1、调试服务器上的代码是否与数据库的数据是否是联通的

  DBAccess.java

package com.javaxl.p1.utils;

import java.io.InputStream;
import java.io.PrintStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

public class DBAccess
{
  private static String driver;
  private static String url;
  private static String user;
  private static String password;
  
  static
  {
    try
    {
      InputStream is = DBAccess.class.getResourceAsStream("/jdbc.properties");
      
      Properties properties = new Properties();
      properties.load(is);
      
      driver = properties.getProperty("jdbc.driver");
      url = properties.getProperty("jdbc.url");
      user = properties.getProperty("jdbc.username");
      password = properties.getProperty("jdbc.password");
      
      Class.forName(driver);
    }
    catch (Exception e)
    {
      e.printStackTrace();
      throw new RuntimeException(e);
    }
  }
  
  public static Connection getConnection()
  {
    try
    {
      return DriverManager.getConnection(url, user, password);
    }
    catch (SQLException e)
    {
      e.printStackTrace();
      throw new RuntimeException(e);
    }
  }
  
  public static void close(ResultSet rs)
  {
    if (null != rs) {
      try
      {
        rs.close();
      }
      catch (SQLException e)
      {
        e.printStackTrace();
        throw new RuntimeException(e);
      }
    }
  }
  
  public static void close(Statement stmt)
  {
    if (null != stmt) {
      try
      {
        stmt.close();
      }
      catch (SQLException e)
      {
        e.printStackTrace();
        throw new RuntimeException(e);
      }
    }
  }
  
  public static void close(Connection conn)
  {
    if (null != conn) {
      try
      {
        conn.close();
      }
      catch (SQLException e)
      {
        e.printStackTrace();
        throw new RuntimeException(e);
      }
    }
  }
  
  public static void close(Connection conn, Statement stmt, ResultSet rs)
  {
    close(rs);
    close(stmt);
    close(conn);
  }
  
  public static boolean isOracle()
  {
    return "oracle.jdbc.driver.OracleDriver".equals(driver);
  }
  
  public static boolean isSQLServer()
  {
    return "com.microsoft.sqlserver.jdbc.SQLServerDriver".equals(driver);
  }
  
  public static boolean isMysql()
  {
    return "com.mysql.jdbc.Driver".equals(driver);
  }
  
  public static void main(String[] args)
  {
    Connection conn = getConnection();
    close(conn);
    System.out.println("isOracle：" + isOracle());
    System.out.println("isSQLServer：" + isSQLServer());
    System.out.println("isMysql：" + isMysql());
    System.out.println("数据库连接|关闭成功");
  }
}

  可以将DBAccess.java文件放入DBAccess.class所在的文件夹，放入之前去掉Java文件中package导包；

  再将jdbc.properties文件导入与DBAccess.java同文件夹下；

  用javac命令编译DBAccess.java文件

javac DBAccess.java

  用java命令运行DBAccess.class文件

java DBAccess

  如此就可以查看connection对象是否是空的了