Scala之Demo1

1.创建Connection的object，在scala里面称为单例对象

package com.test
import java.sql.DriverManager
import java.sql.Connection

object SingleMySqlConn {

  private var driver = "com.mysql.jdbc.Driver"
  private var url = "jdbc:mysql://localhost/bms"
  private var connection: Connection = null;

  def getConnection(username: String, password: String): Connection = {

    if (connection == null) {

      try {
       
        Class.forName(driver)
        connection = DriverManager.getConnection(url, username, password)

        connection
      } 
      catch{
        
        case e=>e.printStackTrace()
        null
      }

    } else {

      connection
    }

  }
}

2.客户端调用连接MySQL单例对象的方法

package com.test
import java.sql.DriverManager
import java.sql.Connection

object ScalaMySql {

  def main(args: Array[String]): Unit = {

   
    val connection = SingleMySqlConn.getConnection("root", "123")

    if (connection != null) {

      val statement = connection.createStatement()
      val resultSet = statement.executeQuery("SELECT * FROM bms_appuser")
      while (resultSet.next()) {
        val userName = resultSet.getString("userName")
        val userCard = resultSet.getString("userCard")
        println("userName, <span style="font-family: Arial, Helvetica, sans-serif;">userCard </span>= " + userName + ", " + userCard)
      }
      connection.close()
    }
    
  }
}

3.简单测试结果

</pre><pre name="code" class="java">userName, userCard = zhao, XSJKLKL
userName, userCard = cui, <span style="font-family: Arial, Helvetica, sans-serif;">XSJKLKK</span>