package com.edu.cec;
import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;
public class DBsql { String username; String password; String url ; String driver; Connection cn; Statement stmt; String sql; ResultSet rs; public DBsql() { username = "root"; // root为数据库用户名 password = "root"; // 定义密码字符串 // 定义数据库连接字 url = "jdbc:mysql://localhost:3306/pdw"; // pdw为数据库名字 driver = "com.mysql.jdbc.Driver"; try { Class.forName(driver); cn = DriverManager.getConnection(url, username, password); stmt = cn.createStatement(); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } //查询率的问题 public ResultSet queryRate(String sql) { try { rs = stmt.executeQuery(sql); } catch (SQLException e) { e.printStackTrace(); } return rs; } //修改数据 public void updateS(String sql) { try { int count=stmt.executeUpdate(sql); if (count >0) { System.out.println("操作成功"); } else { System.out.println("操作失败"); } } catch (SQLException e) { e.printStackTrace(); } } //根据字段查询结果 public ResultSet getResult_From_Field(String sql) { try { rs = stmt.executeQuery(sql); } catch (SQLException e) { e.printStackTrace(); } return rs; } //查询 public ResultSet getResultS(String sql) { try { rs = stmt.executeQuery(sql); } catch (SQLException e) { e.printStackTrace(); } return rs; } //插入 public void insertS(String sql) { try { boolean isInsert=stmt.execute(sql); } catch (SQLException e) { e.printStackTrace(); } } //删除 public void deleteS(String sql) { try { int count=stmt.executeUpdate(sql); if (count >0) { System.out.println("操作成功"); } else { System.out.println("操作失败"); }
} catch (SQLException e) { e.printStackTrace(); } }}
