);
  jedisPool=new JedisPool(config,JEDIS_IP,JEDIS_PORT,60000);
 }
 /**
  * 获取数据
  * @param key
  * @return
  */
 public static String get(String key){
  String value=null;
  Jedis jedis=null;
  try{
   jedis=jedisPool.getResource();
   value=jedis.get(key);
  }catch (Exception e){
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();
  }finally {
   close(jedis);
  }
  return value;
 }

 private static void close(Jedis jedis) {
  try{
   jedisPool.returnResource(jedis);
  }catch (Exception e){
   if(jedis.isConnected()){
    jedis.quit();
    jedis.disconnect();
   }
  }
 }
 public static byte[] get(byte[] key){
  byte[] value = null;
  Jedis jedis = null;
  try {
   jedis = jedisPool.getResource();
   value = jedis.get(key);
  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();
  } finally {
   //返还到连接池
   close(jedis);
  }

  return value;
 }

 public static void set(byte[] key, byte[] value) {

  Jedis jedis = null;
  try {
   jedis = jedisPool.getResource();
   jedis.set(key, value);
  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();
  } finally {
   //返还到连接池
   close(jedis);
  }
 }

 public static void set(byte[] key, byte[] value, int time) {

  Jedis jedis = null;
  try {
   jedis = jedisPool.getResource();
   jedis.set(key, value);
   jedis.expire(key, time);
  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();
  } finally {
   //返还到连接池
   close(jedis);
  }
 }

 public static void hset(byte[] key, byte[] field, byte[] value) {
  Jedis jedis = null;
  try {
   jedis = jedisPool.getResource();
   jedis.hset(key, field, value);
  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();
  } finally {
   //返还到连接池
   close(jedis);
  }
 }

 public static void hset(String key, String field, String value) {
  Jedis jedis = null;
  try {
   jedis = jedisPool.getResource();
   jedis.hset(key, field, value);
  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();
  } finally {
   //返还到连接池
   close(jedis);
  }
 }

 /**
  * 获取数据
  *
  * @param key
  * @return
  */
 public static String hget(String key, String field) {

  String value = null;
  Jedis jedis = null;
  try {
   jedis = jedisPool.getResource();
   value = jedis.hget(key, field);
  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();
  } finally {
   //返还到连接池
   close(jedis);
  }

  return value;
 }
 /**
  * 获取数据
  *
  * @param key
  * @return
  */
 public static byte[] hget(byte[] key, byte[] field) {

  byte[] value = null;
  Jedis jedis = null;
  try {
   jedis = jedisPool.getResource();
   value = jedis.hget(key, field);
  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();
  } finally {
   //返还到连接池
   close(jedis);
  }

  return value;
 }
 public static void hdel(byte[] key, byte[] field) {

  Jedis jedis = null;
  try {
   jedis = jedisPool.getResource();
   jedis.hdel(key, field);
  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();
  } finally {
   //返还到连接池
   close(jedis);
  }
 }
 /**
  * 存储REDIS队列 顺序存储
  * @param key reids键名
  * @param value 键值
  */
 public static void lpush(byte[] key, byte[] value) {

  Jedis jedis = null;
  try {
   jedis = jedisPool.getResource();
   jedis.lpush(key, value);
  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();
  } finally {
   //返还到连接池
   close(jedis);
  }
 }

 /**
  * 存储REDIS队列 反向存储
  * @param key reids键名
  * @param value 键值
  */
 public static void rpush(byte[] key, byte[] value) {

  Jedis jedis = null;
  try {

   jedis = jedisPool.getResource();
   jedis.rpush(key, value);

  } catch (Exception e) {

   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();

  } finally {

   //返还到连接池
   close(jedis);

  }
 }

 /**
  * 将列表 source 中的最后一个元素(尾元素)弹出，并返回给客户端
  * @param key reids键名
  * @param destination 键值
  */
 public static void rpoplpush(byte[] key, byte[] destination) {

  Jedis jedis = null;
  try {

   jedis = jedisPool.getResource();
   jedis.rpoplpush(key, destination);

  } catch (Exception e) {

   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();

  } finally {

   //返还到连接池
   close(jedis);

  }
 }

 /**
  * 获取队列数据
  * @param key 键名
  * @return
  */
 public static List lpopList(byte[] key) {

  List list = null;
  Jedis jedis = null;
  try {

   jedis = jedisPool.getResource();
   list = jedis.lrange(key, 0, -1);

  } catch (Exception e) {

   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();

  } finally {

   //返还到连接池
   close(jedis);

  }
  return list;
 }
 /**
  * 获取队列数据
  * @param key 键名
  * @return
  */
 public static byte[] rpop(byte[] key) {

  byte[] bytes = null;
  Jedis jedis = null;
  try {

   jedis = jedisPool.getResource();
   bytes = jedis.rpop(key);

  } catch (Exception e) {

   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();

  } finally {

   //返还到连接池
   close(jedis);

  }
  return bytes;
 }
 public static void hmset(Object key, Map hash) {
  Jedis jedis = null;
  try {
   jedis = jedisPool.getResource();
   jedis.hmset(key.toString(), hash);
  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();

  } finally {
   //返还到连接池
   close(jedis);

  }
 }
 public static void hmset(Object key, Map hash, int time) {
  Jedis jedis = null;
  try {

   jedis = jedisPool.getResource();
   jedis.hmset(key.toString(), hash);
   jedis.expire(key.toString(), time);
  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();

  } finally {
   //返还到连接池
   close(jedis);

  }
 }
 public static List hmget(Object key, String... fields) {
  List result = null;
  Jedis jedis = null;
  try {

   jedis = jedisPool.getResource();
   result = jedis.hmget(key.toString(), fields);

  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();

  } finally {
   //返还到连接池
   close(jedis);

  }
  return result;
 }

 public static Set hkeys(String key) {
  Set result = null;
  Jedis jedis = null;
  try {
   jedis = jedisPool.getResource();
   result = jedis.hkeys(key);

  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();

  } finally {
   //返还到连接池
   close(jedis);

  }
  return result;
 }
 public static List lrange(byte[] key, int from, int to) {
  List result = null;
  Jedis jedis = null;
  try {
   jedis = jedisPool.getResource();
   result = jedis.lrange(key, from, to);

  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();

  } finally {
   //返还到连接池
   close(jedis);

  }
  return result;
 }
 public static Map hgetAll(byte[] key) {
  Map result = null;
  Jedis jedis = null;
  try {
   jedis = jedisPool.getResource();
   result = jedis.hgetAll(key);
  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();

  } finally {
   //返还到连接池
   close(jedis);
  }
  return result;
 }

 public static void del(byte[] key) {

  Jedis jedis = null;
  try {
   jedis = jedisPool.getResource();
   jedis.del(key);
  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();
  } finally {
   //返还到连接池
   close(jedis);
  }
 }

 public static long llen(byte[] key) {

  long len = 0;
  Jedis jedis = null;
  try {
   jedis = jedisPool.getResource();
   jedis.llen(key);
  } catch (Exception e) {
   //释放redis对象
   jedisPool.returnBrokenResource(jedis);
   e.printStackTrace();
  } finally {
   //返还到连接池
   close(jedis);
  }
  return len;
 }
}

Fourth, Configuration is mainly used to read Redis configuration information

package Utils;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

/**
 * Created by Kinglf on 2016/10/17.
 */
public class Configuration extends Properties {

 private static final long serialVersionUID = -2296275030489943706L;
 private static Configuration instance = null;

 public static synchronized Configuration getInstance() {
  if (instance == null) {
   instance = new Configuration();
  }
  return instance;
 }


 public String getProperty(String key, String defaultValue) {
  String val = getProperty(key);
  return (val == null || val.isEmpty()) ? defaultValue : val;
 }

 public String getString(String name, String defaultValue) {
  return this.getProperty(name, defaultValue);
 }

 public int getInt(String name, int defaultValue) {
  String val = this.getProperty(name);
  return (val == null || val.isEmpty()) ? defaultValue : Integer.parseInt(val);
 }

 public long getLong(String name, long defaultValue) {
  String val = this.getProperty(name);
  return (val == null || val.isEmpty()) ? defaultValue : Integer.parseInt(val);
 }

 public float getFloat(String name, float defaultValue) {
  String val = this.getProperty(name);
  return (val == null || val.isEmpty()) ? defaultValue : Float.parseFloat(val);
 }

 public double getDouble(String name, double defaultValue) {
  String val = this.getProperty(name);
  return (val == null || val.isEmpty()) ? defaultValue : Double.parseDouble(val);
 }

 public byte getByte(String name, byte defaultValue) {
  String val = this.getProperty(name);
  return (val == null || val.isEmpty()) ? defaultValue : Byte.parseByte(val);
 }

 public Configuration() {
  InputStream in = ClassLoader.getSystemClassLoader().getResourceAsStream("config.xml");
  try {
   this.loadFromXML(in);
   in.close();
  } catch (IOException ioe) {

  }
 }
}

5. Test

import Model.Message;
import Utils.JedisUtil;
import Utils.ObjectUtil;
import redis.clients.jedis.Jedis;

import java.io.IOException;

/**
 * Created by Kinglf on 2016/10/17.
 */
public class TestRedisQueue {
 public static byte[] redisKey = "key".getBytes();
 static {
  try {
   init();
  } catch (IOException e) {
   e.printStackTrace();
  }
 }

 private static void init() throws IOException {
  for (int i = 0; i < 1000000; i++) {
   Message message = new Message(i, "这是第" + i + "个内容");
   JedisUtil.lpush(redisKey, ObjectUtil.object2Bytes(message));
  }

 }

 public static void main(String[] args) {
  try {
   pop();
  } catch (Exception e) {
   e.printStackTrace();
  }
 }

 private static void pop() throws Exception {
  byte[] bytes = JedisUtil.rpop(redisKey);
  Message msg = (Message) ObjectUtil.bytes2Object(bytes);
  if (msg != null) {
   System.out.println(msg.getId() + "----" + msg.getContent());
  }
 }
}

每执行一次pop()方法,结果如下:
<br>1----这是第1个内容
<br>2----这是第2个内容
<br>3----这是第3个内容
<br>4----这是第4个内容

Summary

At this point, the producer and consumer code of the entire Redis message queue has been completed

1 .Message The entity class that needs to be transmitted (needs to implement the Serializable interface)

2.Configuration Redis configuration reading class, inherited from Properties

3.ObjectUtil combines the object and Tool class for bidirectional conversion of byte arrays

4.Jedis is a tool class that uses the first-in-first-out (FIFO) characteristics of the message queue and combines the push and pop operations in the Redis list

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