?1.定義自己的MyConnection

public class MyConnection {private static Logger logger = LoggerFactory.getLogger(MyConnection.class);private String name;private boolean connected;public MyConnection(String name) {this.name = name;}public void connect() {this.connected = true;logger.info(name + ": " + true);}public void close() {this.connected = false;logger.info(name + ": " + false);}public boolean isConnected() {return this.connected;}public String getName() {return this.name;}public void print() {logger.info(this.name);} }

2.定義工廠

public class MyConnectionFactory2 implements PooledObjectFactory<MyConnection> {private static Logger logger = LoggerFactory.getLogger(MyConnectionFactory.class);private static AtomicInteger count = new AtomicInteger(0);public PooledObject<MyConnection> makeObject() throws Exception {return new DefaultPooledObject<>(_makeObject());}@Override public void destroyObject(PooledObject<MyConnection> p) throws Exception {destroyObject(p.getObject());}@Override public boolean validateObject(PooledObject<MyConnection> p) {return validateObject(p.getObject());}@Override public void activateObject(PooledObject<MyConnection> p) throws Exception {activateObject(p.getObject());}@Override public void passivateObject(PooledObject<MyConnection> p) throws Exception {passivateObject(p.getObject());}private MyConnection _makeObject() throws Exception {MyConnection myConn = new MyConnection(generateName());logger.info(myConn.getName());myConn.connect();return myConn;}private void activateObject(MyConnection myConn) throws Exception {logger.info(myConn.getName());}private void passivateObject(MyConnection myConn) throws Exception {logger.info(myConn.getName());}private boolean validateObject(MyConnection myConn) {logger.info(myConn.getName());return myConn.isConnected();}private void destroyObject(MyConnection myConn) throws Exception {logger.info(myConn.getName());myConn.close();}private synchronized String generateName() {return "conn_" + (count.incrementAndGet());} }

池化對象工程，這里的池化對象是MyConnection，這個工廠就是負責產生MyConnection對象的，產生的對象會放到池子中。

3.初始化對象池

public static GenericObjectPool<MyConnection> initPool(int max, int min) {PooledObjectFactory<MyConnection> factory = new MyConnectionFactory2();GenericObjectPoolConfig config = new GenericObjectPoolConfig();config.setLifo(false);config.setMaxTotal(max);config.setMaxIdle(max);config.setMinIdle(min);config.setMaxWaitMillis(5 * 1000);// 取不到等待的超時間config.setTimeBetweenEvictionRunsMillis(5 * 1000);// 構造方法，會建立idle object，建立了兩個return new GenericObjectPool<>(factory, config);}

4.對象池中對象數量控制

初始化對象池，后臺Task {@link BaseGenericObjectPool.Evictor#run} 會調用{@link BaseGenericObjectPool#ensureMinIdle} 保證idleObjects
保證{@link GenericObjectPool#idleObjects} 對象的size和{@link GenericObjectPool#getMinIdle}一致。
但是如果 {@link GenericObjectPool#createCount} == {@link GenericObjectPool#maxTotal}
{@link GenericObjectPool#create} 方法就無法繼續創建對象了
{@link GenericObjectPool#borrowObject} 如果到了過期時間依然沒有獲取到
就會拋出異常 {@link java.util.NoSuchElementException} 異常
?

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