dts reader

package com.aliyun.dts.connect;

import com.alibaba.fastjson.JSONObject;
import com.aliyun.drc.client.message.DataMessage;
import com.aliyun.drc.clusterclient.ClusterClient;
import com.aliyun.drc.clusterclient.ClusterListener;
import com.aliyun.drc.clusterclient.DefaultClusterClient;
import com.aliyun.drc.clusterclient.RegionContext;
import com.aliyun.drc.clusterclient.message.ClusterMessage;

import java.io.UnsupportedEncodingException;
import java.util.List;

public class DTSReader {

    private final ClusterClient dts_client;

    public DTSReader(String accessKey, String accessSecret, String subscribeInstanceID) throws  Exception {
        this.dts_client = initClusterClient(accessKey, accessSecret, subscribeInstanceID);
    }


    private ClusterClient initClusterClient(String accessKey, String accessSecret, String subscribeInstanceID)
            throws Exception {
        // 创建一个context,仅是属性设置
        RegionContext context = new RegionContext();
        // 运行SDK的服务器是否使用公网IP连接DTS(若使用内网IP访问，需要设置false)
        // 在订阅任务启动时，需要网络连接时需要关注该设置项
        context.setUsePublicIp(true);
        // 设置用户accessKey secret
        context.setAccessKey(accessKey);
        context.setSecret(accessSecret);

        // 创建消费者
        ClusterClient client = new DefaultClusterClient(context);
        ClusterListener listener = new ClusterListener() {
            // @Override
            public void noException(Exception e) {
                // TODO Auto-generated method stub
                e.printStackTrace();
            }



            // @Override
            public void notify(List<ClusterMessage> messages) throws Exception {
                //处理订阅任务收到的消息
                for (ClusterMessage message : messages) {
                    replicateMessage(message);
                }
            }
        };

        client.askForGUID(subscribeInstanceID);
        client.addConcurrentListener(listener);

        return client;
    }

    private void replicateMessage(final ClusterMessage message) {
        // 处理消息
        try {
            // 转换消息格式并处理
            convertRecord(message);
            // 确认消息以消费
            message.ackAsConsumed();
        } catch (Exception e) {
            // TODO 根据业务需求进行必要的重试
            e.printStackTrace();
        }
    }

    private void convertRecord(ClusterMessage message) throws UnsupportedEncodingException {
        DataMessage.Record record = message.getRecord();
        System.out.println("Record Op type:" + record.getOpt().toString());
        JSONObject jsonRecord;
        String key = null;
        switch (record.getOpt()) {
            case INSERT: // 数据插入
                jsonRecord = convertFields(record, 0, 1);
                key = record.getPrimaryKeys();
                System.out.println("Record Insert:Json format:" + jsonRecord.toJSONString());
                break;
            case UPDATE:// 数据更新
            case REPLACE:// replace操作
                JSONObject oldJsonRecord = convertFields(record, 0, 2);
                System.out.println("Record Update Before:Json format:" + oldJsonRecord.toJSONString());
                jsonRecord = convertFields(record, 1, 2);
                System.out.println("Record Update Before:Json format:" + jsonRecord.toJSONString());
                key = record.getPrimaryKeys();
                break;
            case DELETE:// 数据删除
                jsonRecord = convertFields(record, 0, 1);
                System.out.println("Record Delete:Json format:" + jsonRecord.toJSONString());
                key = record.getPrimaryKeys();
                break;
            default:
                return;
        }
        //数据表中对主Key列名
        System.out.println("PrimaryKey Column Name:" + key);
        //drds中物理数据库名和物理数据表名
        System.out.println("Record DB Name:"+record.getDbname()+",Table Name:"+record.getTablename());
        //drds中逻辑数据库名和逻辑表名
        System.out.println("Record Logical DB Name:"+record.getLogicalDbname()+",Table Name:"+record.getLogicalTablename());

    }

    // 将消息组成JSON格式输出
    private JSONObject convertFields(DataMessage.Record record, int start, int step)
            throws UnsupportedEncodingException {
        List<DataMessage.Record.Field> fields = record.getFieldList();
        JSONObject ret = new JSONObject();
        for (int i = start; i < fields.size(); i += step) {
            DataMessage.Record.Field field = fields.get(i);
            JSONObject object = new JSONObject();
            object.put("type", field.getType().toString());
            object.put("encoding", field.getEncoding());
            if (field.getValue() != null) {
                object.put("value", field.getValue().toString(field.getEncoding()));
            } else {
                object.put("value", null);
            }
            ret.put(field.getFieldname(), object);
        }
        return ret;
    }

    public void start() throws Exception {
        System.out.println("Start DTS subscription client...");
        dts_client.start();
    }

    public void stop() throws Exception {
        System.out.println("Stop DTS Subscription Client...");
        dts_client.stop();
    }


}