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();
     }

 }