基于JDBC访问MySql公共方法实例解析

package com;
import java.sql.*;
import java.util.*;
import org.apache.commons.dbcp.BasicDataSource;
/**
 * @说明 数据库连接管理
 * @author cuisuqiang
 */
public class ConnectionManager {
	/**
	 * @说明 执行一条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[]>(); // 总数据
		Object[] objects = null; // 每行数据
		try {
			conn = ConnectionManager.getConn(); // 得到链接
			if(null != conn){
				psta = conn.prepareStatement(sql);
				resultSet = psta.executeQuery(); // 执行查询，返回结果接集合
				int count = resultSet.getMetaData().getColumnCount(); // 一共有多少列数据
				// 循环行
				while (resultSet.next()) {
					objects = new Object[count];
					// 数据集索引从 1 开始，而数组存放时是从 0 开始
					for (int i = 1; i <= count; i++) {
						objects[i - 1] = resultSet.getObject(i);
					}
					relist.add(objects);
				}
			}
		} catch (Exception e) {
			e.printStackTrace();
			relist = null;
		} finally {
			try {
				if(null != resultSet)
					resultSet.close();
				if(null != psta)
					psta.close();
				if(null != conn)
					conn.close();
			} catch (Exception e2) {
				
			}
		}
		return relist;
	}
	private static org.apache.commons.dbcp.BasicDataSource ds = null;
	static {
		ds = new BasicDataSource(); // 组建数据源对象
		int initialSize = 1; // 连接池启动时的初始值
		int maxActive = 10; // 连接池的最大值
		int maxIdle = 1;   // 最大空闲值
		int minIdle = 1;   // 最小空闲值
		ds.setDriverClassName("com.mysql.jdbc.Driver");
		ds.setUrl("jdbc:mysql://192.168.154.128:3306/t2?useUnicode=true&characterEncoding=gbk");
		ds.setUsername("root");
		ds.setPassword("123456");
		ds.setInitialSize(initialSize);
		ds.setMaxActive(maxActive);
		ds.setMaxIdle(maxIdle);
		ds.setMinIdle(minIdle);
	}
	/**
	 * 从数据源中取得数据库连接
	 */
	public static Connection getConn() {
		try {
			return ds.getConnection();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return null;
	}
}

package com; 
import java.util.List; 
public class T { 
  @SuppressWarnings("unchecked") 
  public static void main(String[] args) { 
    try { 
      List<Object[]> list = ConnectionManager.excuteQuery("select * from t"); 
      for (int i = 0; i < list.size(); i++) { 
        Object[] os = list.get(i); 
        for(Object o : os){ 
          if (o instanceof String) { 
            String s = (String) o; 
            String newStr = new String(s.getBytes("ISO-8859-1"),"GBK"); 
            System.out.print("字符串：" + newStr + "\t\t"); 
          }else if(o instanceof Long){ 
            Long s = (Long) o; 
            System.out.print("浮点值：" + s + "\t\t"); 
          }else if(o instanceof Integer){ 
            Integer s = (Integer) o; 
            System.out.print("整形值：" + s + "\t\t"); 
          }else{ 
            System.out.print("未知型：" + o + "\t\t"); 
          } 
        } 
        System.out.println(); 
      } 
    } catch (Exception e) { 
      e.printStackTrace(); 
    }     
  } 
}