Java连接redis的客户端有很多，其中比较常用的是Jedis. (参考：redis client)
spring-data-redis则是对Jedis进行了高度封装，使用起来非常方便。下面就以代码为例说明spring-data-redis的使用。
整个项目使用maven管理jar包，pom文件如下：
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<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.snow</groupId> <artifactId>redis-test</artifactId> <version>0.0.1</version> <packaging>jar</packaging> <name>redis-test</name> <url>http://maven.apache.org</url> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <spring.version>4.3.2.RELEASE</spring.version> <slf4j.version>1.7.12</slf4j.version> <log4j.version>1.2.17</log4j.version> <junit.version>4.12</junit.version> <spring-data-redis.version>1.7.2.RELEASE</spring-data-redis.version> </properties> <dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${spring.version}</version> <scope>test</scope> </dependency> <dependency> <groupId>redis.clients</groupId> <artifactId>jedis</artifactId> <version>2.5.0</version> <type>jar</type> </dependency> <dependency> <groupId>org.springframework.data</groupId> <artifactId>spring-data-redis</artifactId> <version>${spring-data-redis.version}</version> <type>jar</type> </dependency> <!-- log --> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>${log4j.version}</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> <version>${slf4j.version}</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-api</artifactId> <version>${slf4j.version}</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>${junit.version}</version> <scope>test</scope> </dependency> </dependencies></project> |
主要用到的jia包是spring-context、spring-data-redis、jedis以及日志打印相关的三个jar包
配置spring-data-redis如下application-context-redis.xml：
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<!-- 配置方法见 //www.zzvips.com/database/201311/254449.html --><bean id="jedisPoolConfig" class="redis.clients.jedis.JedisPoolConfig"> <property name="maxTotal" value="500"/> <!-- 控制一个pool可分配多少个jedis实例 --> <property name="maxIdle" value="100"/><!-- 最大能够保持idel状态的对象数 --> <property name="maxWaitMillis" value="1000"/><!-- 表示当borrow一个jedis实例时，最大的等待时间，如果超过等待时间，则直接抛出JedisConnectionException --> <property name="timeBetweenEvictionRunsMillis" value="30000"/><!-- 多长时间检查一次连接池中空闲的连接 --> <property name="minEvictableIdleTimeMillis" value="30000"/><!-- 空闲连接多长时间后会被收回, 单位是毫秒 --> <property name="testOnBorrow" value="true"/> <!-- 当调用borrow Object方法时，是否进行有效性检查 --> <property name="testOnReturn" value="true"/> <!-- 当调用return Object方法时，是否进行有效性检查 --> <property name="testWhileIdle" value="true"/></bean> <span style="white-space:pre"> </span><!-- 直连master --><bean id="jedisConnectionFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory"> <constructor-arg ref="jedisPoolConfig" /> <property name="hostName" value="${redis.hostName}" /> <property name="port" value="${redis.port}" /> <!-- <property name="password" value ="${redis.password}" /> --></bean> <span style="white-space:pre"> </span><bean id="redisTemplate" class="org.springframework.data.redis.core.StringRedisTemplate" > <span style="white-space:pre"> </span><property name="connectionFactory" ref="jedisConnectionFactory" /> <span style="white-space:pre"> </span></bean> |
在配置文件中先配置一个连接池，然后配置一个connection工厂，最后配置bean redisTemplate，我们使用的class是StringRedisTemplate，从而决定我们后面的操作key及value都必须是String类型的。而通常我们希望将一个对象存入到redis中，这个时候可以将对象转为json字符串之后再存储，取出来的时候再将json字符串转换为对象。这种操作还是比较方便的，都有线程的jar包。除了StringRedisTemplate之外，我们还可以使用RedisTemplate类，这里暂不介绍。
在application-context-redis.xml这个配置文件中还需要用到redis的host和port信息，我们可以配置一个文件properties文件如下：redis.properties
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redis.hostName=127.0.0.1redis.port=6379 |
这个配置文件需要在application-contex.xml中加载，同时application-context.xml还需要加载application-context-redis.xml配置文件
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<bean id="dbPropertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> <property name="ignoreUnresolvablePlaceholders" value="true" /> <property name="locations"> <list> <value>classpath:redis.properties</value> </list> </property> <property name="fileEncoding" value="UTF-8" /><!-- 资源文件的编码 --></bean> <import resource="classpath:application-context-redis.xml" /> |
接下来可以写个redis操作的接口
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public interface RedisService { public void setStr(String key, String value); public String getStr(String key); public void rPushList(String key, String value); public String lPopList(String key); public void delKey(String key); } |
接口实现如下：
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@Service(value = "redisService")public class RedisServiceImpl extends AbstractRedisDao<String, String> implements RedisService { @Override public void setStr(String key, String value) { getRedisTemplate().opsForValue().set(key, value); } @Override public String getStr(String key) { return getRedisTemplate().opsForValue().get(key); } @Override public void rPushList(String key, String value) { getRedisTemplate().opsForList().rightPush(key, value); } @Override public String lPopList(String key) { return getRedisTemplate().opsForList().leftPop(key); } @Override public void delKey(String key) { getRedisTemplate().delete(key); }} |
在该实现中继承了一个AbstractRedisDao，这个主要是提供getRedisTemplate()函数，使我们能够调用在application-context-redis.xml中配置的redisTemplate bean实例
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public abstract class AbstractRedisDao<K, V> { @Autowired protected RedisTemplate<K, V> redisTemplate; // 设置redisTemplate public void setRedisTemplate(RedisTemplate<K, V> redisTemplate) { this.redisTemplate = redisTemplate; } public RedisTemplate<K, V> getRedisTemplate() { return redisTemplate; }} |
主要的程序都已经写完了，接下来可以用Junit写个单元测试对接口测试下。
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public class RedisServiceTest extends AbstractUnitTest { private static final Logger logger = LoggerFactory.getLogger(RedisServiceTest.class); @Resource private RedisService redisService; @Test public void testSetStr() { String key = "test"; String value = "valuetest"; redisService.setStr(key, value); } @Test public void testGetStr() { String key = "test"; String value = redisService.getStr(key); logger.info("The value is {}", value); } @Test public void testRPushList() { String key = "list"; for (int i = 0; i < 10; i++) { redisService.rPushList(key, String.valueOf(i)); } } @Test public void testLPopList() { String key = "list"; for(int i = 0; i < 9; i++) { String value = redisService.lPopList(key); logger.info("lpop value is {}", value); } } @Test public void testDelKey() { String key = "list"; redisService.delKey(key); } } |
在这个测试类中，为了能够运行这些测试函数，需要对所有的bean进行实例化，这个过程是在 AbstractUnitTest中实现的，代码如下：
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@RunWith(SpringJUnit4ClassRunner.class)@ContextConfiguration(locations = {"classpath:application-context.xml"})public abstract class AbstractUnitTest { private static final Logger logger = LoggerFactory.getLogger(AbstractUnitTest.class); // @Test// public void stub() {// logger.info("msg from abstract unit test, just ignore this.");// } @After public void teardown() throws InterruptedException { logger.info("unit test complete."); TimeUnit.MILLISECONDS.sleep(500);// 因为有些测试是需要异步插入操作记录的，sleep一下等待线程结束 } } |
AbstractUnitTest类可以作为测试spring的一个通用类。
主要的代码就这些了，运行下可以看到结果是没有问题的。下面我摘抄一段打印输出说明一个问题：
016-08-02 20:43:16,608 DEBUG RedisConnectionUtils:125 - Opening RedisConnection
2016-08-02 20:43:16,609 DEBUG RedisConnectionUtils:205 - Closing Redis Connection
2016-08-02 20:43:16,610 INFO RedisServiceTest:54 - lpop value is 0
2016-08-02 20:43:16,610 DEBUG RedisConnectionUtils:125 - Opening RedisConnection
2016-08-02 20:43:16,611 DEBUG RedisConnectionUtils:205 - Closing Redis Connection
2016-08-02 20:43:16,611 INFO RedisServiceTest:54 - lpop value is 1
2016-08-02 20:43:16,611 DEBUG RedisConnectionUtils:125 - Opening RedisConnection
2016-08-02 20:43:16,611 DEBUG RedisConnectionUtils:205 - Closing Redis Connection
2016-08-02 20:43:16,612 INFO RedisServiceTest:54 - lpop value is 2
2016-08-02 20:43:16,612 DEBUG RedisConnectionUtils:125 - Opening RedisConnection
2016-08-02 20:43:16,612 DEBUG RedisConnectionUtils:205 - Closing Redis Connection
2016-08-02 20:43:16,612 INFO RedisServiceTest:54 - lpop value is 3
2016-08-02 20:43:16,612 DEBUG RedisConnectionUtils:125 - Opening RedisConnection
2016-08-02 20:43:16,613 DEBUG RedisConnectionUtils:205 - Closing Redis Connection
2016-08-02 20:43:16,613 INFO RedisServiceTest:54 - lpop value is 4
2016-08-02 20:43:16,613 DEBUG RedisConnectionUtils:125 - Opening RedisConnection
2016-08-02 20:43:16,613 DEBUG RedisConnectionUtils:205 - Closing Redis Connection
2016-08-02 20:43:16,613 INFO RedisServiceTest:54 - lpop value is 5
2016-08-02 20:43:16,613 DEBUG RedisConnectionUtils:125 - Opening RedisConnection
2016-08-02 20:43:16,614 DEBUG RedisConnectionUtils:205 - Closing Redis Connection
2016-08-02 20:43:16,614 INFO RedisServiceTest:54 - lpop value is 6
2016-08-02 20:43:16,614 DEBUG RedisConnectionUtils:125 - Opening RedisConnection
2016-08-02 20:43:16,614 DEBUG RedisConnectionUtils:205 - Closing Redis Connection
2016-08-02 20:43:16,618 INFO RedisServiceTest:54 - lpop value is 7
2016-08-02 20:43:16,618 DEBUG RedisConnectionUtils:125 - Opening RedisConnection
2016-08-02 20:43:16,618 DEBUG RedisConnectionUtils:205 - Closing Redis Connection
2016-08-02 20:43:16,618 INFO RedisServiceTest:54 - lpop value is 8
2016-08-02 20:43:16,618 INFO AbstractUnitTest:34 - unit test complete.
这段输出是运行testLPopList得到的，这里面opening RedisConnection进行了9次，然后又Closing Redis Connection 9次，这是不是说每次执行redis操作都需要创建一个连接，操作完然后又关闭连接呢？实际上不是这样的，阅读源代码我们可以发现我们对redis的所有操作都是通过回调execute函数执行的，其代码如下：
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public <T> T execute(RedisCallback<T> action, boolean exposeConnection) { return execute(action, exposeConnection, false);}// execute实现如下：// org.springframework.data.redis.core.RedisTemplate<K, V> --- 最终实现public <T> T execute(RedisCallback<T> action, boolean exposeConnection, boolean pipeline) { Assert.isTrue(initialized, "template not initialized; call afterPropertiesSet() before using it"); Assert.notNull(action, "Callback object must not be null"); RedisConnectionFactory factory = getConnectionFactory(); RedisConnection conn = null; try { if (enableTransactionSupport) { // only bind resources in case of potential transaction synchronization conn = RedisConnectionUtils.bindConnection(factory, enableTransactionSupport); } else { conn = RedisConnectionUtils.getConnection(factory); } boolean existingConnection = TransactionSynchronizationManager.hasResource(factory); RedisConnection connToUse = preProcessConnection(conn, existingConnection); boolean pipelineStatus = connToUse.isPipelined(); if (pipeline && !pipelineStatus) { connToUse.openPipeline(); } RedisConnection connToExpose = (exposeConnection ? connToUse : createRedisConnectionProxy(connToUse)); T result = action.doInRedis(connToExpose); // close pipeline if (pipeline && !pipelineStatus) { connToUse.closePipeline(); } // TODO: any other connection processing? return postProcessResult(result, connToUse, existingConnection); } finally { if (!enableTransactionSupport) { RedisConnectionUtils.releaseConnection(conn, factory); } }} |
这里面每次执行action.doInRedis(connToExpose)前都要调用RedisConnectionUtils.getConnection(factory);获得一个连接，进入RedisConnnectionUtils类中，getConnection(factory)最终调用的是doGetConnection(factory, true, false, enableTranactionSupport)这个函数。这个函数我们可以看下api文档，发现实际上并不是真的创建一个新的redis连接，它只是在connectFactory中获取一个连接，也就是从连接池中取出一个连接。当然如果connectFactory没有连接可用，此时如果allowCreate=true便会创建出一个新的连接，并且加入到connectFactory中。
基本上可以确定真实的情况是spring-data-redis已经帮我们封装了连接池管理，我们只需要调用一系列操作函数即可，这给操作redis带来了极大的方便。
最后附上本文源代码：redis-test
到此这篇关于spring-data-redis连接操作redis的实现的文章就介绍到这了,更多相关spring-data-redis连接操作redis内容请搜索服务器之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持服务器之家！
原文链接：https://blog.csdn.net/wanghuiqi2008/article/details/52097381
