Read.java
public class Read {
public static void main(String[] args) {
String conn = "db_url";
String username = "*****";
String pwd = "*****";
String sql = "INSERT INTO table (coloumn) values (?)";
Properties props = new Properties();
props.put("bootstrap.servers", "10.247.36.174:3306");
props.put("acks", "all");
props.put("retries", 0);
props.put("batch.size", 16384);
props.put("linger.ms", 1);
props.put("buffer.memory", 33554432);
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
Producer<String, String> producer = null;
try (Connection con = DriverManager.getConnection(conn, username, pwd);
PreparedStatement ps = con.prepareStatement(sql);
BufferedReader br = new BufferedReader(new FileReader("All.log"));) {
String line = null;
processMessages(line, br, listparam, ps);
break;
}
} catch (Exception ex) {
System.err.println("Error in \n" + ex);
} finally {
producer = new KafkaProducer<>(props);
String msg = "Done";
producer.send(new ProducerRecord<String, String>("HelloKafka", msg));
System.out.println("Sent: " + msg);
}
producer.close();
}
public static void processMessages(String line, BufferedReader br, List<String> list param, PreparedStatement ps)
throws Exception {
StringBuilder message = new StringBuilder();
message.append(line);
while ((line = br.readLine()) != null) {
String firstWord = line.split(" ", 2)[0];
if (listparam.contains(firstWord)) {
ps.setString(1, message.toString());
ps.executeUpdate();
message.setLength(0);
message.append(line);
} else {
message.append("\n" + line);
}
}
if (message.length() > 0) {
ps.setString(1, message.toString());
ps.executeUpdate();
}
}
}
Retrieve.java
public class Retrieve {
public static void main(String[] args) {
String conn = "db_url";
String username = "****";
String pwd = "****";
String sql = "SELECT * from table1";
Properties props = new Properties();
props.put("bootstrap.servers", "ipaddress");
props.put("group.id", "group-1");
props.put("enable.auto.commit", "true");
props.put("auto.commit.interval.ms", "1000");
props.put("auto.offset.reset", "earliest");
props.put("session.timeout.ms", "30000");
props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
props.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
KafkaConsumer<String, String> kafkaConsumer = new KafkaConsumer<>(props);
kafkaConsumer.subscribe(Arrays.asList("HelloKafka"));
while (true) {
ConsumerRecords<String, String> records = kafkaConsumer.poll(100);
for (ConsumerRecord<String, String> record : records) {
if (record.value().equals("Done")) {
try (Connection con = ...;
PreparedStatement ps = ....;) {
ResultSet rs =.....;
while (rs.next()) {
String rawData = rs.getString("RawData");
}
} catch (Exception ex) {
System.err.println("Error in \n" + ex);
}
}
}
}
}
}
我是Kafka的新手。谁能告诉我我错了哪一部分？我不知道如何在Java中使用Kafka。在ReadLg.java中，我想从日志文件中读取并将其插入DB中，然后在完成后想向RetrieveData.java发送一条消息，以便它可以启动。检索数据将运行，但是空闲状态等待来自ReadLg.java的消息。这是一个不好的方法吗？还是旧方法？任何建议或帮助解决此问题？我不断收到错误消息，无法连接到IP地址
下面是错误消息：
14:23:00.482 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Node -1 disconnected.
14:23:00.482 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:00.532 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:00.583 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:00.633 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:00.683 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:00.733 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:00.784 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:00.834 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:00.885 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:00.935 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:00.985 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:01.036 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:01.086 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:01.137 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:01.187 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:01.238 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:01.289 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:01.339 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:01.389 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:01.439 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Give up sending metadata request since no node is available
14:23:01.490 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Initialize connection to node 10.247.36.174:3306 (id: -1 rack: null) for sending metadata request
14:23:01.490 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Initiating connection to node 10.247.36.174:3306 (id: -1 rack: null)
14:23:02.012 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.common.network.Selector - [Producer clientId=producer-1] Created socket with SO_RCVBUF = 32768, SO_SNDBUF = 131072, SO_TIMEOUT = 0 to node -1
14:23:02.012 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Completed connection to node -1. Fetching API versions.
14:23:02.012 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=producer-1] Initiating API versions fetch from node -1.
14:23:02.520 [kafka-producer-network-thread | producer-1] DEBUG org.apache.kafka.common.network.Selector - [Producer clientId=producer-1] Connection with /10.247.36.174 disconnected
java.io.EOFException: null
答案 0 :(得分：1)
总结：首先要使用Kafka Consumer / Producer，您必须启动Zookeeper和Kafka经纪人。
出于测试或开发目的，您可以使用以下命令自行启动：
如果您的Kafka准备就绪，则可以开始使用它。您必须为bootstrap.server设置适当的值（对于本地使用，通常为localhost:9092）