Kafka环境搭建
- 下载地址：https://link.zhihu.com/?target=https%3A//kafka.apache.org/downloads
- 解压
- 启动zookeeper
bin/zookeeper-server-start.sh config/zookeeper.properties
需要注意的是 : " c o n f i g / z o o k e e p e r . p r o p e r t i e s " 目录和 " / c o n f i g / z o o k e e p e r . p r o p e r t i e s " 目录是不同的 . 前者指当前目录中 c o n f i g 目录下的 z o o k e e p e r . p r o p e r t i e s 文件， 后者代表根目录中 c o n f i g 目录下的 z o o k e e p e r . p r o p e r t i e s 文件。 \color{red}需要注意的是:\\ "config/zookeeper.properties"目录和 "/config/zookeeper.properties"目录是不同的.\\ 前者指当前目录中config目录下的zookeeper.properties文件，\\ 后者代表根目录中config目录下的zookeeper.properties文件。 需要注意的是:"config/zookeeper.properties"目录和"/config/zookeeper.properties"目录是不同的.前者指当前目录中config目录下的zookeeper.properties文件，后者代表根目录中config目录下的zookeeper.properties文件。
若启动不成功，需要将zookeeper.properties中的admin.EnableServer=false修改为admin.EnableServer=true
或者关闭zookeeper并重新启动：
bin/zookeeper-server-stop.sh
- 启动kafka
bin/kafka-server-start.sh config/server.properties
- 创建topic
kafka-topics.sh --create --zookeeper cluster1:9092,cluster2: 9092,cluster3: 9092--replication-factor 3 --partitions 1 --topic ljg
若发生错误：”zookeeper is not a recognized option”则将参数换成“—BOOTSTRAP-SERVER”，即：
./bin/kafka-topics.sh --create --bootstrap-server localhost:9092 --replication-factor 1 --partitions 1 --topic ljg
上述两者的区别是，–zookeeper 和cluster都是老版本的命令参数，新版本可能不再支持。
- 创建生产者
kafka-console-producer.sh --broker-list cluster1:9092 --topic ljg
或者：
./bin/kafka-console-producer.sh --bootstrap-server localhost:9092 --topic ljg
上述两者的区别是，–broker-list 和cluster都是老版本的命令参数，新版本可能不再支持。
- 创建消费者
./bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic ljg
此时生产者即可进入等待输入，并将消息发送给消费者。
2181端口用于管理Kafka集群的元数据信息，包括Kafka的配置信息、分区信息、消费者信息等。而9092端口是Kafka Broker的默认端口，用于接收和处理生产者和消费者的消息，以及进行数据的存储和传输。
参考链接：https://www.cnblogs.com/anquing/p/14523046.html
maven下载安装、设置
- 下载解压
- 设置工作目录
- 设置镜像
- 编译java项目
mave命令：
mvn clean：清理
mvn compile：编译主程序
mvn test-compile：编译测试程序
mvn test：执行测试
mvn package：打包
mvn install：安装
maven项目目录结构：
Hello.java内容：
package com.maven.test;
public class hello {
public String sayHello(String name){
return "Hello "+name+"!";
}
}
注意pom.xml中的name 和artifactId字段的区别。
pom.xml例子：
<?xml version="1.0" ?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.maven.test</groupId>
<artifactId>hello</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>hello</name>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.0</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>
数据库安装和操作
安装mabiadb数据库
yum install mariadb-server
systemctl start mariadb
systemctl enable mariadb
mysql_secure_installation
创建数据表：
mysql -uroot -p
create database kafkaTestDB;
use kafkaTestDB;
create table kafkaTestTable(tickcount varchar(64), value varchar(64),time varchar(64));
java连接和操作数据库：
package Main;
import java.sql.*;
public class JDBC {
public static void main(String[] args) throws SQLException, ClassNotFoundException {
// 1.加载驱动
Class.forName("com.mysql.cj.jdbc.Driver");
// 2.用户信息和url
String url = "jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8&useSSL=true";
String username="root";
String password="root";
// 3.连接成功，数据库对象 Connection
Connection connection = DriverManager.getConnection(url,username,password);
// 4.执行SQL对象Statement，执行SQL的对象
Statement statement = connection.createStatement();
// 5.执行SQL的对象去执行SQL，返回结果集
String sql = "SELECT *FROM studentinfo;";
ResultSet resultSet = statement.executeQuery(sql);
while(resultSet.next()){
System.out.println("SNo="+resultSet.getString("SNo"));
System.out.println("SName="+resultSet.getString("SName"));
System.out.println("Birth="+resultSet.getString("Birth"));
System.out.println("SPNo="+resultSet.getString("SPNo"));
System.out.println("Major="+resultSet.getString("Major"));
System.out.println("Grade="+resultSet.getString("Grade"));
System.out.println("SInstructor="+resultSet.getString("SInstructor"));
System.out.println("SPwd="+resultSet.getString("SPwd"));
}
// 6.释放连接
resultSet.close();
statement.close();
connection.close();
}
}
JAVA代码（maven）构建生产者消费者
工程目录：
pom.xml:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.bjtu.kafkaTest</groupId>
<artifactId>kafkaTest</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.apache.kafka</groupId>
<artifactId>kafka-clients</artifactId>
<version>2.2.1</version>
</dependency>
<dependency>
<groupId>org.apache.kafka</groupId>
<artifactId>kafka-streams</artifactId>
<version>2.2.1</version>
</dependency>
<dependency>
<groupId> org.apache.cassandra</groupId>
<artifactId>cassandra-all</artifactId>
<version>0.8.1</version>
<exclusions>
<exclusion>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
</exclusion>
<exclusion>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.26</version>
</dependency>
<dependency>
<groupId>joda-time</groupId>
<artifactId>joda-time</artifactId>
<version>2.9.8</version>
</dependency>
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20180130</version>
</dependency>
</dependencies>
</project>
java源码：
consumer：
package com.bjtu.kafkaTest;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import java.util.Arrays;
import java.sql.*;
import java.util.Properties;
import org.json.*;
public class ConsumerDemo {
public static void mysqlAccess(String tick,String value,String t) {
try{
Class.forName("com.mysql.cj.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/";
String username="root";
String password="1234";
Connection connection = DriverManager.getConnection(url,username,password);
Statement statement = connection.createStatement();
String sql = "use kafkaTestDB;";
ResultSet resultSet = statement.executeQuery(sql);
//sql = "SELECT *FROM kafkaTestTable;";
//resultSet = statement.executeQuery(sql);
//while(resultSet.next()){
// System.out.println("tickcount:"+resultSet.getString("tickcount"));
//}
sql = "insert into kafkaTestTable values(" + tick +"," + value + "," + t + ")";
resultSet = statement.executeQuery(sql);
System.out.println(sql);
resultSet.close();
statement.close();
connection.close();
}
catch(Exception e){
System.out.println(e.toString());
}
}
public static void main(String[] args){
System.out.println("consumer start\r\n");
Statement statement = null;
Connection connection = null;
ResultSet resultSet = null;
try{
Class.forName("com.mysql.cj.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/";
String username="root";
String password="1234";
connection = DriverManager.getConnection(url,username,password);
statement = connection.createStatement();
String sql = "use kafkaTestDB;";
resultSet = statement.executeQuery(sql);
//sql = "SELECT *FROM kafkaTestTable;";
//resultSet = statement.executeQuery(sql);
//while(resultSet.next()){
// System.out.println("tickcount:"+resultSet.getString("tickcount"));
//}
}
catch(Exception e){
System.out.println(e.toString());
return;
}
Properties properties = new Properties();
properties.put("bootstrap.servers", "0.0.0.0:9092");
properties.put("group.id", "zabbix_perf");
properties.put("enable.auto.commit", "true");
properties.put("auto.commit.interval.ms", "1000");
/**
* earliest
* 当各分区下有已提交的offset时，从提交的offset开始消费；无提交的offset时，从头开始消费
* latest
* 当各分区下有已提交的offset时，从提交的offset开始消费；无提交的offset时，消费新产生的该分区下的数据
* none
* topic各分区都存在已提交的offset时，从offset后开始消费；只要有一个分区不存在已提交的offset，则抛出异常
*
*/
properties.put("auto.offset.reset", "earliest");
properties.put("session.timeout.ms", "30000");
/**
* 反序列化
* 把kafka集群二进制消息反序列化指定类型。
*/
properties.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
properties.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
KafkaConsumer<String, String> kafkaConsumer = new KafkaConsumer<>(properties);
kafkaConsumer.subscribe(Arrays.asList("ljg"));
while (true) {
ConsumerRecords<String, String> records = kafkaConsumer.poll(100);//100是超时时间
for (ConsumerRecord<String, String> record : records) {
System.out.printf("offset = %d, value = %s", record.offset(), record.value());
JSONObject jo = new JSONObject(record.value());
try{
String tick = jo.getString("tickcount");
String value = jo.getString("value");
String t = jo.getString("time");
//mysqlAccess(tick,value,t);
//System.out.println("tick:"+tick + ",value:"+value + ",time:"+t);
String sql = "insert into kafkaTestTable values(\"" +
tick + "\",\"" + value + "\",\"" + t + "\")";
System.out.println(sql);
int result = statement.executeUpdate(sql);
}catch(Exception e){
System.out.println(e.toString());
break;
}
}
}
//try{
//resultSet.close();
//statement.close();
//connection.close();
//}catch(Exception e){
// System.out.println(e.toString());
//}
}
}
producer:
package com.bjtu.kafkaTest;
import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.Producer;
import org.apache.kafka.clients.producer.ProducerRecord;
import java.util.Properties;
import java.util.Random;
import java.util.Date;
import java.time.LocalDate;
import org.joda.time.DateTime;
import java.text.SimpleDateFormat;
public class ProducerDemo {
public static void main(String[] args){
System.out.println("producer start\r\n");
Properties properties = new Properties();
/**
*bootstrap.server用于建立到Kafka集群的初始连接的主机/端口对的列表，如果有两台以上的机器，逗号分隔
*/
properties.put("bootstrap.servers", "0.0.0.0:9092");
/**
* acks有三种状态
* acks=0 不等待服务器确认直接发送消息，无法保证服务器收到消息数据
* acks=1 把消息记录写到本地，但不会保证所有的消息数据被确认记录的情况下进行释放
* acks=all 确认所有的消息数据被同步副本确认，这样保证了记录不会丢失
*
*/
properties.put("acks", "all");
/**
* 设置成大于0将导致客户端重新发送任何发送失败的记录
*
*/
properties.put("retries", 0);
/**
*16384字节是默认设置的批处理的缓冲区
*/
properties.put("batch.size", 16384);
properties.put("linger.ms", 1);
properties.put("buffer.memory", 33554432);
/**
* 序列化类型。
* kafka是以键值对的形式发送到kafka集群的，key是可选的，value可以是任意类型，Message再被发送到kafka之前，Producer需要
* 把不同类型的消息转化成二进制类型。
*/
properties.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
properties.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
Producer<String, String> producer = null;
try {
producer = new KafkaProducer<String, String>(properties);
Random r = new Random();
for (int i = 0; i < 1000; i++) {
int rv = r.nextInt(0x10000000);
long timestamp = System.currentTimeMillis();
Date date = new Date(timestamp + rv);
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss");
String formattedDate = sdf.format(date);
//System.out.println("格式化后的日期：" + formattedDate);
String msg = "{\"tickcount\":\"" + formattedDate + "\",\"value\":\"" +formattedDate +"\",\"time\":\"" + formattedDate + "\"}" ;
producer.send(new ProducerRecord<String, String>("ljg", msg));
System.out.println("Sent:" + msg);
//Thread.sleep(1);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
producer.close();
}
System.out.println("producer end\r\n");
}
}
安装依赖包：
mvn idea:module
编译运行：
执行：
mvn exec:java -Dexec.mainClass="com.bjtu.kafkaTest.ConsumerDemo"
mvn exec:java -Dexec.mainClass="com.bjtu.kafkaTest.ProducerDemo"
参考链接：
https://www.cnblogs.com/qqran/p/14772713.html
