Java数据库连接技术

使用mysql作为开发数据库，创建user表。创表语句如下：

create database learn;
use learn;
CREATE TABLE user(id INT PRIMARY KEY AUTO_INCREMENT, NAME VARCHAR(32), age INT);
INSERT INTO user(NAME, age) VALUES('coshaho', 29);
INSERT INTO user(NAME, age) VALUES('cauchy', 29);

一、使用Java直接连接mysql

1、添加mysql驱动

      <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.13</version>
    </dependency>

2、连接代码如下

package com.coshaho.jdbc;

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

/**
 * Java连接数据库
 * @author coshaho
 */
public class MysqlConnector 
{
    public static void main(String[] args)
    {
        Connection con = null;
        Statement statement = null;
        ResultSet rs = null;
        String driver = "com.mysql.cj.jdbc.Driver";
        String url = "jdbc:mysql://132.232.35.119:3306/learn";
        String user = "root";
        String password = "root";
        try 
        {
            Class.forName(driver);
            // 使用DriverManager获取连接
            con = DriverManager.getConnection(url,user,password);
            // 创建statement类对象，用来执行SQL语句！！
            statement = con.createStatement();
            String sql = "select * from user";
            rs = statement.executeQuery(sql);
            System.out.println("name" + "\t" + "age");  
             
            int age = 0;
            String name = null;
            while(rs.next())
            {
                // ResultSet获取返回值时，列名不区分大小写
                name = rs.getString("nAme");
                age = rs.getInt("age");
                System.out.println(name + "\t" + age);
            }
        } 
        catch(ClassNotFoundException e) 
        {   
            e.printStackTrace();   
        } 
        catch(SQLException e) 
        {
            e.printStackTrace();  
        }
        catch (Exception e) 
        {
            e.printStackTrace();
        }
        finally
        {
            // 从内向外释放连接
            try 
            {
                if(null != rs)
                {
                    rs.close();
                }
            } 
            catch (SQLException e) 
            {
                e.printStackTrace();
            }
            try 
            {
                if(null != statement)
                {
                    statement.close();
                }
            } 
            catch (SQLException e) 
            {
                e.printStackTrace();
            }
            try 
            {
                if(null != con)
                {
                    con.close();
                }
            } 
            catch (SQLException e) 
            {
                e.printStackTrace();
            }
        }
    }
}

3、执行效果