java使用jdbc连接数据库简单实例

package com.tr.jdbc;

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

import org.apache.commons.dbcp2.BasicDataSource;

public class CollectionFactory {

 private final static String dbDriver = "com.mysql.jdbc.Driver";
 private final static String dbUrl="jdbc:mysql://localhost:3306/xtest?useUnicode=true&characterEncoding=UTF-8" ;
 private final static String dbUser="root";
 private final static String dbpwd="root";

 private static BasicDataSource dataSource;
 //创建dbcp的简单数据源并初始化相关属性
 static{
  dataSource = new BasicDataSource();
  dataSource.setDriverClassName(dbDriver);
  dataSource.setUrl(dbUrl);
  dataSource.setUsername(dbUser);
  dataSource.setPassword(dbpwd);

  //指定数据库连接池初始化连接数
  dataSource.setInitialSize(10);
  //设定同时向数据库申请的最大连接数
  dataSource.setMaxTotal(50);
  //设置连接池中保持的最少连接数量
  dataSource.setMinIdle(5);
  //其他属相...参考Apache的公开文档
 }
 //创建数据库连接对象--并且多线程并发处理(注意Connection导的是Java.sql的包)
 public static synchronized Connection creatConnection(){
  Connection conn = null;
  if(dataSource!=null&&!dataSource.isClosed()){
   try {
    conn = dataSource.getConnection();
   } catch (SQLException e) {

    e.printStackTrace();
   }
  }
  return conn;

 }

 public static void main(String[] args) {
  String sql = "select * from s_t_user";
  Connection conn = creatConnection();
  Statement statement = null;
  ResultSet resultSet = null;
  try {
   statement = conn.createStatement();
   resultSet= statement.executeQuery(sql);
   int row = 0;
   while(resultSet.next()){
    row++;
    System.out.println("记录行"+row+"col2:"+resultSet.getString(2));
    }
  } catch (SQLException e) {
   e.printStackTrace();
  }finally {
   if (conn!=null) {
    try {
     conn.close();
    } catch (SQLException e) {  
     e.printStackTrace();
    }
   }
  }

 }

}