连接MySql数据库和查询数据

1、在项目下的src路径下进行创建JavaBean,用于连接数据库。

package com.bat;

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

public class DataHe {
    String driver= "com.mysql.jdbc.Driver";
    String url= "jdbc:mysql://localhost:3306/hu";
    String user="root";
    String password="qwe123";
    
    public Connection getConn(){ 
        Connection conn=null;
        try {
               //1、加载驱动
            Class.forName(driver);
             //2、创建连接
             conn = DriverManager.getConnection(url, user, password);
            
        } catch (ClassNotFoundException | SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
          return conn;  
    }
    
    
    public void  closeAl(ResultSet rs,Statement stmt,Connection conn){
        
        if(rs!=null){
            try {
                rs.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        if(stmt!=null){
          try {
            stmt.close();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        }
        if(conn!=null){
            try {
                conn.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        
    } 
}

2、在创建jsp页面进行渲染数据库中的数据（进行查询操作）。

<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>



  
    
    
    
    
    
        
    
    
    
  
  
  
 
    
     <% 
     try{
     Connection con=null;
     String sql="select * from student";
     DataHe data =new  DataHe();
      
     con=data.getConn();
    Statement stmt=con.createStatement();
    ResultSet rs=stmt.executeQuery(sql);  
    while(rs.next()){
  %>
    

    

    
The order number
    
Student name
    
Student age
    
Student deploy
    
telephone
    
qq'number
    

    
<%=rs.getInt("id") %>
    
<%=rs.getString("stu_name") %>
    
<%=rs.getString("stu_age") %>
    
<%=rs.getString("stu_deploy") %>
    
<%=rs.getString("telephone") %>
    
<%=rs.getString("qq") %>
    
   
     
    <%
   
    
    data.closeAl(rs, stmt, con);
      } 
      } catch(Exception e){System.out.print("出现错误");}
      
    %>
  

3、下面的这个代码是直接单独用jsp界面实现的查询数据库数据的功能。

  
    

    
    
        
    
    
    

  
  
  
  <%


String driver = "com.mysql.jdbc.Driver";

// URL指向要访问的数据库名test1

String url = "jdbc:mysql://127.0.0.1:3306/hu";

// MySQL配置时的用户名

String user = "root";

// Java连接MySQL配置时的密码

String password = "qwe123";

try {

// 1 加载驱动程序

Class.forName(driver);

// 2 连接数据库

Connection conn = DriverManager.getConnection(url, user, password);

// 3 用来执行SQL语句

Statement statement = conn.createStatement();

// 要执行的SQL语句

String sql = "select * from student";

ResultSet rs = statement.executeQuery(sql);
String name = null;
String mima=null;
while (rs.next()) {
name = rs.getString("stu_age");
mima = rs.getString("stu_name");
out.println(name+"\t"+mima);
}
rs.close();
conn.close();
} catch (ClassNotFoundException e) {
System.out.println("Sorry,can`t find the Driver!");
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}

%>