第一步:
package com.qq.db;
import java.sql.*;
/*
* 封装一个数据库的工具类
* 通用的获取数据的方法
* 提高代码的高重用性
* */
public class DBunit {
private static final String url = "jdbc:mysql://localhost:3306/qqdb";
private static final String user = "root";
private static final String password = "6612";
//封装了一个公共的获取数据库的连接方法
public static Connection getConnection() {
Connection conn = null;
try {
//1.加载驱动类
Class.forName("com.mysql.jdbc.Driver");
//2.创建数据库的连接(提供url+用户名+密码),向java.sql.DriverManger请求并获取Connection对象
conn = DriverManager.getConnection(url,user,password);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return conn;
}
//封装一个查询语句
public static ResultSet getQueryResult(String sql) {
ResultSet rs = null;
try {
Connection conn = DBunit.getConnection();
Statement stat = conn.createStatement();
rs = stat.executeQuery(sql);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return rs;
}
}
第二步:测试
package com.qq;
//封装完之后用类名连接方式连接数据库
import java.sql.*;
import java.sql.DriverManager;
import com.qq.db.DBunit;;
public class TestDBC {
public static void main(String[] args) {
try {
Connection conn = DBunit.getConnection();
String sql = "select * from t_user";
ResultSet rs = DBunit.getQueryResult(sql);//3.2相当于游标
while(rs.next()) {//判断是否有下一行
System.out.println(rs.getInt("id")+"\t"+rs.getString("name"));//输出数据内容
}
rs.close();
conn.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}