云星数据---Apache Flink实战系列(精品版)】：Flink流处理API详解与编程实战008-DataStream与MySql自定义sink和source(Scala版)003

四、自定义sink

1.自定义sink

package code.book.stream.customsinkandsource.jdbc.scalaimport java.sql.{Connection, DriverManager, PreparedStatement}import org.apache.flink.configuration.Configurationimport org.apache.flink.streaming.api.functions.sink.RichSinkFunctionclass StudentSinkToMysql extends RichSinkFunction[Student] {  private var connection: Connection = null  private var ps: PreparedStatement = null  /**    * 一、open()方法中建立连接，这样不用每次invoke的时候都要建立连接和释放连接。    */  override def open(parameters: Configuration): Unit = {    super.open(parameters)    val driver = "com.mysql.jdbc.Driver"    val url = "jdbc:mysql://qingcheng11:3306/flinktest"    val username = "root"    val password = "qingcheng"    //1.加载驱动    Class.forName(driver)    //2.创建连接    connection = DriverManager.getConnection(url, username, password)    val sql = "insert into Student(stuid,stuname,stuaddr,stusex)values(?,?,?,?);"    //3.获得执行语句    ps = connection.prepareStatement(sql)  }  /**    * 二、每个元素的插入都要调用一次invoke()方法，这里主要进行插入操作    */  override def invoke(stu: Student): Unit = {    try {      //4.组装数据，执行插入操作      ps.setInt(1, stu.stuid)      ps.setString(2, stu.stuname)      ps.setString(3, stu.stuaddr)      ps.setString(4, stu.stusex)      ps.executeUpdate()    } catch {      case e: Exception => println(e.getMessage)    }  }  /**    * 三、 程序执行完毕就可以进行，关闭连接和释放资源的动作了    */  override def close(): Unit = {    super.close()    //5.关闭连接和释放资源    if (connection != null) {      connection.close()    }    if (ps != null) {      ps.close()    }  }}

2.sink测试程序

package code.book.stream.customsinkandsource.jdbc.scalaimport org.apache.flink.streaming.api.scala.{StreamExecutionEnvironment, _}object StudentSinkToMysqlTest {  def main(args: Array[String]): Unit = {    //1.创建流执行环境    val env = StreamExecutionEnvironment.getExecutionEnvironment    //2.准备数据    val dataStream:DataStream[Student] = env.fromElements(      Student(5, "dahua", "beijing biejing", "female"),      Student(6, "daming", "tainjing tianjin", "male "),      Student(7, "daqiang ", "shanghai shanghai", "female")    )    //3.将数据写入到自定义的sink中（这里是mysql）    dataStream.addSink(new StudentSinkToMysql)    //4.触发流执行    env.execute()  }}

3.sink测试效果

在mysql中能够查询到，flink写入的数据。