RedisEclipse
阅读原文时间:2023年07月08日阅读:1

1.Eclipse配置

2.HelloWorld

import redis.clients.jedis.Jedis;

public class TestPing {

public static void main(String[] args) {

Jedis jedis = new Jedis("127.0.0.1",6379);

System.out.println(jedis.ping());

}

}

3.Jedis常见操作

import java.util.Set;

import redis.clients.jedis.Jedis;

public class TestAPI {

public static void main(String[] args) {

Jedis jedis = new Jedis("127.0.0.1",6379);

jedis.set("k1", "v1");

jedis.set("k2", "v2");

jedis.set("k3", "v3");

System.out.println(jedis.get("k1"));

Set sets = jedis.keys("*");

System.out.println(sets.toString());

System.out.println(sets.size());

}

}

4.Redis主从复制

import redis.clients.jedis.Jedis;

public class TestMS {

public static void main(String[] args) {

Jedis jedisM = new Jedis("127.0.0.1",6379);

Jedis jedisS = new Jedis("127.0.0.1",6380);

jedisS.slaveof("127.0.0.1",6379);

jedisM.set("k1", "v1");

System.out.println(jedisS.get("k1"));

}

}

5.Redis事务

import javax.swing.plaf.basic.BasicTreeUI.TreeCancelEditingAction;

import redis.clients.jedis.Jedis;

import redis.clients.jedis.Transaction;

public class TestTX {

public boolean transMethod() throws InterruptedException {

Jedis jedis = new Jedis("127.0.0.1", 6379);

int balance;// 可用余额

int debt;// 欠额

int amtToSubtract = 10;// 实刷额度

jedis.watch("balance");

//     jedis.set("balance","5");//此句不该出现,讲课方便。模拟其他程序已经修改了该条目

Thread.sleep(7000);

balance = Integer.parseInt(jedis.get("balance"));

if (balance < amtToSubtract) {

jedis.unwatch();

System.out.println("modify");

return false;

} else {

System.out.println("***********transaction");

Transaction transaction = jedis.multi();

transaction.decrBy("balance", amtToSubtract);

transaction.incrBy("debt", amtToSubtract);

transaction.exec();

balance = Integer.parseInt(jedis.get("balance"));

debt = Integer.parseInt(jedis.get("debt"));

System.out.println("*******" + balance);

System.out.println("*******" + debt);

return true;

}

}

/**

* 通俗点讲,watch命令就是标记一个键,如果标记了一个键, 在提交事务前如果该键被别人修改过,那事务就会失败,这种情况通常可以在程序中

* 重新再尝试一次。

* 首先标记了键balance,然后检查余额是否足够,不足就取消标记,并不做扣减; 足够的话,就启动事务进行更新操作,

* 如果在此期间键balance被其它人修改, 那在提交事务(执行exec)时就会报错, 程序中通常可以捕获这类错误再重新执行一次,直到成功。

* @throws InterruptedException

*/

public static void main(String[] args) throws InterruptedException {

TestTX test = new TestTX();

boolean retValue = test.transMethod();

System.out.println("main retValue-------: " + retValue);

}

}

6.Redis线程池

import redis.clients.jedis.Jedis;

import redis.clients.jedis.JedisPool;

import redis.clients.jedis.JedisPoolConfig;

public class JedisPoolUtil {

private static volatile JedisPool jedisPool = null;

private JedisPoolUtil(){}

public static JedisPool getJedisPoolUtil(){

if(null==jedisPool){

synchronized(JedisPoolUtil.class){

if(null==jedisPool){

JedisPoolConfig poolConfig = new JedisPoolConfig();

poolConfig.setMaxActive(1000);

poolConfig.setMaxIdle(32);

poolConfig.setMaxWait(100*1000);

poolConfig.setTestOnBorrow(true);

jedisPool = new JedisPool(poolConfig,"127.0.0.1",6379);

}

}

}

return jedisPool;

}

public static void release(JedisPool jedisPool,Jedis jedis){

if(null!=jedis){

jedisPool.returnResourceObject(jedis);

}

}

}

import redis.clients.jedis.Jedis;

import redis.clients.jedis.JedisPool;

public class TEstPool {

public static void main(String[] args) {

JedisPool jedisPool = JedisPoolUtil.getJedisPoolUtil();

Jedis jedis = null;

try{

jedis = jedisPool.getResource();

jedis.set("aa", "bb");

}catch(Exception e){

e.printStackTrace();

}finally{

JedisPoolUtil.release(jedisPool, jedis);

}

}

}

7.RedisPool配置

JedisPool的配置参数大部分是由JedisPoolConfig的对应项来赋值的。

maxActive:控制一个pool可分配多少个jedis实例,通过pool.getResource()来获取;如果赋值为-1,则表示不限制;如果pool已经分配了maxActive个jedis实例,则此时pool的状态为exhausted。

maxIdle:控制一个pool最多有多少个状态为idle(空闲)的jedis实例;

whenExhaustedAction:表示当pool中的jedis实例都被allocated完时,pool要采取的操作;默认有三种。

WHEN_EXHAUSTED_FAIL --> 表示无jedis实例时,直接抛出NoSuchElementException;

WHEN_EXHAUSTED_BLOCK --> 则表示阻塞住,或者达到maxWait时抛出JedisConnectionException;

WHEN_EXHAUSTED_GROW --> 则表示新建一个jedis实例,也就说设置的maxActive无用;

maxWait:表示当borrow一个jedis实例时,最大的等待时间,如果超过等待时间,则直接抛JedisConnectionException;

testOnBorrow:获得一个jedis实例的时候是否检查连接可用性(ping());如果为true,则得到的jedis实例均是可用的;

testOnReturn:return 一个jedis实例给pool时,是否检查连接可用性(ping());

testWhileIdle:如果为true,表示有一个idle object evitor线程对idle object进行扫描,如果validate失败,此object会被从pool中drop掉;这一项只有在timeBetweenEvictionRunsMillis大于0时才有意义;

timeBetweenEvictionRunsMillis:表示idle object evitor两次扫描之间要sleep的毫秒数;

numTestsPerEvictionRun:表示idle object evitor每次扫描的最多的对象数;

minEvictableIdleTimeMillis:表示一个对象至少停留在idle状态的最短时间,然后才能被idle object evitor扫描并驱逐;这一项只有在timeBetweenEvictionRunsMillis大于0时才有意义;

softMinEvictableIdleTimeMillis:在minEvictableIdleTimeMillis基础上,加入了至少minIdle个对象已经在pool里面了。如果为-1,evicted不会根据idle time驱逐任何对象。如果minEvictableIdleTimeMillis>0,则此项设置无意义,且只有在timeBetweenEvictionRunsMillis大于0时才有意义;

lifo:borrowObject返回对象时,是采用DEFAULT_LIFO(last in first out,即类似cache的最频繁使用队列),如果为False,则表示FIFO队列;

==================================================================================================================

其中JedisPoolConfig对一些参数的默认设置如下:

testWhileIdle=true

minEvictableIdleTimeMills=60000

timeBetweenEvictionRunsMillis=30000

numTestsPerEvictionRun=-1