jdbc连接Oracle

public static void main(String[] args) {
        //声明连接对象、执行sql对象、结果集对象
        Connection conn = null;
        PreparedStatement pre = null;
        ResultSet results  = null;
        //添加jar驱动
        try{
            //注册驱动
            Class.forName("oracle.jdbc.driver.OracleDriver");
            //获取连接数据库对象
            String url = "jdbc:oracle:thin:@127.0.0.1:1521:orcl";
            String name = "SCOTT";
            String pwd = "SCOTT";
            //DriverManage初始化时会扫描到注册的Driver实例
            conn = DriverManager.getConnection(url,name,pwd);
            System.out.println("连接成功");
            //定义要执行的sql
            String sql = "SELECT * FROM SCOTT.STUDENT";
            //获取执行sql对象,预编译sql，进行缓存
            pre = conn.prepareStatement(sql);
            //执行SQL并返回结果集
            results = pre.executeQuery();
            System.out.println("执行成功");
            while(results.next()){
                System.out.println("学生名:"+results.getString("STUNAME"));
            }
        }catch (Exception  e){
            e.printStackTrace();
        }finally {
            try {
                if (results != null)
                    results.close();
                if (pre != null)
                    pre.close();
                if (conn != null)
                    conn.close();
                System.out.println("数据库连接已关闭！");
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
}

//增删改查

package dao;

import entity.StuEntity;
import oracle.jdbc.driver.utils.StringUtils;

import java.sql.*;

public class StuDao {
    //声明连接对象、执行sql对象、结果集对象
    private static Connection conn = null;
    private static PreparedStatement pre = null;
    private static ResultSet results  = null;

    public Connection getConnection() throws SQLException {
        try {
            //注册驱动
            Class.forName("oracle.jdbc.driver.OracleDriver");
            //获取连接数据库对象
            String url = "jdbc:oracle:thin:@127.0.0.1:1521:orcl";
            String name = "SCOTT";
            String pwd = "cpp123456";
            //DriverManage初始化时会扫描到注册的Driver实例
            conn = DriverManager.getConnection(url,name,pwd);
            System.out.println("连接成功");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        return conn;
    }

    public ResultSet selectStu()throws SQLException {
        //定义要执行的sql
        String sql = "SELECT * FROM SCOTT.STUDENT";
        //获取执行sql对象,预编译SQL，减少sql执行
        pre = conn.prepareStatement(sql);
        //执行SQL并返回结果集
        results = pre.executeQuery();
        System.out.println("执行select成功");
        return results;
    }

    public void deleteStu(String stuId) throws SQLException {
        //定义要执行的sql
        String sql = "delete from SCOTT.STUDENT where STUID=?";
        //获取执行sql对象,预编译SQL，减少sql执行
        pre = conn.prepareStatement(sql);
        //传参
        pre.setString(1,stuId);
        //执行SQL返回受影响行数
        int i=pre.executeUpdate();
        System.out.println("执行delete,成功删除"+i+"条数据");
    }

    public void addStu(StuEntity stuEntity)throws SQLException {
        //定义要执行的sql
        String sql = "insert into SCOTT.STUDENT values(?,?,?,?,?)";
        //获取执行sql对象,预编译SQL，减少sql执行
        pre = conn.prepareStatement(sql);
        //传参
        pre.setString(1,stuEntity.getStuId());
        pre.setString(2,stuEntity.getStuName());
        pre.setString(3,stuEntity.getStuAge());
        pre.setString(4,stuEntity.getStuSex());
        pre.setString(5,stuEntity.getStuAddress());
        //执行SQL返回true或false
        pre.execute();
        System.out.println("执行add成功");
    }

    public void updateStu(StuEntity stuEntity)throws SQLException {
        //定义要执行的sql
        String sql = "update SCOTT.STUDENT"+
                " set STUNAME=?,STUAGE=?,STUSEX=?,STUADDRESS=?"+
                " where STUID=?";
        //获取执行sql对象,预编译SQL，减少sql执行
        pre = conn.prepareStatement(sql);
        //传参
        pre.setString(1,stuEntity.getStuName());
        pre.setString(2,stuEntity.getStuAge());
        pre.setString(3,stuEntity.getStuSex());
        pre.setString(4,stuEntity.getStuAddress());
        pre.setString(5,stuEntity.getStuId());
        //执行SQL返回受影响行数
        int i=pre.executeUpdate();
        System.out.println("执行update,成功更新"+i+"条数据");
    }
}