Java连接MySQl数据库实现代码

1. 获取数据库连接和查询代码

package connectionmysql;

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

public class ConnectionMysql {

    //数据库连接用户名
    private String userName = "root";
    
    //数据库连接密码
    private String pwd = "910214";
    
    //设置数据库
    private String database = "jsp";
    
    //设置jdbc驱动
    private String dbDriver = "com.mysql.jdbc.Driver";
    
    //设置数据库连接URL
    private String dbConnect = "jdbc:mysql://localhost:3306/"+database;
    
    //连接变量
    private Connection conn = null;
    
    private Statement stmt = null;
    
    ResultSet rs = null;
    
    
    /*数据库驱动注册*/
    public ConnectionMysql()
    {
        try{
            Class.forName(dbDriver);
        }
        catch(Exception ex)
        {
            System.out.println("连接失败: "+ex.getMessage());
        }
    }
    
    /*建立数据库连接及其数据查询*/
    public ResultSet executeQuery(String sql) throws SQLException{
        rs = null;
        try{
            conn = DriverManager.getConnection(dbConnect, userName, pwd);
            stmt = conn.createStatement();
            rs = stmt.executeQuery(sql);
        }catch(Exception ex)
        {
            System.out.println("连接失败: "+ex.getMessage());
        }
//        finally{
//            //关闭数据库连接
//            stmt.close();
//            conn.close();
//        }
        return rs;
    }
    
    /*建立数据库连接和数据库查询*/
    public void excuteUpdate(String sql) throws SQLException
    {
        stmt = null;
        try{
            //连接数据库
            conn = DriverManager.getConnection(dbConnect, userName, pwd);
            stmt = conn.createStatement();
            stmt.executeUpdate(sql);
        }catch(Exception ex){
            //手动抛出异常
            throw new SQLException(ex.getMessage());
        }
//        finally{
//            stmt.close();
//            conn.close();
//        }
    }
    
    /*
     * 考虑数据库的性能问题，需要释放数据库资源，因此关闭方法
     */
    //关闭陈述语句
    public void CloseStmt()
    {
        try{
            stmt.close();
        }catch(SQLException ex){
            System.out.println("关闭数据库失败: "+ex.getMessage());
        }
    }
    //关闭连接
    public void CloseConn(){
        try{
            conn.close();
        }catch(SQLException ex){
            System.out.println("关闭连接失败: "+ex.getMessage());
        }
    }
    
    
}

2.测试代码

package connectionmysql;

import java.sql.ResultSet;
import java.sql.SQLException;

public class TestMysqlConnection {

    /**
     * 运行程序测试
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        ConnectionMysql conMysql = new ConnectionMysql();
        //查询数据库SQL语句
        String sql = "select username,password from userlogin";
        
        try{
            //返回查询结果集
            ResultSet rs = conMysql.executeQuery(sql);
            //打印查询数据
            if(rs.next()){
                String username = rs.getString(1);
                String password = rs.getString(2);
                System.out.println("用户名: "+username);
                System.out.println("密    码 : "+password);
//                System.out.println(rs.getString(2));
            }
        }catch(SQLException ex){
            System.out.println("查询失败: "+ex.getMessage());
        }finally{
            //关闭数据库连接
            conMysql.CloseStmt();
            conMysql.CloseConn();
        }
    }

}