flink 通过事务和checkpoint的共同提交，保证EXACTLY

获得gp的数据库连接池，使用连接池，不要使用单连接

package com.ysservice.dataStreamApi.utils;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

public class DruidConnectionPool {

    private transient static DataSource dataSource = null;
    private transient static Properties props = new Properties();

    // 静态代码块
    static {
        props.put("driverClassName", "org.postgresql.Driver");
        props.put("url", SystemConstants.dataOutput_url_greenPlum_dwh);
        props.put("username", SystemConstants.dataOutput_username_greenPlum_dwh);
        props.put("password", SystemConstants.dataOutput_password_greenPlum_dwh);
        try {
            dataSource = DruidDataSourceFactory.createDataSource(props);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private DruidConnectionPool() {
    }

    public static Connection getConnection() throws SQLException {
        return dataSource.getConnection();
    }
}

GreenPlumTwoPhaseCommitSink，使用两阶段提交，保证checkpoint和数据写入一同成功

package com.ysservice.dataStreamApi.sink;

import com.ysservice.dataStreamApi.utils.DruidConnectionPool;
import org.apache.flink.api.common.ExecutionConfig;
import org.apache.flink.api.common.typeutils.base.VoidSerializer;
import org.apache.flink.api.java.typeutils.runtime.kryo.KryoSerializer;
import org.apache.flink.streaming.api.functions.sink.TwoPhaseCommitSinkFunction;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;


public class GreenPlumTwoPhaseCommitSink extends TwoPhaseCommitSinkFunction {

    // 定义可用的构造函数
    public GreenPlumTwoPhaseCommitSink() {
        super(new KryoSerializer<>(GreenPlumTwoPhaseCommitSink.ConnectionState.class, new ExecutionConfig()),
                VoidSerializer.INSTANCE);
    }


    @Override
    protected ConnectionState beginTransaction() throws Exception {
        //使用连接池，不使用单个连接
        Connection connection = DruidConnectionPool.getConnection();
        connection.setAutoCommit(false);//设定不自动提交
        return new ConnectionState(connection);
    }


    @Override
    protected void invoke(ConnectionState transaction, String value, Context context) throws Exception {

        Connection connection = transaction.connection;
        String sql = value.split("<-tableNameSplitPoint->")[1];
        PreparedStatement pstm = connection.prepareStatement(sql);
        int i = 0;
        try {
            i = pstm.executeUpdate();
        } catch (SQLException throwables) {
            PreparedStatement pstm2 = connection.prepareStatement("insert into cdc_log.cdc_error_sql(error_sql) values ('错误sql:" + sql + "')");
            i = pstm2.executeUpdate();
            pstm2.close();
        }
        if (i == 0) {
            PreparedStatement pstm3 = connection.prepareStatement("insert into cdc_log.cdc_error_sql(error_sql) values ('执行后未更新数据库的sql:" + sql + "')");
            pstm3.executeUpdate();
            pstm3.close();
        }
        pstm.close();
    }


    // 先不做处理
    @Override
    protected void preCommit(ConnectionState transaction) throws Exception {
    }

    //提交事务
    @Override
    protected void commit(ConnectionState transaction) {
        Connection connection = transaction.connection;
        try {
            connection.commit();
            connection.close();
        } catch (SQLException e) {
            throw new RuntimeException("提交事物异常");
        }
    }

    //回滚事务
    @Override
    protected void abort(ConnectionState transaction) {
        System.out.println("=====> abort... ");
        Connection connection = transaction.connection;
        try {
            connection.rollback();
            connection.close();
        } catch (SQLException e) {
            throw new RuntimeException("回滚事物异常");
        }
    }

    //定义建立数据库连接的方法
    public static class ConnectionState {
        private final transient Connection connection;
        public ConnectionState(Connection connection) {
            this.connection = connection;
        }
    }
}