在JDBC編程的時候千扔，獲取到一個數據庫連接資源是很寶貴的砸烦，倘若數據庫訪問量超大，而數據庫連接資源又沒能得到及時的釋放听盖，就會導致系統(tǒng)的崩潰甚至宕機胀溺。造成的損失將會是巨大的裂七。再看有了數據庫連接池的JDBC，就會較好的解決資源的創(chuàng)建與連接問題仓坞，其主要還是針對于連接資源使用層面的改進背零。下面我就談一談我對數據庫連接池的理解。

數據庫連接池理論基礎

對于創(chuàng)建一個數據庫連接池无埃，需要做好準備工作徙瓶。原理就是先實現(xiàn)DataSource接口，覆蓋里面的getConnection()方法嫉称，這個方法是我們最為關注的侦镇。既然是池，就不會是一個連接對象织阅，因此需要使用集合來保存這些個連接對象壳繁。
但是，最為關鍵的是荔棉，開發(fā)人員在使用完連接對象后通常會調用conn.close(),方法來釋放數據庫連接資源闹炉，這將會把數據庫連接返還給數據庫，而不是數據庫連接池润樱，因此渣触，數據庫連接池的存在就沒了意義了。所以我們要增強close方法壹若，來保證數據庫連接資源返還給數據庫連接池昵观。

創(chuàng)建數據庫連接池

public class JDCBCPool implements DataSource {

    /*
     * 既然是一個數據庫連接池，就必須有許多的連接舌稀，所以需要使用一個集合類保存這些連接 (non-Javadoc)
     * 
     * @see javax.sql.CommonDataSource#getLogWriter()
     */
    private static  LinkedList<Connection> list = new LinkedList<Connection>();

    // 創(chuàng)建一個配置文件，用于讀取相應配置文件中保存的數據信息
    private static Properties config = new Properties();

    /*
     * 在這里向數據庫申請一批數據庫連接 為了只加載一次驅動程序灼擂，因此在靜態(tài)代碼塊中進行聲明壁查，這樣驅動就只會加載一次
     */
    static {

        try {
            config.load(JDBCUtils.class.getClassLoader().getResourceAsStream("db.properties"));
            // Class.forName("com.mysql.jdbc.Driver");
            Class.forName(config.getProperty("DRIVER"));
            try {
                //申請十個數據庫連接對象，也就是數據庫連接池的容量是10
                for(int i=0 ;i<10;i++){
                    Connection conn =  DriverManager.getConnection(config.getProperty("URL"),
                            config.getProperty("USER"),config.getProperty("PASSWORD"));
                    list.add(conn);
                }
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        } catch (ClassNotFoundException | IOException e) {
            // TODO Auto-generated catch block
            throw new ExceptionInInitializerError();
        }
    }

    
    @Override
    public Connection getConnection() throws SQLException {
        
        if(list.size()<=0){
            throw new RuntimeException("數據庫忙剔应，請待會再試試吧睡腿！");
        }
        //需要注意的是，不能使用get方式（這個方法知識返回一個引用而已）,
        //應該在獲取的同時峻贮，刪除掉這個鏈接席怪，之后再還回來.現(xiàn)在注意是返還給數據庫連接池！Ｏ丝亍挂捻！
        Connection conn = list.removeFirst();
        MyConnection myconn = new MyConnection(conn);

        //從這里開始返回的就是一個數據庫連接池對象的conn
        return myconn;
    }

    
    
/////////////////////////////////////////////////////////////////////////datasource接口的實現(xiàn)方法開始    
    
    @Override
    public PrintWriter getLogWriter() throws SQLException {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public void setLogWriter(PrintWriter out) throws SQLException {
        // TODO Auto-generated method stub

    }

    @Override
    public void setLoginTimeout(int seconds) throws SQLException {
        // TODO Auto-generated method stub

    }

    @Override
    public int getLoginTimeout() throws SQLException {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public Logger getParentLogger() throws SQLFeatureNotSupportedException {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public <T> T unwrap(Class<T> iface) throws SQLException {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public boolean isWrapperFor(Class<?> iface) throws SQLException {
        // TODO Auto-generated method stub
        return false;
    }

    
    @Override
    public Connection getConnection(String username, String password) throws SQLException {
        // TODO Auto-generated method stub
        return null;
    }
}

不難看出，數據庫連接池相對于普通的數據庫連接的創(chuàng)建船万，并沒有什么特別難寫的部分刻撒。

增強close方法骨田，保證數據庫連接資源用完后返還給連接池

要想增強close方法的功能，一般來說我們有如下幾種方式声怔。

• 創(chuàng)建子類态贤，覆蓋close方法，但是創(chuàng)建子類的時候要實現(xiàn)的部分可能會特別多醋火，因此并不常用
• 使用包裝設計模式
• 使用動態(tài)代理方式

今天我就來實現(xiàn)一下怎么使用包裝設計模式來實現(xiàn)close方法的增強悠汽。

包裝設計模式實現(xiàn)close方法的增強

要實現(xiàn)包裝設計模式，思路很簡單芥驳。

• 創(chuàng)建一個類柿冲，實現(xiàn)與被增強對象相同的接口
• 將被增強對象作為一個成員變量加到這個類中
• 定義一個構造方法，并把被增強對象作為參數傳進來
• 覆蓋要增強的方法晚树，這里是close方法
• 對于不想進行增強的方法姻采，借助于被增強對象實現(xiàn)即可。

下面是基于包裝設計模式實現(xiàn)的增強的MyConnection類：

class MyConnection implements Connection {

        private Connection conn ;
        
        public MyConnection(Connection conn ){
            this.conn = conn;
        }
        
        /**
         * 自定義的包裝設計模式類爵憎，增強close方法慨亲，
         * 將數據庫鏈接資源返還給數據庫連接池，而不是數據庫
         */
        public void close(){
            list.add(conn);
        }

        @Override
        public <T> T unwrap(Class<T> iface) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.unwrap(iface);
        }

        @Override
        public boolean isWrapperFor(Class<?> iface) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.isWrapperFor(iface);
        }

        @Override
        public Statement createStatement() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createStatement();
        }

        @Override
        public PreparedStatement prepareStatement(String sql) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareStatement(sql);
        }

        @Override
        public CallableStatement prepareCall(String sql) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareCall(sql);
        }

        @Override
        public String nativeSQL(String sql) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.nativeSQL(sql);
        }

        @Override
        public void setAutoCommit(boolean autoCommit) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.setAutoCommit(autoCommit);
        }

        @Override
        public boolean getAutoCommit() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getAutoCommit();
        }

        @Override
        public void commit() throws SQLException {
            // TODO Auto-generated method stub
            this.conn.commit();
        }

        @Override
        public void rollback() throws SQLException {
            // TODO Auto-generated method stub
            this.conn.rollback();
        }

        @Override
        public boolean isClosed() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.isClosed();
        }

        @Override
        public DatabaseMetaData getMetaData() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getMetaData();
        }

        @Override
        public void setReadOnly(boolean readOnly) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.setReadOnly(readOnly);
        }

        @Override
        public boolean isReadOnly() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.isReadOnly();
        }

        @Override
        public void setCatalog(String catalog) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.setCatalog(catalog);
        }

        @Override
        public String getCatalog() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getCatalog();
        }

        @Override
        public void setTransactionIsolation(int level) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.setTransactionIsolation(level);
        }

        @Override
        public int getTransactionIsolation() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getTransactionIsolation();
        }

        @Override
        public SQLWarning getWarnings() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getWarnings();
        }

        @Override
        public void clearWarnings() throws SQLException {
            // TODO Auto-generated method stub
            this.conn.clearWarnings();
        }

        @Override
        public Statement createStatement(int resultSetType, int resultSetConcurrency) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createStatement(resultSetType, resultSetConcurrency);
        }

        @Override
        public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency)
                throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareStatement(sql, resultSetType, resultSetConcurrency);
        }

        @Override
        public CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareCall(sql, resultSetType, resultSetConcurrency);
        }

        @Override
        public Map<String, Class<?>> getTypeMap() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getTypeMap();
        }

        @Override
        public void setTypeMap(Map<String, Class<?>> map) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.setTypeMap(map);
        }

        @Override
        public void setHoldability(int holdability) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.setHoldability(holdability);
        }

        @Override
        public int getHoldability() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getHoldability();
        }

        @Override
        public Savepoint setSavepoint() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.setSavepoint();
        }

        @Override
        public Savepoint setSavepoint(String name) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.setSavepoint(name);
        }

        @Override
        public void rollback(Savepoint savepoint) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.rollback(savepoint);
        }

        @Override
        public void releaseSavepoint(Savepoint savepoint) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.releaseSavepoint(savepoint);
        }

        @Override
        public Statement createStatement(int resultSetType, int resultSetConcurrency, int resultSetHoldability)
                throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createStatement(resultSetType, resultSetConcurrency, resultSetHoldability);
        }

        @Override
        public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency,
                int resultSetHoldability) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareStatement(sql, resultSetType, resultSetConcurrency, resultSetHoldability);
        }

        @Override
        public CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency,
                int resultSetHoldability) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareCall(sql, resultSetType, resultSetConcurrency, resultSetHoldability);
        }

        @Override
        public PreparedStatement prepareStatement(String sql, int autoGeneratedKeys) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareStatement(sql, autoGeneratedKeys);
        }

        @Override
        public PreparedStatement prepareStatement(String sql, int[] columnIndexes) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareStatement(sql, columnIndexes);
        }

        @Override
        public PreparedStatement prepareStatement(String sql, String[] columnNames) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareStatement(sql, columnNames);
        }

        @Override
        public Clob createClob() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createClob();
        }

        @Override
        public Blob createBlob() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createBlob();
        }

        @Override
        public NClob createNClob() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createNClob();
        }

        @Override
        public SQLXML createSQLXML() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createSQLXML();
        }

        @Override
        public boolean isValid(int timeout) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.isValid(timeout);
        }

        @Override
        public void setClientInfo(String name, String value) throws SQLClientInfoException {
            // TODO Auto-generated method stub
            this.conn.setClientInfo(name, value);
        }

        @Override
        public void setClientInfo(Properties properties) throws SQLClientInfoException {
            // TODO Auto-generated method stub
            this.conn.setClientInfo(properties);
        }

        @Override
        public String getClientInfo(String name) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getClientInfo(name);
        }

        @Override
        public Properties getClientInfo() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getClientInfo();
        }

        @Override
        public Array createArrayOf(String typeName, Object[] elements) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createArrayOf(typeName, elements);
        }

        @Override
        public Struct createStruct(String typeName, Object[] attributes) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createStruct(typeName, attributes);
        }

        @Override
        public void setSchema(String schema) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.setSchema(schema);
        }

        @Override
        public String getSchema() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getSchema();
        }

        @Override
        public void abort(Executor executor) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.abort(executor);
        }

        @Override
        public void setNetworkTimeout(Executor executor, int milliseconds) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.setNetworkTimeout(executor, milliseconds);
        }

        @Override
        public int getNetworkTimeout() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getNetworkTimeout();
        }
        
        
        
    }

一個簡單的數據庫連接池的實現(xiàn)案例

說是一個案例，其實也可以作為一個工具類作為今后程序開發(fā)的使用，這將會大大的提升數據庫連接資源的使用屹徘。需要注意的是掌逛，里面的驅動程序是基于我自己的數據庫來書寫的，進行使用時記得修改一下配置文件db.properties.文件中的內容即可装盯。
db.properties中內容如下：

#when use this db.properties ,need to change the database name
DRIVER = com.mysql.jdbc.Driver
URL = jdbc:mysql://localhost:3306/test
USER = root
PASSWORD = mysql

下面就是JDBCPool工具類的實現(xiàn)：

package utils;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Array;
import java.sql.Blob;
import java.sql.CallableStatement;
import java.sql.Clob;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.NClob;
import java.sql.PreparedStatement;
import java.sql.SQLClientInfoException;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.sql.SQLWarning;
import java.sql.SQLXML;
import java.sql.Savepoint;
import java.sql.Statement;
import java.sql.Struct;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.Executor;
import java.util.logging.Logger;

import javax.sql.DataSource;

/**
 * 數據庫連接池工具類
 * 
 * @author Summer
 *
 */
public class JDCBCPool implements DataSource {

    /*
     * 既然是一個數據庫連接池，就必須有許多的連接，所以需要使用一個集合類保存這些連接 (non-Javadoc)
     * 
     * @see javax.sql.CommonDataSource#getLogWriter()
     */
    private static  LinkedList<Connection> list = new LinkedList<Connection>();

    // 創(chuàng)建一個配置文件碍舍，用于讀取相應配置文件中保存的數據信息
    private static Properties config = new Properties();

    /*
     * 在這里向數據庫申請一批數據庫連接 為了只加載一次驅動程序，因此在靜態(tài)代碼塊中進行聲明邑雅，這樣驅動就只會加載一次
     */
    static {

        try {
            config.load(JDBCUtils.class.getClassLoader().getResourceAsStream("db.properties"));
            // Class.forName("com.mysql.jdbc.Driver");
            Class.forName(config.getProperty("DRIVER"));
            try {
                //申請十個數據庫連接對象片橡，也就是數據庫連接池的容量是10
                for(int i=0 ;i<10;i++){
                    Connection conn =  DriverManager.getConnection(config.getProperty("URL"),
                            config.getProperty("USER"),config.getProperty("PASSWORD"));
                    list.add(conn);
                }
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        } catch (ClassNotFoundException | IOException e) {
            // TODO Auto-generated catch block
            throw new ExceptionInInitializerError();
        }
    }

    
    @Override
    public Connection getConnection() throws SQLException {
        
        if(list.size()<=0){
            throw new RuntimeException("數據庫忙，請待會再試試吧淮野！");
        }
        //需要注意的是捧书，不能使用get方式（這個方法知識返回一個引用而已）,
        //應該在獲取的同時，刪除掉這個鏈接骤星，之后再還回來.現(xiàn)在注意是返還給數據庫連接池＞伞！洞难！
        Connection conn = list.removeFirst();
        MyConnection myconn = new MyConnection(conn);

        //從這里開始返回的就是一個數據庫連接池對象的conn
        return myconn;
    }

    
    
/////////////////////////////////////////////////////////////////////////datasource接口的實現(xiàn)方法開始    
    
    @Override
    public PrintWriter getLogWriter() throws SQLException {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public void setLogWriter(PrintWriter out) throws SQLException {
        // TODO Auto-generated method stub

    }

    @Override
    public void setLoginTimeout(int seconds) throws SQLException {
        // TODO Auto-generated method stub

    }

    @Override
    public int getLoginTimeout() throws SQLException {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public Logger getParentLogger() throws SQLFeatureNotSupportedException {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public <T> T unwrap(Class<T> iface) throws SQLException {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public boolean isWrapperFor(Class<?> iface) throws SQLException {
        // TODO Auto-generated method stub
        return false;
    }

    
    @Override
    public Connection getConnection(String username, String password) throws SQLException {
        // TODO Auto-generated method stub
        return null;
    }
/////////////////////////////////////////////////////////////////////////datasource接口的實現(xiàn)方法結束
    
    /**
     * 包裝設計模式實現(xiàn)流程：
     * 1.創(chuàng)建一個類舆吮，實現(xiàn)與被增強對象相同的接口
     * 2.將被增強對象當做自定義類的一個成員變量
     * 3.定義一個構造方法，將被增強對象傳遞進去
     * 4.增強想要增強的方法，進行覆蓋即可
     * 5.對于不像被增強的方法歪泳，調用被增強對象的方法進行處理即可
     * @author Summer
     *
     */
    
///////////////////////////////////////////////////////////////////////使用包裝設計模式萝勤，增強close方法的自定義類開始
    class MyConnection implements Connection {

        private Connection conn ;
        
        public MyConnection(Connection conn ){
            this.conn = conn;
        }
        
        /**
         * 自定義的包裝設計模式類，增強close方法呐伞，
         * 將數據庫鏈接資源返還給數據庫連接池敌卓，而不是數據庫
         */
        public void close(){
            list.add(conn);
        }

        @Override
        public <T> T unwrap(Class<T> iface) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.unwrap(iface);
        }

        @Override
        public boolean isWrapperFor(Class<?> iface) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.isWrapperFor(iface);
        }

        @Override
        public Statement createStatement() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createStatement();
        }

        @Override
        public PreparedStatement prepareStatement(String sql) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareStatement(sql);
        }

        @Override
        public CallableStatement prepareCall(String sql) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareCall(sql);
        }

        @Override
        public String nativeSQL(String sql) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.nativeSQL(sql);
        }

        @Override
        public void setAutoCommit(boolean autoCommit) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.setAutoCommit(autoCommit);
        }

        @Override
        public boolean getAutoCommit() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getAutoCommit();
        }

        @Override
        public void commit() throws SQLException {
            // TODO Auto-generated method stub
            this.conn.commit();
        }

        @Override
        public void rollback() throws SQLException {
            // TODO Auto-generated method stub
            this.conn.rollback();
        }

        @Override
        public boolean isClosed() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.isClosed();
        }

        @Override
        public DatabaseMetaData getMetaData() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getMetaData();
        }

        @Override
        public void setReadOnly(boolean readOnly) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.setReadOnly(readOnly);
        }

        @Override
        public boolean isReadOnly() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.isReadOnly();
        }

        @Override
        public void setCatalog(String catalog) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.setCatalog(catalog);
        }

        @Override
        public String getCatalog() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getCatalog();
        }

        @Override
        public void setTransactionIsolation(int level) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.setTransactionIsolation(level);
        }

        @Override
        public int getTransactionIsolation() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getTransactionIsolation();
        }

        @Override
        public SQLWarning getWarnings() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getWarnings();
        }

        @Override
        public void clearWarnings() throws SQLException {
            // TODO Auto-generated method stub
            this.conn.clearWarnings();
        }

        @Override
        public Statement createStatement(int resultSetType, int resultSetConcurrency) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createStatement(resultSetType, resultSetConcurrency);
        }

        @Override
        public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency)
                throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareStatement(sql, resultSetType, resultSetConcurrency);
        }

        @Override
        public CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareCall(sql, resultSetType, resultSetConcurrency);
        }

        @Override
        public Map<String, Class<?>> getTypeMap() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getTypeMap();
        }

        @Override
        public void setTypeMap(Map<String, Class<?>> map) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.setTypeMap(map);
        }

        @Override
        public void setHoldability(int holdability) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.setHoldability(holdability);
        }

        @Override
        public int getHoldability() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getHoldability();
        }

        @Override
        public Savepoint setSavepoint() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.setSavepoint();
        }

        @Override
        public Savepoint setSavepoint(String name) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.setSavepoint(name);
        }

        @Override
        public void rollback(Savepoint savepoint) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.rollback(savepoint);
        }

        @Override
        public void releaseSavepoint(Savepoint savepoint) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.releaseSavepoint(savepoint);
        }

        @Override
        public Statement createStatement(int resultSetType, int resultSetConcurrency, int resultSetHoldability)
                throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createStatement(resultSetType, resultSetConcurrency, resultSetHoldability);
        }

        @Override
        public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency,
                int resultSetHoldability) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareStatement(sql, resultSetType, resultSetConcurrency, resultSetHoldability);
        }

        @Override
        public CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency,
                int resultSetHoldability) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareCall(sql, resultSetType, resultSetConcurrency, resultSetHoldability);
        }

        @Override
        public PreparedStatement prepareStatement(String sql, int autoGeneratedKeys) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareStatement(sql, autoGeneratedKeys);
        }

        @Override
        public PreparedStatement prepareStatement(String sql, int[] columnIndexes) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareStatement(sql, columnIndexes);
        }

        @Override
        public PreparedStatement prepareStatement(String sql, String[] columnNames) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.prepareStatement(sql, columnNames);
        }

        @Override
        public Clob createClob() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createClob();
        }

        @Override
        public Blob createBlob() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createBlob();
        }

        @Override
        public NClob createNClob() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createNClob();
        }

        @Override
        public SQLXML createSQLXML() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createSQLXML();
        }

        @Override
        public boolean isValid(int timeout) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.isValid(timeout);
        }

        @Override
        public void setClientInfo(String name, String value) throws SQLClientInfoException {
            // TODO Auto-generated method stub
            this.conn.setClientInfo(name, value);
        }

        @Override
        public void setClientInfo(Properties properties) throws SQLClientInfoException {
            // TODO Auto-generated method stub
            this.conn.setClientInfo(properties);
        }

        @Override
        public String getClientInfo(String name) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getClientInfo(name);
        }

        @Override
        public Properties getClientInfo() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getClientInfo();
        }

        @Override
        public Array createArrayOf(String typeName, Object[] elements) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createArrayOf(typeName, elements);
        }

        @Override
        public Struct createStruct(String typeName, Object[] attributes) throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.createStruct(typeName, attributes);
        }

        @Override
        public void setSchema(String schema) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.setSchema(schema);
        }

        @Override
        public String getSchema() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getSchema();
        }

        @Override
        public void abort(Executor executor) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.abort(executor);
        }

        @Override
        public void setNetworkTimeout(Executor executor, int milliseconds) throws SQLException {
            // TODO Auto-generated method stub
            this.conn.setNetworkTimeout(executor, milliseconds);
        }

        @Override
        public int getNetworkTimeout() throws SQLException {
            // TODO Auto-generated method stub
            return this.conn.getNetworkTimeout();
        }
        
        
        
    }
/////////////////////////////////////////////////////////////////////////////包裝設計模式結束
}

總結

• 在實際的開發(fā)過程中，數據庫連接池使用的很廣泛伶氢，我們應該加以掌握趟径。
• 數據庫連接對象應從數據庫連接池中獲取，使用完之后再返還給數據庫連接池
• 使用包裝設計模式進行方法的增強是較為合理的癣防，但是更為常用的是開源的數據庫連接池蜗巧，即動態(tài)代理方式。如DBCP等等