Analysis of MySql public method instance based on JDBC access

package com;
import .*;
import .*;
import ;
/**
  * @Description Database connection management
  * @author cuisuqiang
  */
public class ConnectionManager {
	/**
	  * @Description Execute a SQL
	  */
	@SuppressWarnings("unchecked")
	public static List<Object[]> excuteQuery(String sql) {
		Connection conn = null;
		PreparedStatement psta = null;
		ResultSet resultSet = null;
		List<Object[]> relist = new ArrayList<Object[]>(); // Total data		Object[] objects = null; // Each row of data		try {
			conn = (); // Get the link			if(null != conn){
				psta = (sql);
				resultSet = (); // Execute the query and return the result collection				int count = ().getColumnCount(); // How many columns of data are there in total				// Circular row				while (()) {
					objects = new Object[count];
					// The dataset index starts at 1, while the array is stored at 0					for (int i = 1; i <= count; i++) {
						objects[i - 1] = (i);
					}
					(objects);
				}
			}
		} catch (Exception e) {
			();
			relist = null;
		} finally {
			try {
				if(null != resultSet)
					();
				if(null != psta)
					();
				if(null != conn)
					();
			} catch (Exception e2) {
				
			}
		}
		return relist;
	}
	private static  ds = null;
	static {
		ds = new BasicDataSource(); // Create a data source object		int initialSize = 1; // Initial value when the connection pool starts		int maxActive = 10; // Maximum value of connection pool		int maxIdle = 1;   // Maximum idle value		int minIdle = 1;   // Minimum idle value		("");
		("jdbc:mysql://192.168.154.128:3306/t2?useUnicode=true&characterEncoding=gbk");
		("root");
		("123456");
		(initialSize);
		(maxActive);
		(maxIdle);
		(minIdle);
	}
	/**
	  * Get database connection from the data source
	  */
	public static Connection getConn() {
		try {
			return ();
		} catch (SQLException e) {
			();
		}
		return null;
	}
}

package com; 
import ; 
public class T { 
  @SuppressWarnings("unchecked") 
  public static void main(String[] args) { 
    try { 
      List<Object[]> list = ("select * from t"); 
      for (int i = 0; i < (); i++) { 
        Object[] os = (i); 
        for(Object o : os){ 
          if (o instanceof String) { 
            String s = (String) o; 
            String newStr = new String(("ISO-8859-1"),"GBK"); 
            ("String:" + newStr + "\t\t"); 
          }else if(o instanceof Long){ 
            Long s = (Long) o; 
            ("Floating point value:" + s + "\t\t"); 
          }else if(o instanceof Integer){ 
            Integer s = (Integer) o; 
            ("Surgery value:" + s + "\t\t"); 
          }else{ 
            ("Unknown type:" + o + "\t\t"); 
          } 
        } 
        (); 
      } 
    } catch (Exception e) { 
      (); 
    }     
  } 
}