jdbc：连接oracle

版权声明：java洪君 https://blog.csdn.net/qq_43532342/article/details/85066598

jdbc是经典的数据库链接方式

 导入jar包，即链接包即可。在框架中，框架可以轻易做到连接数据库，拿取数据。

oracle版：

package com.hc.dao;

import java.sql.Connection;

import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class BaseDao {
//	OracleDriver
	private final static String fname="oracle.jdbc.driver.OracleDriver";
	private final static String url="jdbc:oracle:thin:@localhost:1521:orcl";
	static {
		try {
			Class.forName(fname);
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}
		
	}
	
	public static Connection getCon(){
		Connection con=null;
		try {
			con=DriverManager.getConnection(url,"scott","tiger");
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		return con;
		
	}
	
	public static void myClose(Connection con,Statement pre){
		
		try {
			if (pre!=null) {
				pre.close();
			}
			if (con!=null&&!con.isClosed()) {
				con.close();
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

		}
	
	public static void myClose(Connection con,Statement pre,ResultSet res){
	
	try {
		if (res!=null) {
			res.close();
		}
		if (pre!=null) {
			pre.close();
		}
		if (con!=null&&!con.isClosed()) {
			con.close();
		}
	} catch (SQLException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}

	}


}

dao方法：

package com.hc.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

import com.hc.entity.Area;
import com.hc.entity.City;
import com.hc.entity.Province;

public class HcDao {

	
	public List<Province> getAllPro() {
		List<Province> ml=new ArrayList<Province>();
		Connection con=BaseDao.getCon();
		PreparedStatement pre=null;
		ResultSet res=null;
		try {
			pre=con.prepareStatement("select * from hat_province");
			res=pre.executeQuery();
			while (res.next()) {
				Province p=new Province();
				p.setPid(res.getString(2));
				p.setPname(res.getString(3));
				ml.add(p);
			}
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		finally{
			BaseDao.myClose(con, pre, res);
		}
		return ml;
		
	}
	
	public List<City> getCityById(String father) {
		List<City> ml=new ArrayList<City>();
		Connection con=BaseDao.getCon();
		PreparedStatement pre=null;
		ResultSet res=null;
		try {
			pre=con.prepareStatement("select * from hat_city where father=?");
			pre.setString(1, father);
			res=pre.executeQuery();
			while (res.next()) {
				City p=new City();
				p.setCid(res.getString(2));
				p.setCname(res.getString(3));
				ml.add(p);
			}
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		finally{
			BaseDao.myClose(con, pre, res);
		}
		return ml;
		
	}
	
	public List<Area> getAreaById(String father) {
		List<Area> ml=new ArrayList<Area>();
		Connection con=BaseDao.getCon();
		PreparedStatement pre=null;
		ResultSet res=null;
		try {
			pre=con.prepareStatement("select * from hat_area where father=?");
			pre.setString(1, father);
			res=pre.executeQuery();
			while (res.next()) {
				Area p=new Area();
				p.setAname(res.getString(3));
				ml.add(p);
			}
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		finally{
			BaseDao.myClose(con, pre, res);
		}
		return ml;
		
	}
	
	
}

熟悉的感觉，但是这些都只是曾经的过往，框架才是主流！