Jedis客户端已经比较易用了，不过在spring环境下，可能还需要简单的封装一下。
一、单节点Redis服务使用
即只有一个Redis server，或者在M-S模式下，只有Master提供读写服务时使用，配置中指定Master的IP和Port即可。此处使用了Spring FactoryBean方式来创建JedisPool实例。
1、SingletonClientFactoryBean.java
public class SingletonClientFactoryBean implements FactoryBean,InitializingBean {
private JedisPool jedisPool;
private int maxTotal = 128;
//最大空闲连接数
private int maxIdle = 2;
//最小空闲连接数
private int minIdle = 1;
//如果连接池耗尽，最大阻塞的时间，默认为6秒
private long maxWait = 6000;//单位毫秒
private String host;
private int port;
private int database = 0;//选择数据库，默认为0
private int timeout = 3000;//connectionTimeout，soTimeout，默认为30秒
private boolean testOnBorrow = true;
private boolean testOnReturn = true;
private String password;
public void setMaxTotal(int maxTotal) {
this.maxTotal = maxTotal;
}
public void setMaxIdle(int maxIdle) {
this.maxIdle = maxIdle;
}
public void setMinIdle(int minIdle) {
this.minIdle = minIdle;
}
public void setMaxWait(long maxWait) {
this.maxWait = maxWait;
}
public void setHost(String host) {
this.host = host;
}
public void setPort(int port) {
this.port = port;
}
public void setDatabase(int database) {
this.database = database;
}
public void setTimeout(int timeout) {
this.timeout = timeout;
}
public void setTestOnBorrow(boolean testOnBorrow) {
this.testOnBorrow = testOnBorrow;
}
public void setTestOnReturn(boolean testOnReturn) {
this.testOnReturn = testOnReturn;
}
public void setPassword(String password) {
this.password = password;
}
protected JedisPoolConfig buildConfig() {
JedisPoolConfig config = new JedisPoolConfig();
config.setMinIdle(minIdle);
config.setMaxIdle(maxIdle);
config.setMaxTotal(maxTotal);
config.setTestOnBorrow(testOnBorrow);
config.setTestOnReturn(testOnReturn);
config.setBlockWhenExhausted(true);
config.setMaxWaitMillis(maxWait);
config.setFairness(false);
return config;
}
@Override
public void afterPropertiesSet() throws Exception {
JedisPoolConfig config = buildConfig();
jedisPool = new JedisPool(config,host,port,timeout, password, database,null);
}
@Override
public JedisPool getObject() throws Exception {
return jedisPool;
}
@Override
public Class getObjectType() {
return JedisPool.class;
}
@Override
public boolean isSingleton() {
return true;
}
}
2、Spring.xml配置
3、客户端使用
Jedis jedis = redisClient.getResource();
String cacheContent = null;
try {
cacheContent = jedis.get("hello_world");
}finally {
redisClient.close();
}
//获取redis数据之后，立即释放连接，然后开始进行业务处理
if(cacheContent == null) {
//DB operation
}
//..
二、基于M-S模式下读写分离
通常情况下，Slave只是作为数据备份，不提供read操作，这种考虑是为了避免slave提供stale数据而导致一些问题。不过在很多场景下，即使slave数据有一定的延迟，我们仍然可以兼容或者正常处理，此时我们可以将slave提供read服务，并在M-S集群中将read操作分流，此时我们的Redis集群将可以支撑更高的QPS。
本文实例中，仅仅提供了“读写分离”的样板，尚未对所有的redis方法进行重写和封装，请开发者后续继续补充即可。此外，slave节点如果异常，我们应该支持failover，这一部分特性后续在扩展。
1、ReadWriteRedisClient.java
public class ReadWriteRedisClient implements InitializingBean {
//master:port,slave:port,slave:port...
//master first
private String hosts;
private JedisPool master;
private List slaves = new ArrayList<>();
private int maxTotal = 128;
//最大空闲连接数
private int maxIdle = 2;
//最小空闲连接数
private int minIdle = 1;
//如果连接池耗尽，最大阻塞的时间，默认为6秒
private long maxWait = 6000;//单位毫秒
private int database = 0;//选择数据库，默认为0
private int timeout = 3000;//connectionTimeout，soTimeout，默认为30秒
private boolean testOnBorrow = true;
private boolean testOnReturn = true;
private String password;
private Random random = new Random();
public void setMaxTotal(int maxTotal) {
this.maxTotal = maxTotal;
}
public void setMaxIdle(int maxIdle) {
this.maxIdle = maxIdle;
}
public void setMinIdle(int minIdle) {
this.minIdle = minIdle;
}
public void setMaxWait(long maxWait) {
this.maxWait = maxWait;
}
public void setDatabase(int database) {
this.database = database;
}
public void setTimeout(int timeout) {
this.timeout = timeout;
}
public void setTestOnBorrow(boolean testOnBorrow) {
this.testOnBorrow = testOnBorrow;
}
public void setTestOnReturn(boolean testOnReturn) {
this.testOnReturn = testOnReturn;
}
public void setPassword(String password) {
this.password = password;
}
public void setHosts(String hosts) {
this.hosts = hosts;
}
protected JedisPoolConfig buildConfig() {
JedisPoolConfig config = new JedisPoolConfig();
config.setMinIdle(minIdle);
config.setMaxIdle(maxIdle);
config.setMaxTotal(maxTotal);
config.setTestOnBorrow(testOnBorrow);
config.setTestOnReturn(testOnReturn);
config.setBlockWhenExhausted(true);
config.setMaxWaitMillis(maxWait);
config.setFairness(false);
return config;
}
@Override
public void afterPropertiesSet() throws Exception {
JedisPoolConfig config = buildConfig();
String[] hostAndPorts = hosts.split(",");
String masterHP = hostAndPorts[0];
String[] ms = masterHP.split(":");
master = new JedisPool(config,ms[0],Integer.valueOf(ms[1]),timeout, password, database,null);
if(hostAndPorts.length > 1) {
for(int i = 1; i < hostAndPorts.length; i++) {
String[] ss = hostAndPorts[i].split(":");
JedisPool slave = new JedisPool(config,ss[0],Integer.valueOf(ss[1]),timeout, password, database,null);
slaves.add(slave);
}
}
slaves.add(master);
}
public String get(String key) {
Jedis jedis = fetchResource(true);
try {
return jedis.get(key);
} finally {
jedis.close();
}
}
public List mget(String... keys) {
Jedis jedis = fetchResource(true);
try {
return jedis.mget(keys);
} finally {
jedis.close();
}
}
public String setex(String key,int seconds,String value) {
Jedis jedis = fetchResource(false);
try {
return jedis.setex(key,seconds,value);
} finally {
jedis.close();
}
}
public Long setnx(String key,String value) {
Jedis jedis = fetchResource(false);
try {
return jedis.setnx(key,value);
} finally {
jedis.close();
}
}
public String set(String key,String value) {
Jedis jedis = fetchResource(false);
try {
return jedis.set(key,value);
} finally {
jedis.close();
}
}
public Long del(String key) {
Jedis jedis = fetchResource(false);
try {
return jedis.del(key);
} finally {
jedis.close();
}
}
public Long expire(String key,int seconds) {
Jedis jedis = fetchResource(false);
try {
return jedis.expire(key,seconds);
} finally {
jedis.close();
}
}
public Boolean exists(String key) {
Jedis jedis = fetchResource(false);
try {
return jedis.exists(key);
} finally {
jedis.close();
}
}
public Long exists(String... keys) {
Jedis jedis = fetchResource(false);
try {
return jedis.exists(keys);
} finally {
jedis.close();
}
}
private Jedis fetchResource(boolean read) {
if(slaves.isEmpty() || !read) {
return master.getResource();
}
int size = slaves.size();
int i = random.nextInt(size);
return slaves.get(i).getResource();
}
public static void main(String[] args) throws Exception {
String prefix = "_test_";
ReadWriteRedisClient client = new ReadWriteRedisClient();
client.setHosts("127.0.0.1:6379,127.0.0.1:6379");
client.afterPropertiesSet();
client.set(prefix + "10001","test");
System.out.println(client.get(prefix + "10001"));
}
}
2、Spring.xml配置
3、客户端使用
@Autowired
private JedisPool redisClient;
public void test() {
Jedis jedis = redisClient.getResource();
//..
String cacheContent = null;
try {
cacheContent = readWriteRedisClient.get("hello_world");
} catch (Exception e) {
//如果redis网络异常， 你可以选择重新抛出，或者忽略
}
if(cacheContent == null) {
//redis中不存在，或者异常
}
}
三、基于Cluster模式的客户端
JedisCluster实例的简单封装，内部仍然基于连接池。需要注意，cluster模式下，mget等这种multi-keys操作将不再支持。其实我们无论如何封装，都无法非常合理的解决multi-keys问题，这里涉及到K-V在集群中的迁移、节点可用性、批量操作的异常处理，特别在异常处理时，如果某个key操作异常（可能对应的redis节点异常），那么其他已经操作成功的keys、或者后续尚未操作的keys该如何处理？这个答案是模糊不清的。此外，我们JAVA开发者通常会使用线程池 + Future机制来分解multi-keys操作，其实这会带来很大的性能隐患，不建议使用。
本人最终决定，保留redis Cluster的api方式，不做特殊封装，仅仅让其在spring环境中更易于使用即可。
1、ClusterClientFactoryBean.java
public class ClusterClientFactoryBean implements FactoryBean,InitializingBean {
private JedisCluster jedisCluster;
private int maxTotal = 128;
//最大空闲连接数
private int maxIdle = 6;
//最小空闲连接数
private int minIdle = 1;
//如果连接池耗尽，最大阻塞的时间，默认为6秒
private long maxWait = 6000;//单位毫秒
private int timeout = 3000;//connectionTimeout，soTimeout，默认为3秒
private boolean testOnBorrow = true;
private boolean testOnReturn = true;
private String addresses;//ip:port;ip:port
public void setMaxTotal(int maxTotal) {
this.maxTotal = maxTotal;
}
public void setMaxIdle(int maxIdle) {
this.maxIdle = maxIdle;
}
public void setMinIdle(int minIdle) {
this.minIdle = minIdle;
}
public void setMaxWait(long maxWait) {
this.maxWait = maxWait;
}
public void setTimeout(int timeout) {
this.timeout = timeout;
}
public void setTestOnBorrow(boolean testOnBorrow) {
this.testOnBorrow = testOnBorrow;
}
public void setTestOnReturn(boolean testOnReturn) {
this.testOnReturn = testOnReturn;
}
public void setAddresses(String addresses) {
this.addresses = addresses;
}
protected JedisPoolConfig buildConfig() {
JedisPoolConfig config = new JedisPoolConfig();
config.setMinIdle(minIdle);
config.setMaxIdle(maxIdle);
config.setMaxTotal(maxTotal);
config.setTestOnBorrow(testOnBorrow);
config.setTestOnReturn(testOnReturn);
config.setBlockWhenExhausted(true);
config.setMaxWaitMillis(maxWait);
config.setFairness(false);
return config;
}
private Set buildHostAndPorts() {
String[] hostPorts = addresses.split(",");
Set hostAndPorts = new HashSet<>();
for(String item : hostPorts) {
String[] hostPort = item.split(":");
HostAndPort hostAndPort = new HostAndPort(hostPort[0],Integer.valueOf(hostPort[1]));
hostAndPorts.add(hostAndPort);
}
return hostAndPorts;
}
@Override
public void afterPropertiesSet() throws Exception {
JedisPoolConfig config = buildConfig();
Set hostAndPorts = buildHostAndPorts();
jedisCluster = new JedisCluster(hostAndPorts,timeout,config);
}
@Override
public JedisCluster getObject() throws Exception {
return jedisCluster;
}
@Override
public Class getObjectType() {
return JedisCluster.class;
}
@Override
public boolean isSingleton() {
return true;
}
}
2、Spring.xml配置
3、客户端使用
@Autowired
private JedisCluster clusterRedisClient;
public void test() {
String cacheContent = null;
try {
cacheContent = clusterRedisClient.get("hello_world");
} catch (Exception e) {
//如果异常，你可以决定是否忽略
}
if(cacheContent == null) {
//如果cache中不存在，或者redis异常
}
}