JedisPool使用原理及源代码

摘要：，的使用连接池的配置信息说明一个可以有多少个实例最大最小获得一个实例的时候是否检查连接可用性一个实例给时，是否检查连接可用性状态监测用异步线程进行检查，一次最多的里的实例个数

1，JedisPool的使用

//WHEN_EXHAUSTED_FAIL = 0; 直接抛出异常throw new NoSuchElementException("Pool exhausted");
//WHEN_EXHAUSTED_BLOCK = 1;borrowObject()将会阻塞，直到有可用新的或者空闲的object为止，或者如果配置了maxWait，
//如果请求阻塞超时，将抛出NoSuchElementException.如果maxWait为负数，请求将会无限制的阻
//塞下去，默认配置。
//WHEN_EXHAUSTED_GROW = 2;borrowObject()将会继续创建新的对象，并返回，因此，pool维护的对像数将超出maxActive；
//

public String set(String key, String value) {
Jedis jedis = null;
boolean success = true;
try {
jedis = this.pool.getResource();
return jedis.set(key, value);
}catch (JedisException e) {
success = false;
if(jedis != null){
pool.returnBrokenResource(jedis);
}
throw e;
}finally{
if(success && jedis != null){
this.pool.returnResource(jedis);
}
}
}
获取Jedis

pool.getResource();
这个可以直接看Pool的getResource方法,

最终还是GenericObjectPool的borrowObject()方法借用对象

@SuppressWarnings("unchecked")
public T getResource() {
try {
return (T) internalPool.borrowObject();
} catch (Exception e) {
throw new JedisConnectionException(
"Could not get a resource from the pool", e);
}
}
用完归还,调用的是GenericObjectPool的returnObject（)方法

pool.returnResource(jedis)
//JedisPool.java
public void returnResource(final BinaryJedis resource) {
returnResourceObject(resource);
}
//Pool.java
public void returnResourceObject(final Object resource) {
try {
internalPool.returnObject(resource);
} catch (Exception e) {
throw new JedisException(
"Could not return the resource to the pool", e);
}
}
出错，调用的是GenericObjectPool的invalidateObject（)方法

最后在JedisFactory的destroyObject（）中调用jedis.quit()请求Server关闭连接

pool.returnBrokenResource(jedis)
//JedisPool.java
public void returnBrokenResource(final BinaryJedis resource) {
returnBrokenResourceObject(resource);
}
//Pool.java
protected void returnBrokenResourceObject(final Object resource) {
try {
//失效
internalPool.invalidateObject(resource);
} catch (Exception e) {
throw new JedisException(
"Could not return the resource to the pool", e);
}
}
//GenericObjectPool
public void invalidateObject(Object obj)
throws Exception
{
try
{
if (this._factory != null)
this._factory.destroyObject(obj);
}
finally {
synchronized (this) {
this._numActive -= 1;
allocate();
}
}
}
//JedisFactory
public void destroyObject(final Object obj) throws Exception {
if (obj instanceof Jedis) {
final Jedis jedis = (Jedis) obj;
if (jedis.isConnected()) {
try {
try {
jedis.quit();
} catch (Exception e) {
}
jedis.disconnect();
} catch (Exception e) {

        }
    }
}

}
JedisPool源代码

package redis.clients.jedis;

import org.apache.commons.pool.BasePoolableObjectFactory;
import org.apache.commons.pool.impl.GenericObjectPool.Config;

import redis.clients.util.Pool;

public class JedisPool extends Pool {

public JedisPool(final Config poolConfig, final String host) {
    this(poolConfig, host, Protocol.DEFAULT_PORT, Protocol.DEFAULT_TIMEOUT, null, Protocol.DEFAULT_DATABASE);
}

public JedisPool(String host, int port) {
    this(new Config(), host, port, Protocol.DEFAULT_TIMEOUT, null, Protocol.DEFAULT_DATABASE);
}

public JedisPool(final String host) {
    this(host, Protocol.DEFAULT_PORT);
}

public JedisPool(final Config poolConfig, final String host, int port,
        int timeout, final String password) {
    this(poolConfig, host, port, timeout, password, Protocol.DEFAULT_DATABASE);
}

public JedisPool(final Config poolConfig, final String host, final int port) {
    this(poolConfig, host, port, Protocol.DEFAULT_TIMEOUT, null, Protocol.DEFAULT_DATABASE);
}

public JedisPool(final Config poolConfig, final String host, final int port, final int timeout) {
    this(poolConfig, host, port, timeout, null, Protocol.DEFAULT_DATABASE);
}

public JedisPool(final Config poolConfig, final String host, int port, int timeout, final String password,
                 final int database) {
    super(poolConfig, new JedisFactory(host, port, timeout, password, database));
}


public void returnBrokenResource(final BinaryJedis resource) {
    returnBrokenResourceObject(resource);
}

public void returnResource(final BinaryJedis resource) {
    returnResourceObject(resource);
}

/**
 * PoolableObjectFactory custom impl.
 */
private static class JedisFactory extends BasePoolableObjectFactory {
    private final String host;
    private final int port;
    private final int timeout;
    private final String password;
    private final int database;

    public JedisFactory(final String host, final int port,
            final int timeout, final String password, final int database) {
        super();
        this.host = host;
        this.port = port;
        this.timeout = timeout;
        this.password = password;
        this.database = database;
    }

    public Object makeObject() throws Exception {
        final Jedis jedis = new Jedis(this.host, this.port, this.timeout);

        jedis.connect();
        if (null != this.password) {
            jedis.auth(this.password);
        }
        if( database != 0 ) {
            jedis.select(database);
        }

        return jedis;
    }

    public void destroyObject(final Object obj) throws Exception {
        if (obj instanceof Jedis) {
            final Jedis jedis = (Jedis) obj;
            if (jedis.isConnected()) {
                try {
                    try {
                        jedis.quit();
                    } catch (Exception e) {
                    }
                    jedis.disconnect();
                } catch (Exception e) {

                }
            }
        }
    }

    public boolean validateObject(final Object obj) {
        if (obj instanceof Jedis) {
            final Jedis jedis = (Jedis) obj;
            try {
                return jedis.isConnected();/* && jedis.ping().equals("PONG");*/
            } catch (final Exception e) {
                return false;
            }
        } else {
            return false;
        }
    }
}

}
其中JedisFactory继承自BasePoolableObjectFactory，只实现了3个方法

makeObject(),连接，new Socket()

destroyObject()--断开连接,

validateObject()--ping

Pool源代码

package redis.clients.util;

import org.apache.commons.pool.PoolableObjectFactory;
import org.apache.commons.pool.impl.GenericObjectPool;

import redis.clients.jedis.exceptions.JedisConnectionException;
import redis.clients.jedis.exceptions.JedisException;

public abstract class Pool {
private final GenericObjectPool internalPool;

public Pool(final GenericObjectPool.Config poolConfig,
        PoolableObjectFactory factory) {
    this.internalPool = new GenericObjectPool(factory, poolConfig);
}

@SuppressWarnings("unchecked")
public T getResource() {
    try {
        return (T) internalPool.borrowObject();
    } catch (Exception e) {
        throw new JedisConnectionException(
                "Could not get a resource from the pool", e);
    }
}

public void returnResourceObject(final Object resource) {
    try {
        internalPool.returnObject(resource);
    } catch (Exception e) {
        throw new JedisException(
                "Could not return the resource to the pool", e);
    }
}

public void returnBrokenResource(final T resource) {
    returnBrokenResourceObject(resource);
}

public void returnResource(final T resource) {
    returnResourceObject(resource);
}

protected void returnBrokenResourceObject(final Object resource) {
    try {
        //失效
        internalPool.invalidateObject(resource);
    } catch (Exception e) {
        throw new JedisException(
                "Could not return the resource to the pool", e);
    }
}

public void destroy() {
    try {
        internalPool.close();
    } catch (Exception e) {
        throw new JedisException("Could not destroy the pool", e);
    }
}

}
JedisPoolConfig源代码

public class JedisPoolConfig extends Config {
public JedisPoolConfig() {
// defaults to make your life with connection pool easier :)
setTestWhileIdle(true);
setMinEvictableIdleTimeMillis(60000);
setTimeBetweenEvictionRunsMillis(30000);
setNumTestsPerEvictionRun(-1);
}

public int getMaxIdle() {
    return maxIdle;
}

public void setMaxIdle(int maxIdle) {
    this.maxIdle = maxIdle;
}

public int getMinIdle() {
    return minIdle;
}

public void setMinIdle(int minIdle) {
    this.minIdle = minIdle;
}

public int getMaxActive() {
    return maxActive;
}

public void setMaxActive(int maxActive) {
    this.maxActive = maxActive;
}

public long getMaxWait() {
    return maxWait;
}

public void setMaxWait(long maxWait) {
    this.maxWait = maxWait;
}

public byte getWhenExhaustedAction() {
    return whenExhaustedAction;
}

public void setWhenExhaustedAction(byte whenExhaustedAction) {
    this.whenExhaustedAction = whenExhaustedAction;
}

public boolean isTestOnBorrow() {
    return testOnBorrow;
}

public void setTestOnBorrow(boolean testOnBorrow) {
    this.testOnBorrow = testOnBorrow;
}

public boolean isTestOnReturn() {
    return testOnReturn;
}

public void setTestOnReturn(boolean testOnReturn) {
    this.testOnReturn = testOnReturn;
}

public boolean isTestWhileIdle() {
    return testWhileIdle;
}

public void setTestWhileIdle(boolean testWhileIdle) {
    this.testWhileIdle = testWhileIdle;
}

public long getTimeBetweenEvictionRunsMillis() {
    return timeBetweenEvictionRunsMillis;
}

public void setTimeBetweenEvictionRunsMillis(
        long timeBetweenEvictionRunsMillis) {
    this.timeBetweenEvictionRunsMillis = timeBetweenEvictionRunsMillis;
}

public int getNumTestsPerEvictionRun() {
    return numTestsPerEvictionRun;
}

public void setNumTestsPerEvictionRun(int numTestsPerEvictionRun) {
    this.numTestsPerEvictionRun = numTestsPerEvictionRun;
}

public long getMinEvictableIdleTimeMillis() {
    return minEvictableIdleTimeMillis;
}

public void setMinEvictableIdleTimeMillis(long minEvictableIdleTimeMillis) {
    this.minEvictableIdleTimeMillis = minEvictableIdleTimeMillis;
}

public long getSoftMinEvictableIdleTimeMillis() {
    return softMinEvictableIdleTimeMillis;
}

public void setSoftMinEvictableIdleTimeMillis(
        long softMinEvictableIdleTimeMillis) {
    this.softMinEvictableIdleTimeMillis = softMinEvictableIdleTimeMillis;
}

}