发布于 2018-02-01 05:24:45 | 31 次阅读 | 评论: 0 | 来源: 网友投递

这里有新鲜出炉的Redis 设计与实现(第一版),程序狗速度看过来!

Redis Key-Value数据库

Redis是一个开源的使用ANSI C语言编写、支持网络、可基于内存亦可持久化的日志型、Key-Value数据库,并提供多种语言的API。


本篇文章主要介绍了spring整合redis缓存并以注解(@Cacheable、@CachePut、@CacheEvict)形式使用,具有一定的参考价值,有兴趣的可以了解一下。

maven项目中在pom.xml中依赖2个jar包,其他的spring的jar包省略:


<dependency> 
  <groupId>redis.clients</groupId> 
  <artifactId>jedis</artifactId> 
  <version>2.8.1</version> 
</dependency> 
<dependency> 
  <groupId>org.springframework.data</groupId> 
  <artifactId>spring-data-redis</artifactId> 
  <version>1.7.2.RELEASE</version> 
</dependency> 

spring-Redis.xml中的内容:


<?xml version="1.0" encoding="UTF-8"?> 
<beans xmlns="http://www.springframework.org/schema/beans"  
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"  
  xmlns:context="http://www.springframework.org/schema/context"  
  xmlns:mvc="http://www.springframework.org/schema/mvc"  
  xmlns:cache="http://www.springframework.org/schema/cache" 
  xsi:schemaLocation="http://www.springframework.org/schema/beans   
            http://www.springframework.org/schema/beans/spring-beans-4.2.xsd   
            http://www.springframework.org/schema/context   
            http://www.springframework.org/schema/context/spring-context-4.2.xsd   
            http://www.springframework.org/schema/mvc   
            http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd 
            http://www.springframework.org/schema/cache  
            http://www.springframework.org/schema/cache/spring-cache-4.2.xsd">  
   
  <context:property-placeholder location="classpath:redis-config.properties" />  
 
  <!-- 启用缓存注解功能,这个是必须的,否则注解不会生效,另外,该注解一定要声明在spring主配置文件中才会生效 -->  
  <cache:annotation-driven cache-manager="cacheManager" />  
   
   <!-- redis 相关配置 -->  
   <bean id="poolConfig" class="redis.clients.jedis.JedisPoolConfig">  
     <property name="maxIdle" value="${redis.maxIdle}" />   
     <property name="maxWaitMillis" value="${redis.maxWait}" />  
     <property name="testOnBorrow" value="${redis.testOnBorrow}" />  
   </bean>  
 
   <bean id="JedisConnectionFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory"  
    p:host-name="${redis.host}" p:port="${redis.port}" p:password="${redis.pass}" p:pool-config-ref="poolConfig"/>  
  
   <bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate">  
     <property name="connectionFactory" ref="JedisConnectionFactory" />  
   </bean>  
   
   <!-- spring自己的缓存管理器,这里定义了缓存位置名称 ,即注解中的value -->  
   <bean id="cacheManager" class="org.springframework.cache.support.SimpleCacheManager">  
     <property name="caches">  
      <set>  
        <!-- 这里可以配置多个redis --> 
        <!-- <bean class="com.cn.util.RedisCache">  
           <property name="redisTemplate" ref="redisTemplate" />  
           <property name="name" value="default"/>  
        </bean> -->  
        <bean class="com.cn.util.RedisCache">  
           <property name="redisTemplate" ref="redisTemplate" />  
           <property name="name" value="common"/>  
           <!-- common名称要在类或方法的注解中使用 --> 
        </bean> 
      </set>  
     </property>  
   </bean>  
   
</beans>  

redis-config.properties中的内容:


# Redis settings 
# server IP 
redis.host=127.0.0.1 
# server port 
redis.port=6379 
# server pass 
redis.pass= 
# use dbIndex 
redis.database=0 
# 控制一个pool最多有多少个状态为idle(空闲的)的jedis实例 
redis.maxIdle=300 
# 表示当borrow(引入)一个jedis实例时,最大的等待时间,如果超过等待时间(毫秒),则直接抛出JedisConnectionException;  
redis.maxWait=3000 
# 在borrow一个jedis实例时,是否提前进行validate操作;如果为true,则得到的jedis实例均是可用的  
redis.testOnBorrow=true 

com.cn.util.RedisCache类中的内容:


package com.cn.util;  
import java.io.ByteArrayInputStream; 
import java.io.ByteArrayOutputStream; 
import java.io.IOException; 
import java.io.ObjectInputStream; 
import java.io.ObjectOutputStream; 
 
import org.springframework.cache.Cache; 
import org.springframework.cache.support.SimpleValueWrapper; 
import org.springframework.dao.DataAccessException; 
import org.springframework.data.redis.connection.RedisConnection; 
import org.springframework.data.redis.core.RedisCallback; 
import org.springframework.data.redis.core.RedisTemplate; 
 
public class RedisCache implements Cache{ 
 
  private RedisTemplate<String, Object> redisTemplate;  
  private String name;  
  public RedisTemplate<String, Object> getRedisTemplate() { 
    return redisTemplate;  
  } 
    
  public void setRedisTemplate(RedisTemplate<String, Object> redisTemplate) { 
    this.redisTemplate = redisTemplate;  
  } 
    
  public void setName(String name) { 
    this.name = name;  
  } 
    
  @Override  
  public String getName() { 
    // TODO Auto-generated method stub  
    return this.name;  
  } 
 
  @Override  
  public Object getNativeCache() { 
   // TODO Auto-generated method stub  
    return this.redisTemplate;  
  } 
  
  @Override  
  public ValueWrapper get(Object key) { 
   // TODO Auto-generated method stub 
   System.out.println("get key"); 
   final String keyf = key.toString(); 
   Object object = null; 
   object = redisTemplate.execute(new RedisCallback<Object>() { 
   public Object doInRedis(RedisConnection connection)  
         throws DataAccessException { 
     byte[] key = keyf.getBytes(); 
     byte[] value = connection.get(key); 
     if (value == null) { 
       return null; 
      } 
     return toObject(value); 
     } 
    }); 
    return (object != null ? new SimpleValueWrapper(object) : null); 
   } 
  
   @Override  
   public void put(Object key, Object value) { 
    // TODO Auto-generated method stub 
    System.out.println("put key"); 
    final String keyf = key.toString();  
    final Object valuef = value;  
    final long liveTime = 86400;  
    redisTemplate.execute(new RedisCallback<Long>() {  
      public Long doInRedis(RedisConnection connection)  
          throws DataAccessException {  
        byte[] keyb = keyf.getBytes();  
        byte[] valueb = toByteArray(valuef);  
        connection.set(keyb, valueb);  
        if (liveTime > 0) {  
          connection.expire(keyb, liveTime);  
         }  
        return 1L;  
       }  
     });  
   } 
 
   private byte[] toByteArray(Object obj) {  
     byte[] bytes = null;  
     ByteArrayOutputStream bos = new ByteArrayOutputStream();  
     try {  
      ObjectOutputStream oos = new ObjectOutputStream(bos);  
      oos.writeObject(obj);  
      oos.flush();  
      bytes = bos.toByteArray();  
      oos.close();  
      bos.close();  
     }catch (IOException ex) {  
        ex.printStackTrace();  
     }  
     return bytes;  
    }  
 
    private Object toObject(byte[] bytes) { 
     Object obj = null;  
      try { 
        ByteArrayInputStream bis = new ByteArrayInputStream(bytes);  
        ObjectInputStream ois = new ObjectInputStream(bis);  
        obj = ois.readObject();  
        ois.close();  
        bis.close();  
      } catch (IOException ex) {  
        ex.printStackTrace();  
      } catch (ClassNotFoundException ex) {  
        ex.printStackTrace();  
      }  
      return obj;  
    } 
  
    @Override  
    public void evict(Object key) {  
     // TODO Auto-generated method stub  
     System.out.println("del key"); 
     final String keyf = key.toString();  
     redisTemplate.execute(new RedisCallback<Long>() {  
     public Long doInRedis(RedisConnection connection)  
          throws DataAccessException {  
       return connection.del(keyf.getBytes());  
      }  
     });  
    } 
  
    @Override  
    public void clear() {  
      // TODO Auto-generated method stub  
      System.out.println("clear key"); 
      redisTemplate.execute(new RedisCallback<String>() {  
        public String doInRedis(RedisConnection connection)  
            throws DataAccessException {  
         connection.flushDb();  
          return "ok";  
        }  
      });  
    } 
 
    @Override 
    public <T> T get(Object key, Class<T> type) { 
      // TODO Auto-generated method stub 
      return null; 
    } 
   
    @Override 
    public ValueWrapper putIfAbsent(Object key, Object value) { 
      // TODO Auto-generated method stub 
      return null; 
    } 
 
} 

到了这一步,大部分人会想在web.xml的启动配置文件地方(context-param)加入了spring-redis.xml,让项目启动时加载这个配置文件吧,但是这样启动后注解不生效。

正确的做法是:web.xml中配置了servlet控制器:


<servlet> 
 <servlet-name>SpringMVC</servlet-name> 
 <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> 
 <init-param> 
  <param-name>contextConfigLocation</param-name> 
  <param-value>/WEB-INF/spring-mvc.xml</param-value> 
 </init-param> 
 <load-on-startup>1</load-on-startup> 
 <async-supported>true</async-supported> 
</servlet> 

在DispatcherServlet的初始化过程中,框架会在web应用的 WEB-INF文件夹下寻找名为spring-mvc.xml的配置文件,如果不指定的话,默认是applicationContext.xml

只需要在spring-mvc.xml文件中引入spring-redis配置文件即可,正如spring-redis.xml中的启用注解说的:<cache:annotation-driven cache-manager="cacheManager" />注解一定要声明在spring主配置文件中才会生效。

spring-mvc.xml内容,省略了spring与spring MVC整合的那部分:


<?xml version="1.0" encoding="UTF-8"?> 
<beans xmlns="http://www.springframework.org/schema/beans"  
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"  
  xmlns:context="http://www.springframework.org/schema/context"  
  xmlns:mvc="http://www.springframework.org/schema/mvc"  
  xsi:schemaLocation="http://www.springframework.org/schema/beans   
            http://www.springframework.org/schema/beans/spring-beans-4.2.xsd   
            http://www.springframework.org/schema/context   
            http://www.springframework.org/schema/context/spring-context-4.2.xsd   
            http://www.springframework.org/schema/mvc   
            http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd"> 
  <!-- 自动扫描该包,使SpringMVC认为包下用了@controller注解的类是控制器 -->  
  <context:component-scan base-package="com.cn" />  
   
  <!-- 引入同文件夹下的redis属性配置文件 --> 
  <import resource="spring-redis.xml"/> 
   
</beans>  

在service的实现类中:


@Service 
public class UserServiceImpl implements UserService{ 
 
  @Autowired 
  private UserBo userBo; 
 
  @Cacheable(value="common",key="'id_'+#id") 
  public User selectByPrimaryKey(Integer id) { 
    return userBo.selectByPrimaryKey(id); 
  } 
   
  @CachePut(value="common",key="#user.getUserName()") 
  public void insertSelective(User user) { 
    userBo.insertSelective(user); 
  } 
 
  @CacheEvict(value="common",key="'id_'+#id") 
  public void deleteByPrimaryKey(Integer id) { 
    userBo.deleteByPrimaryKey(id); 
  } 
}

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持PHPERZ。



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