jdbc工具類的幾個版本

阿新 • • 發佈：2021-01-23

技術標籤：jdbc

jdbc工具類的3個版本

版本一

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

public class DemoJdbc {

	public static void main(String[] args) throws Exception {
		//1載入jdba驅動
			//Class.forName("com.mysql.jdbc.Driver");
			//2獲得連結
			Connection conn= 
 DriverManager.getConnection("jdbc:mysql://localhost:3306/newdb3", "root", "root");
//			System.out.println(c.getClass().getName());
			//3建立命令通道
			Statement sta = conn.createStatement();
			//4傳送命令
			sta.execute("create table mytb2(id int,name varchar(15))");
			//5回收資源 

			conn.close();
			System.out.println("over");
			
			
	}
	

}

版本二


import java.sql.Connection;
import java.sql.DriverManager;

public class DBUtils {
	public static Connection getConn() throws Exception {
		Connection conn = null;
		String driver = "com.mysql.jdbc.Driver";
		String url = 
 "jdbc:mysql://localhost:3306/newdb3";
		String user = "root";
		String password = "root";
		Class.forName(driver);
		conn = DriverManager.getConnection(url,user,password);
		
		return conn;
	}

版本三

import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.util.Properties;

public class DBUtils2 {
	public static Connection getConn() throws Exception {
		Connection conn = null;
		InputStream is = DBUtils2.class.getClassLoader()
									.getResourceAsStream("jdbc.properties");
		//建立讀取器物件
		Properties p = new Properties();
		//載入流檔案
		p.load(is);
		//從檔案中獲得資源
		String driver = p.getProperty("driver");
		String url = p.getProperty("url");
		String user = p.getProperty("user");
		String password = p.getProperty("password");
		Class.forName(driver);
		conn = DriverManager.getConnection(url,user,password);
		
		return conn;
	}

版本四

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

import org.apache.commons.dbcp.BasicDataSource;

public class DBUtils3 {
	
private static BasicDataSource  ds;

static {
	//建立讀取器
	Properties p = new Properties();
	//建立輸入流
	InputStream is= DBUtils3.class.getClassLoader().getResourceAsStream("jdbc.properties");
	try {
		//新增is 到讀取器
		p.load(is);
		
	} catch (IOException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
	//讀取資訊
	String driver = p.getProperty("driver");
	String url = p.getProperty("url");
	String user = p.getProperty("user");
	String password= p.getProperty("password");
	//為連線池設定連線資訊
	ds = new BasicDataSource();
	ds.setDriverClassName(driver);
	ds.setUrl(url);
	ds.setUsername(user);
	ds.setPassword(password);
	//設定初始連線數量
	ds.setInitialSize(3);
	//設定最大連線數量
	ds.setMaxActive(5);
}
public static Connection getConn() throws SQLException {
	Connection conn = ds.getConnection();
			//System.out.println(conn);
	return conn;
}