jdbc链接oracle数据库查询

package com.zhuwei.util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;

import javax.management.Query;

public class DriverManger {
 private static String driverClass="oracle.jdbc.driver.OracleDriver";
 private static String urlString="jdbc:oracle:thin:@123.196.121.30:1521:orcl";
 private static String user="club";
 private static String password="club";
 private static Connection connection=null;
 static{
  if(connection==null)
   connection=getconnection();
 }
 public static Connection getconnection(){
  try {
   Class.forName(driverClass);
   Connection con=DriverManager.getConnection(urlString,user,password);
   return con;
  } catch (ClassNotFoundException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
   return null;
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
   return null;
  }
 }
 public static void query(String sql){
  try {
   if(connection==null){
    throw new Exception("没有连接");
   }
   if(sql.trim().equals("")){
    throw new Exception("sql为空");
   }
   PreparedStatement pStatement=connection.prepareStatement(sql);
   ResultSet rSet=pStatement.executeQuery();
   ResultSetMetaData rMetaData=rSet.getMetaData();
   int numColumns=rMetaData.getColumnCount();
   while(rSet.next()){
    for(int i=0;i<numColumns;i++){
     System.out.println(rMetaData.getColumnName(i+1)+" : "+rMetaData.getColumnType(i+1)+" : "+rMetaData.getColumnTypeName(i+1)+" : "+rMetaData.getColumnLabel(i+1)+" : "+rMetaData.getPrecision(i+1)+" : "+rSet.getObject(i+1));
    }
   }
  } catch (Exception e) {
   e.printStackTrace();
  }
  
 }
 public static void main(String[] args) {
  query("select * from club where id<929");
 }
}