使用Java8的函数式接口简化代码

前言

因为这段时间使用SpringBoot的缘由，不少东西都用了SpringBoot内部的Template来作，也没关心底层怎么操做的。最近忙里偷闲回答了几个问题，正巧看到一个关于Redis资源释放问题的，引发了个人兴趣，便去看了下官方文档。
Redis推荐的Java客户端是jedis，关于Jedis的配置那些我就不说了，直接上他的示例代码

You use it by:

/// Jedis implements Closeable. Hence, the jedis instance will be auto-closed after the last statement.
try (Jedis jedis = pool.getResource()) {
  /// ... do stuff here ... for example
  jedis.set("foo", "bar");
  String foobar = jedis.get("foo");
  jedis.zadd("sose", 0, "car"); jedis.zadd("sose", 0, "bike"); 
  Set<String> sose = jedis.zrange("sose", 0, -1);
}
/// ... when closing your application:
pool.destroy();

If you can't use try-with-resource, you can still enjoy with Jedis.close().

Jedis jedis = null;
try {
  jedis = pool.getResource();
  /// ... do stuff here ... for example
  jedis.set("foo", "bar");
  String foobar = jedis.get("foo");
  jedis.zadd("sose", 0, "car"); jedis.zadd("sose", 0, "bike"); 
  Set<String> sose = jedis.zrange("sose", 0, -1);
} finally {
  // You have to close jedis object. If you don't close then
  // it doesn't release back to pool and you can't get a new
  // resource from pool.
  if (jedis != null) {
    jedis.close();
  }
}
/// ... when closing your application:
pool.destroy();

If Jedis was borrowed from pool, it will be returned to pool with
proper method since it already determines there was
JedisConnectionException occurred. If Jedis wasn't borrowed from pool,
it will be disconnected and closed.

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也就是说要么用Java7的try-with-resource关闭资源，要么就try finally。
唉，又该有人吐槽Java又臭又长了，像老太婆的裹脚布同样。
怎么办呢？
咱们能够写一个方法把全部的redis操做包装起来，里面加上资源释放。
呃?工程量好像有点大，并且没逼格。。。
想啊想啊想，能不能在执行Jedis方法的时候加上咱们的代码呢？好比在以前获取链接池中的实例，在以后释放资源。
咦，好像aop能够实现啊。
可是我就想用Java8的Lambda装装逼。

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首先，咱们看下这个Java内置的函数式接口中的apply方法，解释为“将给定的参数应用于该函数”。

能够，正是咱们须要的。
开始愉快的编码吧。

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第一步：

建立一个Maven工程，指定编译版本和运行版本为jdk1.8，加入jedis依赖。

第二步：

编写Jedis配置类。

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

public class RedisConf {

    private static JedisPool pool;

    private RedisConf(){}

    static {
        pool = new JedisPool(new JedisPoolConfig(), "192.168.100.15",6379,60000,"密码手动打码",13);
    }

    public static JedisPool getJedisPool() {
        return pool;
    }
}

第三步：

编写执行器

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import java.util.function.Function;

public class RedisActuator {

    private JedisPool jedisPool = RedisConf.getJedisPool();

    public  <R> R execute(Function<Jedis, R> fun) {
        try (Jedis jedis = jedisPool.getResource()){
            return fun.apply(jedis);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
}

第四步：

编写测试代码(Jedis官方文档中的示例代码)

import com.fanxian.redis.RedisActuator;
import java.util.Set;

public class App {
    public static void main( String[] args ) {

        RedisActuator redisActuator = new RedisActuator();

        redisActuator.execute(jedis -> jedis.set("foo", "bar"));

        String foobar = redisActuator.execute(jedis -> jedis.get("foo"));

        System.out.println(foobar);

        redisActuator.execute(jedis -> jedis.zadd("sose", 0, "car"));

        redisActuator.execute(jedis -> jedis.zadd("sose", 0, "bike"));

        Set<String> sose = redisActuator.execute(jedis -> jedis.zrange("sose", 0, -1));

        System.out.println(sose);
    }
}

好像代码也没简化多少。

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本文代码:( 装了逼赶忙逃。