连接池增强close方法的原理

}

}
class MyDataSource implements DataSource{
List<Connection> list = new ArrayList<Connection>();
public MyDataSource() {//我的链接池一初始化就有5个链接
for (int i = 0; i < 5; i++) {
try {
Class.forName("com.mysql.jdbc.Driver");
Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root","root");
list.add(connection);
} catch (ClassNotFoundException | SQLException e) {
e.printStackTrace();
}

    }
}
/**
 * 获得增强后的链接
 */
@Override
public Connection getConnection() throws SQLException {
    Connection connection = list.remove(0);
    ConnectionWrapper connectionWrapper = new ConnectionWrapper(connection, list);
    return connectionWrapper;
}
@Override
public PrintWriter getLogWriter() throws SQLException {
    return null;
}

@Override
public void setLogWriter(PrintWriter out) throws SQLException {
}

@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;
}

}
/*

• 增强的类
• 缺点：被增强类中如果有多个方法，增强类中需要多次调用

• @author WangShuang
  */
  class ConnectionWrapper implements Connection{
  private Connection con;
  private List<Connection> list;

  public ConnectionWrapper(Connection con,List<Connection> list) {
      this.con=con;
      this.list=list;
  }
  @Override
  public void close() throws SQLException {
      list.add(con);
  }
  @Override
  public <T> T unwrap(Class<T> iface) throws SQLException {
      return con.unwrap(iface);
  }
  
  @Override
  public boolean isWrapperFor(Class<?> iface) throws SQLException {
      return con.isWrapperFor(iface);
  }
  
  @Override
  public Statement createStatement() throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public PreparedStatement prepareStatement(String sql) throws SQLException {
      return con.prepareStatement(sql);
  }
  
  @Override
  public CallableStatement prepareCall(String sql) throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public String nativeSQL(String sql) throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public void setAutoCommit(boolean autoCommit) throws SQLException {
      // TODO Auto-generated method stub
  
  }
  
  @Override
  public boolean getAutoCommit() throws SQLException {
      // TODO Auto-generated method stub
      return false;
  }
  
  @Override
  public void commit() throws SQLException {
      // TODO Auto-generated method stub
  
  }
  
  @Override
  public void rollback() throws SQLException {
      // TODO Auto-generated method stub
  
  }
  
  @Override
  public boolean isClosed() throws SQLException {
      // TODO Auto-generated method stub
      return false;
  }
  
  @Override
  public DatabaseMetaData getMetaData() throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public void setReadOnly(boolean readOnly) throws SQLException {
      // TODO Auto-generated method stub
  
  }
  
  @Override
  public boolean isReadOnly() throws SQLException {
      // TODO Auto-generated method stub
      return false;
  }
  
  @Override
  public void setCatalog(String catalog) throws SQLException {
      // TODO Auto-generated method stub
  
  }
  
  @Override
  public String getCatalog() throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public void setTransactionIsolation(int level) throws SQLException {
      // TODO Auto-generated method stub
  
  }
  
  @Override
  public int getTransactionIsolation() throws SQLException {
      // TODO Auto-generated method stub
      return 0;
  }
  
  @Override
  public SQLWarning getWarnings() throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public void clearWarnings() throws SQLException {
      // TODO Auto-generated method stub
  
  }
  
  @Override
  public Statement createStatement(int resultSetType, int resultSetConcurrency) throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency)
          throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency)
          throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public Map<String, Class<?>> getTypeMap() throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public void setTypeMap(Map<String, Class<?>> map) throws SQLException {
      // TODO Auto-generated method stub
  
  }
  
  @Override
  public void setHoldability(int holdability) throws SQLException {
      // TODO Auto-generated method stub
  
  }
  
  @Override
  public int getHoldability() throws SQLException {
      // TODO Auto-generated method stub
      return 0;
  }
  
  @Override
  public Savepoint setSavepoint() throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public Savepoint setSavepoint(String name) throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public void rollback(Savepoint savepoint) throws SQLException {
      // TODO Auto-generated method stub
  
  }
  
  @Override
  public void releaseSavepoint(Savepoint savepoint) throws SQLException {
      // TODO Auto-generated method stub
  
  }
  
  @Override
  public Statement createStatement(int resultSetType, int resultSetConcurrency, int resultSetHoldability)
          throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency,
          int resultSetHoldability) throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency,
          int resultSetHoldability) throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public PreparedStatement prepareStatement(String sql, int autoGeneratedKeys) throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public PreparedStatement prepareStatement(String sql, int[] columnIndexes) throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public PreparedStatement prepareStatement(String sql, String[] columnNames) throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public Clob createClob() throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public Blob createBlob() throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public NClob createNClob() throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public SQLXML createSQLXML() throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public boolean isValid(int timeout) throws SQLException {
      // TODO Auto-generated method stub
      return false;
  }
  
  @Override
  public void setClientInfo(String name, String value) throws SQLClientInfoException {
      // TODO Auto-generated method stub
  
  }
  
  @Override
  public void setClientInfo(Properties properties) throws SQLClientInfoException {
      // TODO Auto-generated method stub
  
  }
  
  @Override
  public String getClientInfo(String name) throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public Properties getClientInfo() throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public Array createArrayOf(String typeName, Object[] elements) throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public Struct createStruct(String typeName, Object[] attributes) throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public void setSchema(String schema) throws SQLException {
      // TODO Auto-generated method stub
  
  }
  
  @Override
  public String getSchema() throws SQLException {
      // TODO Auto-generated method stub
      return null;
  }
  
  @Override
  public void abort(Executor executor) throws SQLException {
      // TODO Auto-generated method stub
  
  }
  
  @Override
  public void setNetworkTimeout(Executor executor, int milliseconds) throws SQLException {
      // TODO Auto-generated method stub
  
  }
  
  @Override
  public int getNetworkTimeout() throws SQLException {
      // TODO Auto-generated method stub
      return 0;
  }

  }