Redis Java客户端Jredis

xiuxuan

JRedis 是一个高性能的 Java 客户端，用来连接到Redis分布式哈希键-值数据库。提供同步和异步的连接。

　　项目地址：https://github.com/alphazero/jredis
　　


　　由于jreds的jar包不在公网的maven仓库中，所以需要下载源码使用如下命令，将jar添加到本地maven仓库中。
　　cd jredis-master\core
　　mvn -Dmaven.test.skip=true install
　　在工程pom.xml中添加依赖：
　　<dependency>
<groupId>org.jredis</groupId>
<artifactId>jredis-core-all</artifactId>
<version>a.0-SNAPSHOT</version>
</dependency>1.简单实例
　　package cn.slimsmart.redis.demo.jredis;
import java.util.Date;
import org.jredis.JRedis;
import org.jredis.RedisException;
import org.jredis.ri.alphazero.JRedisClient;
import org.jredis.ri.alphazero.support.DefaultCodec;
public class JredisTest {
public static void main(String[] args) throws Exception {
JRedis jredis = new JRedisClient(&quot;192.168.36.189&quot;, 6379);
//jredis.auth(password);
try {
jredis.ping();
//是否通
//清空数据库
jredis.flushdb();
} catch (RedisException e) {
e.printStackTrace();
}
jredis.set(&quot;key&quot;, &quot;abc&quot;);
if(jredis.exists(&quot;key&quot;)){  
System.out.println(new String(jredis.get(&quot;key&quot;)));
}  
//保存单个对象
User user = new User();
user.setBirthDate(new Date());
user.setName(&quot;jack&quot;);
jredis.set(&quot;user&quot;, user);
System.out.println(DefaultCodec.decode(jredis.get(&quot;user&quot;)));
//集合
jredis.sadd(&quot;userList&quot;, user);
user = new User();
user.setBirthDate(new Date());
user.setName(&quot;lucy&quot;);
jredis.sadd(&quot;userList&quot;, user);
System.out.println(DefaultCodec.decode(jredis.smembers(&quot;userList&quot;)));
//关闭
jredis.quit();
}
}
除此之外，jredis连接redis服务器端还可以使用如下方式：
　　ConnectionSpec connectionSpec = DefaultConnectionSpec.newSpec(&quot;192.168.36.189&quot;, 6379, 0,null);
connectionSpec.setReconnectCnt(100);  
//connectionSpec.setConnectionFlag(Connection.Flag.RELIABLE, Boolean.TRUE);
//connectionSpec.setHeartbeat(2);  
connectionSpec.setMaxConnectWait(3000);
//JRedis jredis = new JRedisClient(connectionSpec);
JRedis jredis = new JRedisPipelineService(connectionSpec);
jredis.ping();
jredis.set(&quot;key&quot;, &quot;abc&quot;);
System.out.println(new String(jredis.get(&quot;key&quot;)));
jredis.quit();
　　2.连接池
　　
　　package cn.slimsmart.redis.demo.jredis;
import java.util.Date;
import org.apache.commons.pool2.impl.GenericObjectPoolConfig;
import org.jredis.JRedis;
import org.jredis.connector.ConnectionSpec;
import org.jredis.ri.alphazero.connection.DefaultConnectionSpec;
import org.jredis.ri.alphazero.support.DefaultCodec;
import org.springframework.data.redis.connection.jredis.JredisPool;
public class JredisPoolTest {
public static void main(String[] args) throws Exception {
//链接配置
ConnectionSpec connectionSpec = DefaultConnectionSpec.newSpec(&quot;192.168.36.189&quot;, 6379, 0,null);
connectionSpec.setReconnectCnt(100);  
//connectionSpec.setConnectionFlag(Connection.Flag.RELIABLE, Boolean.TRUE);
//connectionSpec.setHeartbeat(5);  
connectionSpec.setMaxConnectWait(3000);
//连接池配置
GenericObjectPoolConfig poolConfig = new GenericObjectPoolConfig();
poolConfig.setMaxTotal(10);
poolConfig.setMinIdle(2);
poolConfig.setMaxIdle(10);
poolConfig.setMaxWaitMillis(3000);
poolConfig.setTestOnBorrow(true);
poolConfig.setTestOnReturn(true);
poolConfig.setTestWhileIdle(true);
poolConfig.setTimeBetweenEvictionRunsMillis(3000);
JredisPool jredisPool = new JredisPool(connectionSpec,poolConfig);
//获取链接
JRedis jredis = jredisPool.getResource();
jredis.set(&quot;key&quot;, &quot;abc&quot;);
if(jredis.exists(&quot;key&quot;)){  
System.out.println(new String(jredis.get(&quot;key&quot;)));
}  
//保存单个对象
User user = new User();
user.setBirthDate(new Date());
user.setName(&quot;jack&quot;);
jredis.set(&quot;user&quot;, user);
System.out.println(DefaultCodec.decode(jredis.get(&quot;user&quot;)));
//回收
jredisPool.returnResource(jredis);
}
}

3.Fail tolerance



要保证一个client连接到slave服务上读取数据，如果slave down 了之后，可以在不影响应用的情况下，自动切换到另外一个可用的slave。因为jredis不支持设置多个slave服务器，所以写了一个小工具类，目的是为了探测如果的当前正在使用的slave没有heartbeat之后，立马可以切换到一个可用的slave；这样可以保证one of slave down掉之后，不用missing-load也可及时切换到另外一个slave上读数据。
　　package cn.slimsmart.redis.demo.jredis;
import java.util.HashMap;
import org.jredis.JRedis;
import org.jredis.connector.ConnectionSpec;
import org.jredis.ri.alphazero.JRedisClient;
import org.jredis.ri.alphazero.connection.DefaultConnectionSpec;
import org.jredis.ri.alphazero.support.DefaultCodec;
public class RedisFailTolerance {
private static JRedis jredis = null;
private static ConnectionSpec defaultConnectionSpec = null;
private static int current = 1;
private static HashMap<String, ConnectionSpec> serverPools = new HashMap<String, ConnectionSpec>();
static {
ConnectionSpec connectionSpec1 = DefaultConnectionSpec.newSpec(&quot;192.168.36.189&quot;, 6379, 0, null);
ConnectionSpec connectionSpec2 = DefaultConnectionSpec.newSpec(&quot;192.168.36.54&quot;, 6379, 0, null);
serverPools.put(&quot;1&quot;, connectionSpec1);
serverPools.put(&quot;2&quot;, connectionSpec2);
}
private String next() {
if (current > serverPools.size()) {
current = 1;
}
int nextIndex = current;
current++;
return nextIndex + &quot;&quot;;
}
private ConnectionSpec getConnectionSpec() {
if (defaultConnectionSpec != null) {
return defaultConnectionSpec;
}
jredis = null;
/**
* we are working multiple servers try different servers,util we fetch
* the first available server pool
*/
HashMap<String, ConnectionSpec> tryServers = new HashMap<String, ConnectionSpec>(serverPools);
if (serverPools.size() == 1) {
return (ConnectionSpec) serverPools.get(&quot;1&quot;);
}
while (!tryServers.isEmpty()) {
ConnectionSpec connectionSpec = tryServers.get(this.next());
if (isConnect(connectionSpec)) {
return connectionSpec;
}
tryServers.remove(connectionSpec);
if (tryServers.isEmpty()) {
break;
}
}
return null;
}
/**
* try whether the server is available
*
* @param connectionSpec
* @return true or false
*/
private boolean isConnect(ConnectionSpec connectionSpec) {
if (connectionSpec == null) {
return false;
}
JRedis jredis = new JRedisClient(connectionSpec.getAddress().getHostAddress(), connectionSpec.getPort());
try {
jredis.ping();
jredis.quit();
} catch (Exception e) {
return false;
}
return true;
}
public void initialize() {
defaultConnectionSpec = this.getConnectionSpec();
if (jredis == null) {
synchronized (this) {
jredis = new JRedisClient(defaultConnectionSpec);
}
}
}
public String getS(String key) {
this.initialize();
String value = null;
try {
value = DefaultCodec.toStr(jredis.get(key));
} catch (Exception e) {
e.printStackTrace();
defaultConnectionSpec = null;
this.initialize();
}
return value;
}
public static void main(String args[]) {
RedisFailTolerance redis = new RedisFailTolerance();
System.out.println(redis.getS(&quot;key&quot;));
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(redis.getS(&quot;key&quot;));
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(redis.getS(&quot;key&quot;));
}
}
参考：http://dmouse.iyunv.com/blog/813026


　　4.与spring集成，参考：http://blog.iyunv.com/zhu_tianwei/article/details/44900219