Flink教程（08）- Flink批流一体API（Sink示例）

/**
 * @author : YangLinWei
 * @createTime: 2022/3/7 4:29 下午
 * <p>
 * 1.ds.print 直接输出到控制台
 * 2.ds.printToErr() 直接输出到控制台,用红色
 * 3.ds.collect 将分布式数据收集为本地集合
 * 4.ds.setParallelism(1).writeAsText("本地/HDFS的path",WriteMode.OVERWRITE)
 */
public class SinkDemo01 {
    public static void main(String[] args) throws Exception {
        //1.env
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        //2.source
        //DataStream<String> ds = env.fromElements("hadoop", "flink");
        DataStream<String> ds = env.readTextFile("data/input/words.txt");
        //3.transformation
        //4.sink
        ds.print();
        ds.printToErr();
        ds.writeAsText("data/output/test", FileSystem.WriteMode.OVERWRITE).setParallelism(2);
        //注意:
        //Parallelism=1为文件
        //Parallelism>1为文件夹
        //5.execute
        env.execute();
    }
}

/**
 * sink-custom
 *
 * @author : YangLinWei
 * @createTime: 2022/3/7 4:34 下午
 */
public class SinkDemo02 {
    public static void main(String[] args) throws Exception {
        //1.env
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        //2.Source
        DataStream<Student> studentDS = env.fromElements(new Student(null, "jim", 18));
        //3.Transformation
        //4.Sink
        studentDS.addSink(new MySQLSink());
        //5.execute
        env.execute();
    }
    @Data
    @NoArgsConstructor
    @AllArgsConstructor
    public static class Student {
        private Integer id;
        private String name;
        private Integer age;
    }
    public static class MySQLSink extends RichSinkFunction<Student> {
        private Connection conn = null;
        private PreparedStatement ps = null;
        @Override
        public void open(Configuration parameters) throws Exception {
            //加载驱动,开启连接
            //Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/big_data", "root", "123456");
            String sql = "INSERT INTO `t_student` (`id`, `name`, `age`) VALUES (null, ?, ?)";
            ps = conn.prepareStatement(sql);
        }
        @Override
        public void invoke(Student value, Context context) throws Exception {
            //给ps中的?设置具体值
            ps.setString(1, value.getName());
            ps.setInt(2, value.getAge());
            //执行sql
            ps.executeUpdate();
        }
        @Override
        public void close() throws Exception {
            if (conn != null) conn.close();
            if (ps != null) ps.close();
        }
    }
}