spring boot开发web api应用实践（五）集成Redis客户端

    本篇主要记录如何在spring boot开发中，集成redis操作。按照spring boot的惯例，开发一个redis starter模块，借此记录如何开发一个spring boot starter模块。

     在java ide中新建maven工程，按照spring boot starter约定的规则命名为ecode-redis-spring-boot-starter，并引入依赖：

  <dependencies>
      <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-autoconfigure</artifactId>
      </dependency>
      <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-configuration-processor</artifactId>
           <optional>true</optional>
      </dependency>
      <dependency>
      	  <groupId>redis.clients</groupId>
      	  <artifactId>jedis</artifactId>
      </dependency>
      <dependency>
          <groupId>org.slf4j</groupId>
          <artifactId>slf4j-api</artifactId> 
	  </dependency>
  </dependencies>
  <dependencyManagement>
        <dependencies>
            <dependency>
                <!-- Import dependency management from Spring Boot,not include plugin
                    management as the parent import style -->
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
  </dependencyManagement>

 完整的pom.xml参考源码文件。工程结构如下图：

     本redis-starter模块主要java文件只有三个：

     （1）redis连接池配置类：RedisProperties.java

        redis连接池的配置项主要有（下面配置项主要配置在application.properties中）：             

ecode.redis.host=redis服务端主机地址(如192.168.1.110)
ecode.redis.port=redis服务连接端口(默认6379)
ecode.redis.timeout=3000
ecode.redis.password=redis_password
ecode.redis.max-active=50
ecode.redis.max-idle=5
ecode.redis.min-idle=0
ecode.redis.max-waitMillis=5000
ecode.redis.test-on-borrow=false
ecode.redis.test-on-return=false
ecode.redis.dbidx=0

   对应的java配置类为RedisProperties.java，代码片段：

import org.springframework.boot.context.properties.ConfigurationProperties;
 
@ConfigurationProperties(prefix = "ecode.redis")
public class RedisProperties {
    private String host;
    private int port = 6379;
    private int timeout = 3000;
    private String password;
    private int maxActive = 10;
    private int maxIdle = 5;
    private int minIdle = 0;
    private long maxWaitMillis = 5000;
    private boolean testOnBorrow = false;
    private boolean testOnReturn = false;
    private int dbidx;

   //属性字段对应的set、get方法
｝

    @ConfigurationProperties注解指定该类为spring boot的属性配置类，prefix属性指定配置项的前缀。

   （2）redis连接池自动初始化类：RedisAutoConfiguration.java

import javax.annotation.PostConstruct;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.util.Assert;

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;

@Configuration
@EnableConfigurationProperties(RedisProperties.class)
@ConditionalOnClass({ JedisPoolConfig.class, JedisPool.class, Jedis.class })
public class RedisAutoConfiguration {
    @Autowired
    private RedisProperties properties;
    
    private JedisPool jedisPool;
    
    @PostConstruct
    public void initJedisPool() {
        System.out.print("------初始化JedisPool.....host=" + properties.getHost());
        boolean hostExist = properties.getHost() != null && properties.getHost().trim().length() > 0;
        Assert.isTrue(hostExist, "Redis主机地址不能为空，请配置[ecode.redis.host]");
        
        JedisPoolConfig config = new JedisPoolConfig();
        config.setMaxTotal(properties.getMaxActive());
        config.setMaxIdle(properties.getMaxIdle());
        config.setMinIdle(properties.getMinIdle());
        config.setMaxWaitMillis(properties.getMaxWaitMillis());
        config.setTestOnBorrow(properties.isTestOnBorrow());
        config.setTestOnReturn(properties.isTestOnReturn()); 
        
        if (properties.getPassword() == null || properties.getPassword().trim().length() <= 0){
            jedisPool = new JedisPool(config, properties.getHost(), properties.getPort(), 
                                        properties.getTimeout(), null, properties.getDbidx());
        }else{
            jedisPool = new JedisPool(config, properties.getHost(), properties.getPort(), properties.getTimeout(), 
                                        properties.getPassword(), properties.getDbidx());
        }
        
        System.out.println(".....ok!");
    }

    //........初始化redis操作客户端实例并注入spring容器
}

   （3）redis命令操作类：RedisClient.java

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPubSub;
import redis.clients.jedis.Pipeline;
import redis.clients.jedis.Response;

public class RedisClient {
    private JedisPool pool;

    public void setPool(JedisPool pool){ this.pool = pool; }
    
    public RedisClient(){}
    public RedisClient(JedisPool pool){ this.pool = pool;}
    
    public Jedis getJedis() { return pool.getResource(); }
    
    public void release(Jedis jedis) {  if (jedis != null) jedis.close(); }
    
    public Set<String> getAllKeys(String pattern){
        Jedis jedis = null;  
        try {  
            jedis = getJedis();  
            return jedis.keys(pattern);
        } catch (Exception e) {
            String err = "从Redis里获取所有匹配("+pattern+")的KEY值发生异常";
            //LOG.error(err, e);
            throw new RuntimeException(err, e);
        }finally{
            release(jedis);
        }
    }
    
    /**
     * 以秒为单位返回 key的剩余过期时间。<br><br>
     * 注：当 key不存在时，返回 -2 。 当 key存在但没有设置剩余生存时间时，返回 -1 。 否则，以秒为单位，返回 key的剩余生存时间。<br>
     *    在 Redis 2.8 以前，当 key 不存在，或者 key 没有设置剩余生存时间时，命令都返回 -1 
     * @param key
     * @return 
     * 
     */
    public Long ttl(String key) { 
        Jedis jedis = null;  
        try {  
            jedis = getJedis();  
            return jedis.ttl(key);
        } catch (Exception e) {
            String err = "从Redis里获取key="+key+"的剩余过期时长发生异常";
            //LOG.error(err, e);
            throw new RuntimeException(err, e);
        }finally{
            release(jedis);
        }
    }
    
    public void set(String key, String value) {  
        if (value == null){
            return;
        }
        
        Jedis jedis = null;  
        try {  
            jedis = getJedis();  
            jedis.set(key, value);
        } catch (Exception e) {
            //LOG.error("往Redis里set[key={}, value={}]的值发生异常", key, value, e);
            throw new RuntimeException("往Redis里设置key="+key+"的值发生异常", e);
        }finally{
            release(jedis);
        }
    }

   //....其他redis命令操作

}

   

    然后在第(2)步的redis连接池自动初始化类（RedisAutoConfiguration.java）中增加RedisClient的初始化方法：

    @Bean
    @ConditionalOnMissingBean
    public RedisClient redisClient(){
        Assert.isTrue(jedisPool != null, "JedisPool尚未初始化，无法初始化RedisClient");
        return new RedisClient(jedisPool);
    }

   代码完成后，要使项目运行时，redis连接池自动初始化类（RedisAutoConfiguration.java）生效，也就是真正做到redis的auto configure，还需要在spring.factories文件中注册RedisAutoConfiguration.java，该文件位于resources/META-INF路径下面。注册内容如下：

org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.jsecode.springboot.redis.RedisAutoConfiguration

 很多道友初次创建自己的spring boot starter模块时，发现配置类并没有auto configure，原因就是忘了在spring.factories文件中注册自己的AutoConfiguration类。

（4）在应用中使用redis客户端，只需要在应用的pom.xml中引入ecode-redis-spring-boot-starter模块的依赖，然后在需要使用redis的类中注入RedisClient的实例：

      @Autowired
      RedisClient redisClient;

 然后调用redisClient来操作redis命令。

完整工程源码参考github