RedisUtil工具类封装

Redis有很多数据结构：string、hash、list、set等，但是在实际来发中，我们往往保存的是对象在redis中，所以键值对更加常用。

Redis在保存对象时，需要满足序列化，由于java的原生序列化方式效率较低，故更加常用的是Protostuff这个序列化框架。

一、封装Protostuff工具类

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import com.dyuproject.protostuff.LinkedBuffer;
import com.dyuproject.protostuff.ProtobufIOUtil;
import com.dyuproject.protostuff.Schema;
import com.dyuproject.protostuff.runtime.RuntimeSchema;

public class SerializeUtil {
    private static Map, Schema> cachedSchema = new ConcurrentHashMap<>();

    @SuppressWarnings("unchecked")
    public static  byte[] serializer(T obj) {
        Class clazz = (Class) obj.getClass();
        Schema schema = getSchema(clazz);
        return ProtobufIOUtil.toByteArray(obj, schema, LinkedBuffer.allocate(256));
    }

    public static  T deSerializer(byte[] bytes, Class clazz) {
        T message;
        try {
            message = clazz.newInstance();
        } catch (InstantiationException | IllegalAccessException e) {
            throw new RuntimeException(e);
        }
        Schema schema = getSchema(clazz);
        ProtobufIOUtil.mergeFrom(bytes, message, schema);
        return message;
    }

    @SuppressWarnings("unchecked")
    public static  Schema getSchema(Class clazz) {
        Schema schema = (Schema) cachedSchema.get(clazz);
        if (schema == null) {
            schema = RuntimeSchema.createFrom(clazz);
            if (schema != null) {
                cachedSchema.put(clazz, schema);
            }
        }
        return schema;
    }
}

二、封装RedisUtil工具类

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;

public class RedisUtil {

    private static String ADDR = "localhost";
    private static int PORT = 6379;
    private static String AUTH = "123456";

    // 最大连接实例数，默认为8，-1表示无限制，如果pool已经分配了超过max_active个jedis实例，则此时pool为耗尽
    private static int MAX_ACTIVE = 1024;

    // 最大空闲实例，默认为8
    private static int MAX_IDLE = 200;

    // 最大等待连接时间，单位毫秒默认为-1，表示永不超时，超时会抛出JedisConnectionException
    private static int MAX_WAIT = 10 * 1000;

    private static int TIMEOUT = 10 * 1000;

    // 在borrow一个jedis实例时，是否提前进行validate操作，如果为true，则得到的jedis实例均是可用的
    private static boolean TEST_ON_BORROW = true;

    private static JedisPool jedisPool = null;
    /**
     * 初始化连接池
     */
    static {
        JedisPoolConfig config = new JedisPoolConfig();
        config.setMaxTotal(MAX_ACTIVE);
        config.setMaxIdle(MAX_IDLE);
        config.setMaxWaitMillis(MAX_WAIT);
        config.setTestOnBorrow(TEST_ON_BORROW);
        jedisPool = new JedisPool(config, ADDR, PORT, TIMEOUT, AUTH);
    }

    /**
     * 获取jedis实例
     */
    public synchronized static Jedis getJedis() {
        if (jedisPool != null) {

            Jedis resource = jedisPool.getResource();
            return resource;
        }
        return null;
    }

    /**
     * 释放资源
     * 
     * @param jedis
     */
    public static void close(final Jedis jedis) {
        if (jedis != null) {
            jedis.close();
        }
    }

    /**
     * 保存对象（键-值）
     * 
     * @param 
     * 
     * @param key
     * @param object
     * @return
     */
    public static  String setObject(String key, T object) {
        Jedis jedis = getJedis();
        try {
            return jedis.set(key.getBytes(), SerializeUtil.serializer(object));
        } catch (Exception e) {
            throw new RuntimeException(e.getMessage(), e);
        } finally {
            close(jedis);
        }
    }

    /**
     * 带时间保存（键值）
     * 
     * @param key
     * @param object
     * @param expiretime
     * @return
     */
    public static  String setObject(String key, T object, long expiretime) {
        Jedis jedis = null;
        try {
            jedis = getJedis();
            return jedis.psetex(key.getBytes(), expiretime, SerializeUtil.serializer(object));
        } catch (Exception e) {
            throw new RuntimeException(e.getMessage(), e);
        } finally {
            close(jedis);
        }
    }

    /**
     * 读取对象（键-值）
     * 
     * @param key
     * @param clazz
     * @return
     */
    public static  T getObject(String key, Class clazz) {
        Jedis jedis = getJedis();
        try {
            byte[] bytes = jedis.get(key.getBytes());
            T object = SerializeUtil.deSerializer(bytes, clazz);
            return object;
        } catch (Exception e) {
            throw new RuntimeException(e.getMessage(), e);
        } finally {
            close(jedis);
        }
    }

    /**
     * 删除key
     */
    public static Long deleteObject(String key) {
        Jedis jedis = null;
        try {
            jedis = getJedis();
            return jedis.del(key.getBytes());
        } catch (Exception e) {
            return null;
        } finally {
            close(jedis);
        }
    }

    /**
     * 检查存在
     * 
     * @param key
     * @return
     */
    public static Boolean existsObject(String key) {
        Jedis jedis = null;
        try {
            jedis = getJedis();
            return jedis.exists(key.getBytes());
        } catch (Exception e) {
            throw new RuntimeException(e.getMessage(), e);
        } finally {
            close(jedis);
        }
    }

}

三、测试

User：

public class User{

    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;
    }

    @Override
    public String toString() {
        return "User [name=" + name + ", age=" + age + "]";
    }

}

Main：

public class Main {
    public static void main(String[] args) {
        User user = new User();
        user.setName("旭旭宝宝");
        user.setAge(33);
        RedisUtil.setObject("user", user);
        User obj = RedisUtil.getObject("user", User.class);
        System.out.println(obj);
        System.out.println(RedisUtil.existsObject("user"));
    }
}

测试结果：

对于序列化的详解，参照：
https://blog.csdn.net/qq_35890572/article/details/81630052