fixed issue #2067 , add example

example/src/main/java/com/alibaba/otter/canal/example/kafka/CanalKafkaClientFlatMessageExample.java

@@ -0,0 +1,146 @@
+package com.alibaba.otter.canal.example.kafka;
+
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.util.Assert;
+
+import com.alibaba.otter.canal.client.kafka.KafkaCanalConnector;
+import com.alibaba.otter.canal.protocol.FlatMessage;
+
+/**
+ * Kafka client example
+ *
+ * @author machengyuan @ 2018-6-12
+ * @version 1.0.0
+ */
+public class CanalKafkaClientFlatMessageExample {
+
+    protected final static Logger           logger  = LoggerFactory.getLogger(CanalKafkaClientFlatMessageExample.class);
+
+    private KafkaCanalConnector             connector;
+
+    private static volatile boolean         running = false;
+
+    private Thread                          thread  = null;
+
+    private Thread.UncaughtExceptionHandler handler = new Thread.UncaughtExceptionHandler() {
+
+                                                        public void uncaughtException(Thread t, Throwable e) {
+                                                            logger.error("parse events has an error", e);
+                                                        }
+                                                    };
+
+    public CanalKafkaClientFlatMessageExample(String zkServers, String servers, String topic, Integer partition,
+                                              String groupId){
+        connector = new KafkaCanalConnector(servers, topic, partition, groupId, null, true);
+    }
+
+    public static void main(String[] args) {
+        try {
+            final CanalKafkaClientFlatMessageExample kafkaCanalClientExample = new CanalKafkaClientFlatMessageExample(AbstractKafkaTest.zkServers,
+                AbstractKafkaTest.servers,
+                AbstractKafkaTest.topic,
+                AbstractKafkaTest.partition,
+                AbstractKafkaTest.groupId);
+            logger.info("## start the kafka consumer: {}-{}", AbstractKafkaTest.topic, AbstractKafkaTest.groupId);
+            kafkaCanalClientExample.start();
+            logger.info("## the canal kafka consumer is running now ......");
+            Runtime.getRuntime().addShutdownHook(new Thread() {
+
+                public void run() {
+                    try {
+                        logger.info("## stop the kafka consumer");
+                        kafkaCanalClientExample.stop();
+                    } catch (Throwable e) {
+                        logger.warn("##something goes wrong when stopping kafka consumer:", e);
+                    } finally {
+                        logger.info("## kafka consumer is down.");
+                    }
+                }
+
+            });
+            while (running)
+                ;
+        } catch (Throwable e) {
+            logger.error("## Something goes wrong when starting up the kafka consumer:", e);
+            System.exit(0);
+        }
+    }
+
+    public void start() {
+        Assert.notNull(connector, "connector is null");
+        thread = new Thread(new Runnable() {
+
+            public void run() {
+                process();
+            }
+        });
+        thread.setUncaughtExceptionHandler(handler);
+        thread.start();
+        running = true;
+    }
+
+    public void stop() {
+        if (!running) {
+            return;
+        }
+        running = false;
+        if (thread != null) {
+            try {
+                thread.join();
+            } catch (InterruptedException e) {
+                // ignore
+            }
+        }
+    }
+
+    private void process() {
+        while (!running) {
+            try {
+                Thread.sleep(1000);
+            } catch (InterruptedException e) {
+            }
+        }
+
+        while (running) {
+            try {
+                connector.connect();
+                connector.subscribe();
+                while (running) {
+                    try {
+                        List<FlatMessage> messages = connector.getFlatList(100L, TimeUnit.MILLISECONDS); // 获取message
+                        if (messages == null) {
+                            continue;
+                        }
+                        for (FlatMessage message : messages) {
+                            long batchId = message.getId();
+                            int size = message.getData().size();
+                            if (batchId == -1 || size == 0) {
+                                // try {
+                                // Thread.sleep(1000);
+                                // } catch (InterruptedException e) {
+                                // }
+                            } else {
+                                // printSummary(message, batchId, size);
+                                // printEntry(message.getEntries());
+                                logger.info(message.toString());
+                            }
+                        }
+
+                        connector.ack(); // 提交确认
+                    } catch (Exception e) {
+                        logger.error(e.getMessage(), e);
+                    }
+                }
+            } catch (Exception e) {
+                logger.error(e.getMessage(), e);
+            }
+        }
+
+        connector.unsubscribe();
+        connector.disconnect();
+    }
+}