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011-DataStream与MySql自定义sink和source(Java版)003

四、自定义sink

1.自定义sink

package code.book.stream.customsinkandsource.jdbc.java;import org.apache.flink.configuration.Configuration;import org.apache.flink.streaming.api.functions.sink.RichSinkFunction;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;public class StudentSinkToMysql extends RichSinkFunction<Student> {    private Connection connection = null;    private PreparedStatement ps = 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    public void open(Configuration parameters) throws Exception {        super.open(parameters);        String driver = "com.mysql.jdbc.Driver";        String url = "jdbc:mysql://qingcheng11:3306/flinktest";        String username = "root";        String password = "qingcheng";        //1.加载驱动        Class.forName(driver);        //2.创建连接        connection = DriverManager.getConnection(url, username, password);        String 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    public void invoke(Student student) throws Exception {        try {            //4.组装数据，执行插入操作            ps.setInt(1, student.getStuid());            ps.setString(2, student.getStuname());            ps.setString(3, student.getStuaddr());            ps.setString(4, student.getStusex());            ps.executeUpdate();        } catch (Exception e) {            e.printStackTrace();        }    }    @Override    public void close() throws Exception {        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.java;import org.apache.flink.streaming.api.datastream.DataStream;import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;public class StudentSinkToMysqlTest {    public static void main(String[] args) throws Exception {        //1.创建流执行环境        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();        //2.准备数据        DataStream<Student> students = env.fromElements(                new Student(11, "zhangsan", "beijing biejing", "female"),                new Student(12, "lisi", "tainjing tianjin", "male ")        );        //3.将数据写入到自定义的sink中（这里是mysql）        students.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。