使用Apache Flink实现实时数据同步与清洗:MySQL和Oracle到目标MySQL的ETL流程

实现数据同步的ETL(抽取、转换、加载)过程通常涉及从源系统(如数据库、消息队列或文件)中抽取数据,进行必要的转换,然后将数据加载到目标系统(如另一个数据库或数据仓库)。在这里,我们将展示如何使用Apache Flink来实现一个从MySQL或Oracle数据库抽取数据并同步到另一个MySQL数据库的ETL过程。

  • 1. 从源数据库(MySQL和Oracle)实时抽取数据
  • 2. 对数据进行清洗和转换
  • 3. 将转换后的数据写入目标数据库(MySQL)
    请添加图片描述

我们将使用Apache Flink来实现这个流程。Flink具有强大的数据流处理能力,适合处理实时数据同步和转换任务。

环境准备

  • 确保MySQL和Oracle数据库运行**,并创建相应的表。
  • 创建Spring Boot项目,并添加Flink、MySQL JDBC、和Oracle JDBC驱动的依赖。

第一步:创建源和目标数据库表

假设我们有以下三个表:

  • source_mysql_table(MySQL中的源表)
  • source_oracle_table(Oracle中的源表)
  • target_table(目标MySQL表)

MySQL源表

CREATE DATABASE source_mysql_db;
USE source_mysql_db;

CREATE TABLE source_mysql_table (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id VARCHAR(255) NOT NULL,
    action VARCHAR(255) NOT NULL,
    timestamp VARCHAR(255) NOT NULL
);

Oracle源表

CREATE TABLE source_oracle_table (
    id NUMBER GENERATED BY DEFAULT ON NULL AS IDENTITY,
    user_id VARCHAR2(255) NOT NULL,
    action VARCHAR2(255) NOT NULL,
    timestamp VARCHAR2(255) NOT NULL,
    PRIMARY KEY (id)
);

目标MySQL表

CREATE DATABASE target_db;
USE target_db;

CREATE TABLE target_table (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id VARCHAR(255) NOT NULL,
    action VARCHAR(255) NOT NULL,
    timestamp VARCHAR(255) NOT NULL
);

第二步:添加项目依赖

在pom.xml中添加Flink、MySQL和Oracle相关的依赖:

<dependencies>
    <!-- Spring Boot dependencies -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>

    <!-- Apache Flink dependencies -->
    <dependency>
        <groupId>org.apache.flink</groupId>
        <artifactId>flink-streaming-java_2.12</artifactId>
        <version>1.14.0</version>
    </dependency>
    <dependency>
        <groupId>org.apache.flink</groupId>
        <artifactId>flink-clients_2.12</artifactId>
        <version>1.14.0</version>
    </dependency>

    <!-- MySQL JDBC driver -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.23</version>
    </dependency>

    <!-- Oracle JDBC driver -->
    <dependency>
        <groupId>com.oracle.database.jdbc</groupId>
        <artifactId>ojdbc8</artifactId>
        <version>19.8.0.0</version>
    </dependency>
</dependencies>

第三步:编写Flink ETL任务

创建一个Flink任务类来实现ETL逻辑。

创建一个POJO类表示数据结构

package com.example.flink;

public class UserAction {
    private int id;
    private String userId;
    private String action;
    private String timestamp;

    // Getters and setters
    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getUserId() {
        return userId;
    }

    public void setUserId(String userId) {
        this.userId = userId;
    }

    public String getAction() {
        return action;
    }

    public void setAction(String action) {
        this.action = action;
    }

    public String getTimestamp() {
        return timestamp;
    }

    public void setTimestamp(String timestamp) {
        this.timestamp = timestamp;
    }
}

编写Flink任务类

package com.example.flink;

import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.api.common.functions.RichFlatMapFunction;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.source.SourceFunction;
import org.apache.flink.util.Collector;
import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;

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

@Component
public class FlinkETLJob implements CommandLineRunner {

    @Override
    public void run(String... args) throws Exception {
        final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        // 从MySQL读取数据
        DataStream<UserAction> mysqlDataStream = env.addSource(new MySQLSource());

        // 从Oracle读取数据
        DataStream<UserAction> oracleDataStream = env.addSource(new OracleSource());

        // 合并两个数据流
        DataStream<UserAction> mergedStream = mysqlDataStream.union(oracleDataStream);

        // 清洗和转换数据
        DataStream<UserAction> transformedStream = mergedStream.map(new MapFunction<UserAction, UserAction>() {
            @Override
            public UserAction map(UserAction value) throws Exception {
                // 进行清洗和转换
                value.setAction(value.getAction().toUpperCase());
                return value;
            }
        });

        // 将数据写入目标MySQL数据库
        transformedStream.addSink(new MySQLSink());

        // 执行任务
        env.execute("Flink ETL Job");
    }

    public static class MySQLSource implements SourceFunction<UserAction> {
        private static final String JDBC_URL = "jdbc:mysql://localhost:3306/source_mysql_db";
        private static final String JDBC_USER = "source_user";
        private static final String JDBC_PASSWORD = "source_password";
        private volatile boolean isRunning = true;

        @Override
        public void run(SourceContext<UserAction> ctx) throws Exception {
            try (Connection connection = DriverManager.getConnection(JDBC_URL, JDBC_USER, JDBC_PASSWORD)) {
                while (isRunning) {
                    String sql = "SELECT * FROM source_mysql_table";
                    try (PreparedStatement statement = connection.prepareStatement(sql);
                         ResultSet resultSet = statement.executeQuery()) {
                        while (resultSet.next()) {
                            UserAction userAction = new UserAction();
                            userAction.setId(resultSet.getInt("id"));
                            userAction.setUserId(resultSet.getString("user_id"));
                            userAction.setAction(resultSet.getString("action"));
                            userAction.setTimestamp(resultSet.getString("timestamp"));
                            ctx.collect(userAction);
                        }
                    }
                    Thread.sleep(5000); // 模拟实时数据流,每5秒查询一次
                }
            }
        }

        @Override
        public void cancel() {
            isRunning = false;
        }
    }

    public static class OracleSource implements SourceFunction<UserAction> {
        private static final String JDBC_URL = "jdbc:oracle:thin:@localhost:1521:orcl";
        private static final String JDBC_USER = "source_user";
        private static final String JDBC_PASSWORD = "source_password";
        private volatile boolean isRunning = true;

        @Override
        public void run(SourceContext<UserAction> ctx) throws Exception {
            try (Connection connection = DriverManager.getConnection(JDBC_URL, JDBC_USER, JDBC_PASSWORD)) {
                while (isRunning) {
                    String sql = "SELECT * FROM source_oracle_table";
                    try (PreparedStatement statement = connection.prepareStatement(sql);
                         ResultSet resultSet = statement.executeQuery()) {
                        while (resultSet.next()) {
                            UserAction userAction = new UserAction();
                            userAction.setId(resultSet.getInt("id"));
                            userAction.setUserId(resultSet.getString("user_id"));
                            userAction.setAction(resultSet.getString("action"));
                            userAction.setTimestamp(resultSet.getString("timestamp"));
                            ctx.collect(userAction);
                        }
                    }
                    Thread.sleep(5000); // 模拟实时数据流,每5秒查询一次
                }
            }
        }

        @Override
        public void cancel() {
            isRunning = false;
        }
    }

    public static class MySQLSink extends RichFlatMapFunction<UserAction, Void> {
        private static final String JDBC_URL = "jdbc:mysql://localhost:3306/target_db";
        private static final String JDBC_USER = "target_user";
        private static final String JDBC_PASSWORD = "target_password";
        private transient Connection connection;
        private transient PreparedStatement statement;

        @Override
        public void open(Configuration parameters) throws Exception {
            super.open(parameters);
            connection = DriverManager.getConnection(JDBC_URL, JDBC_USER, JDBC_PASSWORD);
            String sql = "INSERT INTO target_table (user_id, action, timestamp) VALUES (?, ?, ?)";
            statement = connection.prepareStatement(sql);
        }

        @Override
        public void flatMap(UserAction value, Collector<Void> out) throws Exception {
            statement.setString(1, value.getUserId());
            statement.setString(2, value.getAction());
            statement.setString(3, value.getTimestamp());
            statement.executeUpdate();
        }

        @Override
        public void close() throws Exception {
            super.close();
            if (statement != null) {
                statement.close();
            }
            if (connection != null) {
                connection.close();
            }
        }
    }
}

第四步:配置Spring Boot

在application.properties中添加必要的配置:

# Spring Boot configuration
server.port=8080

第五步:运行和测试

  • 启动MySQL和Oracle数据库:确保你的源和目标数据库已经运行,并且创建了相应的数据库和表。
  • 启动Spring Boot应用:启动Spring Boot应用程序,会自动运行Flink ETL任务。
  • 测试Flink ETL任务:插入一些数据到源数据库的表中,验证数据是否同步到目标数据库的表中。

总结

通过上述步骤,你可以在Spring Boot项目中集成Flink并实现实时数据同步和ETL流程。这个示例展示了如何从MySQL和Oracle源数据库实时抽取数据,进行数据清洗和转换,并将结果加载到目标MySQL数据库中。根据你的具体需求,你可以扩展和修改这个示例,处理更复杂的数据转换和加载逻辑。

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