实现Java mysql 数据通过flink倒入es

1. 流程概述

整个流程大致分为以下几个步骤：

  1. 连接到MySQL数据库，读取数据
  2. 将读取到的数据转换成流(Stream)
  3. 对流进行处理和转换
  4. 将处理后的数据写入Elasticsearch

下面将逐步讲解每个步骤需要做的事情和相应的代码实现。

2. 连接到MySQL数据库，读取数据

首先，我们需要连接到MySQL数据库并读取数据。这可以通过以下代码实现：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

public class MySQLReader {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/database_name";
        String user = "username";
        String password = "password";

        try {
            Connection conn = DriverManager.getConnection(url, user, password);
            PreparedStatement stmt = conn.prepareStatement("SELECT * FROM table_name");
            ResultSet rs = stmt.executeQuery();

            while (rs.next()) {
                // 读取数据并进行处理
            }

            rs.close();
            stmt.close();
            conn.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

其中，url是MySQL数据库的连接地址，user和password是数据库的用户名和密码，table_name是要读取的表名。

3. 将读取到的数据转换成流(Stream)

接下来，我们需要将从MySQL数据库中读取到的数据转换成可以在Flink中处理的流(Stream)。这可以通过以下代码实现：

import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.api.java.tuple.Tuple;

public class StreamConverter {
    public static void main(String[] args) throws Exception {
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        DataStream<Tuple> stream = env.addSource(new MySQLSource());

        // 对流进行处理和转换

        env.execute("Flink Streaming Job");
    }
}

其中，我们使用StreamExecutionEnvironment创建了一个流处理环境，并使用addSource方法将MySQLSource作为数据源。

4. 对流进行处理和转换

在这一步中，我们可以对读取到的流进行各种处理和转换，例如过滤数据、转换数据类型等。这可以根据具体业务需求进行具体操作。

5. 将处理后的数据写入Elasticsearch

最后，我们需要将处理后的数据写入Elasticsearch。这可以通过以下代码实现：

import org.apache.flink.streaming.connectors.elasticsearch7.ElasticsearchSink;
import org.apache.http.HttpHost;
import org.apache.flink.api.common.functions.RuntimeContext;
import org.apache.flink.api.common.serialization.SimpleStringEncoder;
import org.apache.flink.api.common.serialization.SimpleStringSchema;
import org.apache.flink.core.fs.Path;
import org.apache.flink.streaming.api.checkpoint.CheckpointedFunction;
import org.apache.flink.streaming.api.functions.sink.filesystem.StreamingFileSink;
import org.apache.flink.streaming.api.functions.sink.filesystem.bucketassigners.DateTimeBucketAssigner;
import org.apache.flink.streaming.api.functions.sink.filesystem.rollingpolicies.DefaultRollingPolicy;
import org.apache.flink.streaming.api.functions.sink.filesystem.rollingpolicies.OnCheckpointRollingPolicy;
import org.apache.flink.streaming.connectors.elasticsearch7.ElasticsearchSinkFunction;
import org.apache.flink.streaming.connectors.elasticsearch7.RequestIndexer;
import org.apache.flink.streaming.connectors.elasticsearch7.common.ElasticsearchSinkConfig;
import org.apache.flink.streaming.connectors.elasticsearch7.common.ElasticsearchSinkFunction;
import org.apache.flink.streaming.connectors.elasticsearch7.common.ElasticsearchSinkRequest;
import org.apache.flink.streaming.connectors.elasticsearch7.common.ElasticsearchSinkRequest;
import org.apache.flink.streaming.connectors.elasticsearch7.common.ElasticsearchSinkRequest;
import org.apache.flink.streaming.connectors.elasticsearch7.common.ElasticsearchSinkRequest;
import org.elasticsearch.client.Requests;
import org.elasticsearch.common.xcontent.XContentType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class ElasticsearchWriter {
    public static void main(String[] args) throws Exception {
        List<HttpHost> httpHosts = new ArrayList<>();
        httpHosts.add(new HttpHost("localhost", 9200, "http"));

        ElasticsearchSink.Builder<String> esSinkBuilder = new ElasticsearchSink.Builder<>(
                httpHosts,
                (ElasticsearchSinkFunction<String>) (element, ctx, indexer) -> {
                    // 将数据写入Elasticsearch
                }
        );

        esSinkBuilder.setBulkFlushMaxActions(1);

        // 创建ElasticsearchSink
        ElasticsearchSink<String> sink