数据库 基础连接 JAVA

 

 

import java.sql.*;public class DBTest2{String url = "jdbc:mysql://localhost:3306/";String user = "root";String passwd = "root";public DBTest2()throws ClassNotFoundException{Class.forName("com.mysql.jdbc.Driver");}public static void main(String[] args){}} 

 

 

import java.io.*;import java.sql.*;public class ConnectionDemo{public static void main(String[] args){String sql1 = "select * from a1";String sql2 = "insert into a1(aa,bb)values(null,'aaa')";try{DBSource dbsource = new SimpleDBSource();Connection conn = dbsource.getConnection();Statement stmt = conn.createStatement();ResultSet rs = stmt.executeQuery(sql1);ResultSetMetaData rmeta = rs.getMetaData();int numColumns = rmeta.getColumnCount();System.out.println(numColumns);//rs.next();//System.out.println(rs.getString(1));//System.out.println();while(rs.next()){//rs.next();//String str1 = rs.getString(0);//int a1 = rs.getInt(0);//System.out.println(str1);//System.out.println(a1);for(int i = 0;i<numColumns;i++){String sTemp = rs.getString(i+1);System.out.println(sTemp + " ");}System.out.println();}for(int i=0;i<10000;i++){stmt.executeUpdate(sql2);}if(!conn.isClosed()){System.out.println("数据库连接已开启");}dbsource.closeConnection(conn);if(conn.isClosed()){System.out.println("数据库连接已关闭");}/*}catch(IOException e){e.printStackTrace();*/}catch(ClassNotFoundException e){e.printStackTrace();}catch(SQLException e){e.printStackTrace();}}}import java.sql.*;public interface DBSource{public ConnectiongetConnection()throws SQLException;public voidcloseConnection(Connection conn)throws SQLException;}import java.util.*;import java.sql.*;import java.io.*;public class SimpleDBSource implements DBSource{String url;String user;String passwd;public SimpleDBSource()throws ClassNotFoundException{url = "jdbc:mysql://localhost:3306/demo";user = "root";passwd = "root";Class.forName("com.mysql.jdbc.Driver");}public ConnectiongetConnection()throws SQLException{return DriverManager.getConnection(url,user,passwd);}public voidcloseConnection(Connection conn)throws SQLException{conn.close();}}