JedisPool使用原理及源代碼

newtrek 發布于2019-08-14 11:39 / 2726人閱讀

摘要：，的使用連接池的配置信息說明一個可以有多少個實例最大最小獲得一個實例的時候是否檢查連接可用性一個實例給時，是否檢查連接可用性狀態監測用異步線程進行檢查，一次最多的里的實例個數

1，JedisPool的使用

//WHEN_EXHAUSTED_FAIL = 0; 直接拋出異常throw new NoSuchElementException("Pool exhausted");
//WHEN_EXHAUSTED_BLOCK = 1;borrowObject()將會阻塞，直到有可用新的或者空閑的object為止，或者如果配置了maxWait，
//如果請求阻塞超時，將拋出NoSuchElementException.如果maxWait為負數，請求將會無限制的阻
//塞下去，默認配置。
//WHEN_EXHAUSTED_GROW = 2;borrowObject()將會繼續創建新的對象，并返回，因此，pool維護的對像數將超出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);
}
}
}
獲取Jedis

pool.getResource();
這個可以直接看Pool的getResource方法,

最終還是GenericObjectPool的borrowObject()方法借用對象

@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);
}
}
用完歸還,調用的是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);
}
}
出錯，調用的是GenericObjectPool的invalidateObject（)方法

最后在JedisFactory的destroyObject（）中調用jedis.quit()請求Server關閉連接

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源代碼

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繼承自BasePoolableObjectFactory，只實現了3個方法

makeObject(),連接，new Socket()

destroyObject()--斷開連接,

validateObject()--ping

Pool源代碼

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源代碼

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;
}

}

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