简单的JAVA实现连接数据库并且验证登陆

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package three;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Scanner;

public  class UserDaoImpl {
	   static String Driver = "com.mysql.jdbc.Driver";
	   static String    url = "jdbc:mysql://localhost:3306/net1";
	   static String   root = "root";
	   static String     ps = "123456";
	
	Connection coon = null;
	Statement st = null;
	ResultSet rs = null;
	
	
	//查询医生
	public void queryDocter(String dname,String dpassword)  {
		
		String sql = "SELECT * FROM doctory where dname='"+dname+"'&& dpassword="+"'"+dpassword+"'";

		
		
			
			try {
				coon = DriverManager.getConnection(url,root,ps);
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			
			try {
				st = coon.createStatement();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			try {
				ResultSet 	 rs = st.executeQuery(sql);
				if (rs.next()){
					System.out.println("医生的名字是"+rs.getString("dname"));
				}else{
					System.out.println("用户账号不存在或者密码错误");
				}
				
				
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
	}
	public static void main(String[]args){
		Scanner input = new Scanner(System.in);
		
		System.out.println("请输入医生账号:");
		String dname = input.next();
		
		System.out.println("请输入医生密码:");
		String dpassword = input.next();
		
		new UserDaoImpl().queryDocter(dname,dpassword);
		
	}
	
}
	
	
	
			
		
	


	

记住需要加载数据库的驱动包

mysql-connector-java-5.1.25-bin.jar

创建数据库代码

CREATE DATABASE net1; 
USE `net1`;

CREATE TABLE `doctory` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `dname` varchar(4) DEFAULT NULL,
  `dpassword` varchar(20) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;