Redis Java客户端Jredis

﹏ヽ暗。殇╰゛Y 2022-08-07 12:35 191阅读 0赞

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][https_github.com_alphazero_jredis]

![Center][]

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("192.168.36.189", 6379);
    		//jredis.auth(password);
    		try {
    			jredis.ping();
    			//是否通
    			//清空数据库
    			jredis.flushdb();
    		} catch (RedisException e) {
    			e.printStackTrace();
    		}
    		jredis.set("key", "abc");
    		if(jredis.exists("key")){  
    		   System.out.println(new String(jredis.get("key")));
    		}  
    		
    		//保存单个对象
    		User user = new User();
    		user.setBirthDate(new Date());
    		user.setName("jack");
    		jredis.set("user", user);
    		System.out.println(DefaultCodec.decode(jredis.get("user")));
    		//集合
    		jredis.sadd("userList", user);
    		user = new User();
    		user.setBirthDate(new Date());
    		user.setName("lucy");
    		jredis.sadd("userList", user);
    		System.out.println(DefaultCodec.decode(jredis.smembers("userList")));
    		
    		//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("192.168.36.189", 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("key", "abc");
    		 System.out.println(new String(jredis.get("key")));
    		 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("192.168.36.189", 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("key", "abc");
    		if(jredis.exists("key")){  
    		   System.out.println(new String(jredis.get("key")));
    		}  
    		//保存单个对象
    		User user = new User();
    		user.setBirthDate(new Date());
    		user.setName("jack");
    		jredis.set("user", user);
    		System.out.println(DefaultCodec.decode(jredis.get("user")));
    		//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("192.168.36.189", 6379, 0, null);
    		ConnectionSpec connectionSpec2 = DefaultConnectionSpec.newSpec("192.168.36.54", 6379, 0, null);
    		serverPools.put("1", connectionSpec1);
    		serverPools.put("2", connectionSpec2);
    	}
    
    	private String next() {
    		if (current > serverPools.size()) {
    			current = 1;
    		}
    		int nextIndex = current;
    		current++;
    		return nextIndex + "";
    	}
    
    	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("1");
    		}
    
    		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("key"));
    		try {
    			Thread.sleep(1000);
    		} catch (InterruptedException e) {
    			e.printStackTrace();
    		}
    		System.out.println(redis.getS("key"));
    		try {
    			Thread.sleep(3000);
    		} catch (InterruptedException e) {
    			e.printStackTrace();
    		}
    		System.out.println(redis.getS("key"));
    	}
    }

参考： [http://dmouse.iteye.com/blog/813026][http_dmouse.iteye.com_blog_813026]

4.与spring集成，参考：[http://blog.csdn.net/zhu\_tianwei/article/details/44900219][http_blog.csdn.net_zhu_tianwei_article_details_44900219]

[https_github.com_alphazero_jredis]: https://github.com/alphazero/jredis
[Center]: /images/20220805/d0f5a194fd40456e86fa6f3198f07d99.png
[http_dmouse.iteye.com_blog_813026]: http://dmouse.iteye.com/blog/813026
[http_blog.csdn.net_zhu_tianwei_article_details_44900219]: http://blog.csdn.net/zhu_tianwei/article/details/44900219