java连接mysql

Love The Way You Lie 2021-09-25 03:58 406阅读 0赞

import java.sql.*;
    
    public class MySQLDemo { 
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        public void getConnect(){ 
            // MySQL 8.0 以下版本 - JDBC 驱动名及数据库 URL
            String JDBC_DRIVER = "com.mysql.jdbc.Driver";
            String DB_URL = "jdbc:mysql://localhost:3306/test_database";
            String USER = "root";
            String PASS = "root";
            try{ 
                Class.forName(JDBC_DRIVER);
                System.out.println("连接数据库");
                this.conn = DriverManager.getConnection(DB_URL,USER,PASS);
                System.out.println(" 实例化Statement对象...");
                this.stmt = this.conn.createStatement();
    
    
            }catch (Exception e){ 
                e.printStackTrace();
            }
    
        }
        public void closeConnect(){ 
            try{ 
                if(this.stmt!=null) this.stmt.close();
            }catch(SQLException se2){ 
            }// 什么都不做
            try{ 
                if(this.conn!=null) this.conn.close();
            }catch(SQLException se){ 
                se.printStackTrace();
            }
        }
    
    
    
        public static void main(String[] args) { 
    
            MySQLDemo mySQLDemo = new MySQLDemo();
            mySQLDemo.getConnect();
    
            try{ 
                mySQLDemo.rs = mySQLDemo.stmt.executeQuery("select * from t_user");
                while(mySQLDemo.rs.next()){ 
                    // 通过字段检索
                    int id  = mySQLDemo.rs.getInt("id");
                    String name = mySQLDemo.rs.getString("id");
                    String url = mySQLDemo.rs.getString("password");
    
                    // 输出数据
                    System.out.print("ID: " + id);
                    System.out.print(", 站点名称: " + name);
                    System.out.print(", 站点 URL: " + url);
                    System.out.print("\n");
                }
                mySQLDemo.rs.close();
                mySQLDemo.stmt.close();
                mySQLDemo.conn.close();
            }catch (Exception e){ 
                e.printStackTrace();
            } finally { 
                // 完成后关闭
                mySQLDemo.closeConnect();
            }
    
    
    
        }
    }