java使用jdbc连接数据库工具类和jdbc连接mysql数据示例

package com.lanp.ajax.db;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

/**
 * 连接数据库的工具类,被定义成不可继承且是私有访问
 */
public final class DBUtils {
 private static String url = "jdbc:mysql://localhost:3306/mydb";
 private static String user = "root";
 private static String psw = "root";

 private static  Connection conn;

 static {
  try {
   Class.forName("com.mysql.jdbc.Driver");
  } catch (ClassNotFoundException e) {
   e.printStackTrace();
   throw new RuntimeException(e);
  }
 }

 private DBUtils() {

 }

 /**
  * 获取数据库的连接
  * @return conn
  */
 public static Connection getConnection() {
  if(null == conn) {
   try {
    conn = DriverManager.getConnection(url, user, psw);
   } catch (SQLException e) {
    e.printStackTrace();
    throw new RuntimeException(e);
   }
  }
  return conn;
 }

 /**
  * 释放资源
  * @param conn
  * @param pstmt
  * @param rs
  */
 public static void closeResources(Connection conn,PreparedStatement pstmt,ResultSet rs) {
  if(null != rs) {
   try {
    rs.close();
   } catch (SQLException e) {
    e.printStackTrace();
    throw new RuntimeException(e);
   } finally {
    if(null != pstmt) {
     try {
      pstmt.close();
     } catch (SQLException e) {
      e.printStackTrace();
      throw new RuntimeException(e);
     } finally {
      if(null != conn) {
       try {
        conn.close();
       } catch (SQLException e) {
        e.printStackTrace();
        throw new RuntimeException(e);
       }
      }
     }
    }
   }
  }
 }
}

import java.sql.*;  

 public class ConnectMysql {  
    public static void main(String[] args) {  
        String driver = "com.mysql.jdbc.Driver";  
        String url = "jdbc:mysql://192.168.1.112:3306/linksystem";  
        String user = "root";  
        String password = "blog.micxp.com";  
        try {  
            Class.forName(driver);  
            Connection conn = DriverManager.getConnection(url, user, password);  
            if (!conn.isClosed()) {  
                System.out.println("Succeeded connecting to the Database!");  
                Statement statement = conn.createStatement();  
                String sql = "select * from flink_list";  
                ResultSet rs = statement.executeQuery(sql);  
                String name;  
                while (rs.next()) {  

                    name = rs.getString("link_name");  
                    System.out.println(name);  
                }  
            }  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
    }  
}