[javaEE] JDBC快速入门

Posted 2020-08-03 陶士涵的菜地

JDBC：Java Data Base Connectivity java数据库连接

 

1.组成JDBC的两个包：主要是接口

java.sql javax.sql

2.相应JDBC的数据库实现

 

在tomcat的目录下面添加mysql-connector-java-5.0.8-bin.jar这个数据库驱动包

 

package com.tsh.web;

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 */
public class DbServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     */
    public DbServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     */
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {

        try {
            // 注册数据库驱动
            //DriverManager.registerDriver(new Driver());
            //使用反射的方式
            Class.forName("com.mysql.jdbc.Driver");
            //获取数据库连接，导包的时候，注意要导java.sql下的，面向接口编程
            Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/java","root","root");
            //获取传输器对象
            Statement statement=conn.createStatement();
            //获取结果集对象
            ResultSet resultSet=statement.executeQuery("select * from user");
            //遍历
            while(resultSet.next()){
                String username=resultSet.getString("username");
                response.getWriter().write(username);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     */
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
    }

}