iface) throws SQLException {return con.isWrapperFor(iface);}}
public class MyDataSource implements DataSource{//定义集合容器，用于保存多个数据库连接对象private static List pool = Collections.synchronizedList(new ArrayList());//静态代码块，生成10个数据库连接保存到集合中static {for (int i = 0; i < 10; i++) {Connection con = JDBCUtils.getConnection();pool.add(con);}}//返回连接池的大小public int getSize() {return pool.size();}//从池中返回一个数据库连接@Overridepublic Connection getConnection() {if(pool.size() > 0) {//从池中获取数据库连接Connection con = pool.remove(0);//通过自定义连接对象进行包装MyConnection2 mycon = new MyConnection2(con,pool);//返回包装后的连接对象return mycon;}else {throw new RuntimeException("连接数量已用尽");}}}
（3）适配器模式
通过之前连接类我们发现，发现装饰设计模式还是麻烦，有很多个需要实现的方法 。这个时候我们就可以使用适配器设计模式了 。提供一个适配器类，实现接口，将所有功能进行实现(除了close方法) 。自定义连接类只需要继承这个适配器类，重写需要改进的close()方法即可！
public abstract class MyAdapter implements Connection {// 定义数据库连接对象的变量private Connection con;// 通过构造方法赋值public MyAdapter(Connection con) {this.con = con;}// 所有的方法，均调用mysql的连接对象实现@Overridepublic Statement createStatement() throws SQLException {return con.createStatement();}@Overridepublic PreparedStatement prepareStatement(String sql) throws SQLException {return con.prepareStatement(sql);}@Overridepublic CallableStatement prepareCall(String sql) throws SQLException {return con.prepareCall(sql);}@Overridepublic String nativeSQL(String sql) throws SQLException {return con.nativeSQL(sql);}@Overridepublic void setAutoCommit(boolean autoCommit) throws SQLException {con.setAutoCommit(autoCommit);}@Overridepublic boolean getAutoCommit() throws SQLException {return con.getAutoCommit();}@Overridepublic void commit() throws SQLException {con.commit();}@Overridepublic void rollback() throws SQLException {con.rollback();}@Overridepublic boolean isClosed() throws SQLException {return con.isClosed();}@Overridepublic DatabaseMetaData getMetaData() throws SQLException {return con.getMetaData();}@Overridepublic void setReadOnly(boolean readOnly) throws SQLException {con.setReadOnly(readOnly);}@Overridepublic boolean isReadOnly() throws SQLException {return con.isReadOnly();}@Overridepublic void setCatalog(String catalog) throws SQLException {con.setCatalog(catalog);}@Overridepublic String getCatalog() throws SQLException {return con.getCatalog();}@Overridepublic void setTransactionIsolation(int level) throws SQLException {con.setTransactionIsolation(level);}@Overridepublic int getTransactionIsolation() throws SQLException {return con.getTransactionIsolation();}@Overridepublic SQLWarning getWarnings() throws SQLException {return con.getWarnings();}@Overridepublic void clearWarnings() throws SQLException {con.clearWarnings();}@Overridepublic Statement createStatement(int resultSetType, int resultSetConcurrency) throws SQLException {return con.createStatement(resultSetType,resultSetConcurrency);}@Overridepublic PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency) throws SQLException {return con.prepareStatement(sql,resultSetType,resultSetConcurrency);}@Overridepublic CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency) throws SQLException {return con.prepareCall(sql,resultSetType,resultSetConcurrency);}@Overridepublic Map> getTypeMap() throws SQLException {return con.getTypeMap();}@Overridepublic void setTypeMap(Map> map) throws SQLException {con.setTypeMap(map);}@Overridepublic void setHoldability(int holdability) throws SQLException {con.setHoldability(holdability);}@Overridepublic int getHoldability() throws SQLException {return con.getHoldability();}@Overridepublic Savepoint setSavepoint() throws SQLException {return con.setSavepoint();}@Overridepublic Savepoint setSavepoint(String name) throws SQLException {return con.setSavepoint(name);}@Overridepublic void rollback(Savepoint savepoint) throws SQLException {con.rollback(savepoint);}@Overridepublic void releaseSavepoint(Savepoint savepoint) throws SQLException {con.releaseSavepoint(savepoint);}@Overridepublic Statement createStatement(int resultSetType, int resultSetConcurrency, int resultSetHoldability) throws SQLException {return con.createStatement(resultSetType,resultSetConcurrency,resultSetHoldability);}@Overridepublic PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency, int resultSetHoldability) throws SQLException {return con.prepareStatement(sql,resultSetType,resultSetConcurrency,resultSetHoldability);}@Overridepublic CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency, int resultSetHoldability) throws SQLException {return con.prepareCall(sql,resultSetType,resultSetConcurrency,resultSetHoldability);}@Overridepublic PreparedStatement prepareStatement(String sql, int autoGeneratedKeys) throws SQLException {return con.prepareStatement(sql,autoGeneratedKeys);}@Overridepublic PreparedStatement prepareStatement(String sql, int[] columnIndexes) throws SQLException {return con.prepareStatement(sql,columnIndexes);}@Overridepublic PreparedStatement prepareStatement(String sql, String[] columnNames) throws SQLException {return con.prepareStatement(sql,columnNames);}@Overridepublic Clob createClob() throws SQLException {return con.createClob();}@Overridepublic Blob createBlob() throws SQLException {return con.createBlob();}@Overridepublic NClob createNClob() throws SQLException {return con.createNClob();}@Overridepublic SQLXML createSQLXML() throws SQLException {return con.createSQLXML();}@Overridepublic boolean isValid(int timeout) throws SQLException {return con.isValid(timeout);}@Overridepublic void setClientInfo(String name, String value) throws SQLClientInfoException {con.setClientInfo(name,value);}@Overridepublic void setClientInfo(Properties properties) throws SQLClientInfoException {con.setClientInfo(properties);}@Overridepublic String getClientInfo(String name) throws SQLException {return con.getClientInfo(name);}@Overridepublic Properties getClientInfo() throws SQLException {return con.getClientInfo();}@Overridepublic Array createArrayOf(String typeName, Object[] elements) throws SQLException {return con.createArrayOf(typeName,elements);}@Overridepublic Struct createStruct(String typeName, Object[] attributes) throws SQLException {return con.createStruct(typeName,attributes);}@Overridepublic void setSchema(String schema) throws SQLException {con.setSchema(schema);}@Overridepublic String getSchema() throws SQLException {return con.getSchema();}@Overridepublic void abort(Executor executor) throws SQLException {con.abort(executor);}@Overridepublic void setNetworkTimeout(Executor executor, int milliseconds) throws SQLException {con.setNetworkTimeout(executor,milliseconds);}@Overridepublic int getNetworkTimeout() throws SQLException {return con.getNetworkTimeout();}@Overridepublic T unwrap(Class iface) throws SQLException {return con.unwrap(iface);}@Overridepublic boolean isWrapperFor(Class