jdbc 操作步骤

package org.db;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class DBConn {
    
//    public final static String URL = "jdbc:mysql://localhost:3306/test?useSSL=false";
    public final static String URL = "jdbc:mysql://localhost:3306/test?characterEncoding=utf8"; //可以指定jdbc编码方式
    public final static String USERNAME = "root";
    public final static String PASSWORD = "000000";
    public final static String DRIVER = "com.mysql.jdbc.Driver";
    
    public static Connection conn;
    public static Connection getConn(){
        try {
            Class.forName(DRIVER);
            conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
            if (conn!=null) {
                System.out.println("连接成功");
            }
            return conn;
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("连接失败");
            return null;
        }
    }
    public static void closeConn(){
        try {
            if(conn!=null){
                conn.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

package org.test;

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

import org.db.DBConn;
import org.model.Login;

public class test {

    public static void main(String[] args) {
        Connection conn = DBConn.getConn();
        if (conn!=null) {
            System.out.println("连接成功");
            try {
                conn = DBConn.getConn();
                String sql = "select id,name,password,role from mbook where name=? and password=?";
                PreparedStatement ps = conn.prepareStatement(sql);
                ps.setString(1,"张三");
                ps.setString(2,"000000");
                ResultSet rs = ps.executeQuery();
                        
                    while (rs.next()) {
                    Login login = new Login();
                    login.setId(rs.getInt(1));
                    login.setName(rs.getString(2));
                    login.setPassword(rs.getString(3));
                    login.setRole(rs.getBoolean(4));
                    System.out.println("得到数据："+login);    
                    }
            } catch (SQLException e) {
                e.printStackTrace();
            }finally{
                DBConn.closeConn();
            }            
        }
    }
}