目录
需求分析
RabbitMQ 客户端设定
ConnectionFactory(连接工厂)
Connection(连接)
Channel(通道)
针对 客户端 和 服务器 单元测试
需求分析
RabbitMQ 客户端设定
一个客户端可以有多个模块每个模块均可以和 Broker Server 之间建立 "逻辑上的连接"(channel)这几个模块的 channel 彼此之间是相互不影响的同时这几个 channel 复用了同一个 TCP 连接此处我们将仿照 RabbitMQ 客户端设定
ConnectionFactory(连接工厂)
这个类持有服务器的地址该类用于创建 Connection 对象
具体代码编写:
import lombok.Getter;
import lombok.Setter;
import java.io.IOException;
@Getter
@Setter
public class ConnectionFactory {
// broker server 的 ip 地址
private String host;
// broker server 的端口号
private int port;
public Connection newConnection() throws IOException {
Connection connection = new Connection(host,port);
return connection;
}
// 访问 broker server 的哪个虚拟主机
// 下列几个属性暂时先不搞了
// private String virtualHostName;
// private String username;
// private String password;
}
Connection(连接)
这个类表示一个 TCP 连接,持有 Socket 对象该类用于写入请求/读取响应,管理多个 Channel 对象
具体代码编写:
编写成员变量
private Socket socket = null;
// 需要管理多个 channel 使用一个 hash 表把若干个 channel 组织起来
private ConcurrentHashMap
private InputStream inputStream;
private OutputStream outputStream;
private DataOutputStream dataOutputStream;
private DataInputStream dataInputStream;
//用来处理 0xc 的回调,这里开销可能会很大,不希望把 扫描线程 阻塞住,因此使用 线程池 来处理
private ExecutorService callbackPool = null;
编写构造方法此处不仅需要初始化成员变量,还需创建一个扫描线程,不停的从 socket 中读取响应数据,并将读取到的响应交给 dispatchResponse 方法执行
public Connection(String host, int port) throws IOException {
socket = new Socket(host,port);
inputStream = socket.getInputStream();
outputStream = socket.getOutputStream();
dataInputStream = new DataInputStream(inputStream);
dataOutputStream = new DataOutputStream(outputStream);
callbackPool = Executors.newFixedThreadPool(4);
// 创建一个 扫描线程,由这个线程负责不停的从 socket 中取响应数据 把这个响应数据再交给对应的 channel 负责处理
Thread t = new Thread(() -> {
try {
while (!socket.isClosed()) {
Response response = readResponse();
dispatchResponse(response);
}
}catch (SocketException e) {
// 连接正常断开,此时这个异常直接忽略
System.out.println("[Connection] 连接正常断开!");
}catch (IOException | ClassNotFoundException | MqException e) {
System.out.println("[Connection] 连接异常断开!");
e.printStackTrace();
}
});
t.start();
}
编写 dispatchResponse 方法使用该方法来区分,当前响应是一个针对控制请求的响应,还是服务器推送过来的消息如果是服务器推送过来的消息,type = 0xc,也就需要执行回调,通过线程池来执行如果只是一个普通的响应,就将该结果放到 channel 的 哈希表中随后 channel 的 putReturns 方法会唤醒所有阻塞等待的线程,让这些线程从 哈希表中拿与自己 rid 相等的返回结果
// 使用这个方法来分别处理,当前的响应是一个针对控制请求的响应,还是服务器推送的消息
private void dispatchResponse(Response response) throws IOException, ClassNotFoundException, MqException {
if(response.getType() == 0xc) {
// 服务器推送来的消息数据
SubScribeReturns subScribeReturns = (SubScribeReturns) BinaryTool.fromBytes(response.getPayload());
// 根据 channelId 找到对应的 channel 对象
Channel channel = channelMap.get(subScribeReturns.getChannelId());
if(channel == null) {
throw new MqException("[Connection] 该消息对应的 channel 在客户端中不存在!channelId = " + channel.getChannelId());
}
// 执行该 channel 对象内部的回调
// 此处我们直接将回调方法交给线程池来执行,而不是用扫描线程来执行
callbackPool.submit(() -> {
try {
channel.getConsumer().handleDelivery(subScribeReturns.getConsumerTag(),subScribeReturns.getBasicProperties(),
subScribeReturns.getBody());
} catch (MqException | IOException e) {
e.printStackTrace();
}
});
}else {
// 当前响应是针对刚才控制请求的响应
BasicReturns basicReturns = (BasicReturns) BinaryTool.fromBytes(response.getPayload());
// 把这个结果放到对应的 channel 的 hash 表中
Channel channel = channelMap.get(basicReturns.getChannelId());
if(channel == null) {
throw new MqException("[Connection] 该消息对应的 channel 在客户端中不存在!channelId = " + channel.getChannelId());
}
channel.putReturns(basicReturns);
}
}
编写 发送请求 与 读取响应 的方法
// 发送请求
public void writeRequest(Request request) throws IOException {
dataOutputStream.writeInt(request.getType());
dataOutputStream.writeInt(request.getLength());
dataOutputStream.write(request.getPayload());
dataOutputStream.flush();
System.out.println("[Connection] 发送请求! type = " + request.getType() + ",length = " + request.getLength());
}
// 读取响应
public Response readResponse() throws IOException {
Response response = new Response();
response.setType(dataInputStream.readInt());
response.setLength(dataInputStream.readInt());
byte[] payload = new byte[response.getLength()];
int n = dataInputStream.read(payload);
if(n != payload.length) {
throw new IOException("读取的响应数据不完整!");
}
response.setPayload(payload);
System.out.println("[Connection] 收到响应! type = " + response.getType() + ",length = " + response.getLength());
return response;
}
编写创建 channel 的方法
注意:
我们的代码中使用了多次 UUID message 的 id,就是用 UUID 当时加了个 M- 前缀现在 channel 的 id 也是使用 UUID 此时加个 C- 前缀rid 也使用 UUID 来生成,加个前缀 R-
// 通过这个方法,在 Connection 中能够创建出一个 Channel
public Channel createChannel() throws IOException, InterruptedException {
String channelId = "C-" + UUID.randomUUID().toString();
Channel channel = new Channel(channelId,this);
// 把这个 channel 对象放到 Connection 管理 channel 的 哈希表 中
channelMap.put(channelId,channel);
// 同时也需要把 创建 channel 的这个消息也告诉服务器
boolean ok = channel.createChannel();
if(!ok) {
// 服务器这里创建失败了!!整个这次创建 channel 操作不顺利!
// 把刚才已经加入 hash 表的键值对,再删了
channelMap.remove(channelId);
return null;
}
return channel;
}
编写释放 Connection 相关资源的方法
public void close() {
// 关闭 Connection 释放上述资源
try {
callbackPool.shutdownNow();
channelMap.clear();
inputStream.close();
outputStream.close();
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
Channel(通道)
这个类表示一个逻辑上的连接 该类用于提供一系列的方法,去和服务器提供的核心 API 相对应 客户端提供的这些方法,其方法内部就是发送了一个特定的请求
具体代码编写:
编写成员变量 与 构造方法
private String channelId;
// 当前这个 channel 属于哪个连接的
private Connection connection;
// 用来存储后续客户端收到的服务器的响应
private ConcurrentHashMap
// 如果当前 Channel 订阅了某个队列,就需要在此处记录下对应回调是啥,当该队列的消息返回回来的时候,调用回调
// 此处约定一个 Channel 中只能有一个回调
private Consumer consumer = null;
public Channel(String channelId,Connection connection) {
this.channelId = channelId;
this.connection = connection;
}
实现 type = 0x1,即创建 channel构造请求发给服务器,随后阻塞等待,唤醒后从 basicReturnsMap 中尝试获取响应结果其余 type (0xc 除外,因为 0xc 只有响应没有请求)类型的请求与 0x1 大差不差,对着所需参数,构造即可
// 在这个方法中,和服务器进行交互,告知服务器,此处客户端创建了新的 channel 了
public Boolean createChannel() throws IOException, InterruptedException {
// 对于创建 Channel 来说,
BasicArguments basicArguments = new BasicArguments();
basicArguments.setChannelId(channelId);
basicArguments.setRid(generateRid());
byte[] payload = BinaryTool.toBytes(basicArguments);
Request request = new Request();
request.setType(0x1);
request.setLength(payload.length);
request.setPayload(payload);
// 构造出完整请求之后,就可以发送这个请求了
connection.writeRequest(request);
// 等待服务器的响应
BasicReturns basicReturns = waitResult(basicArguments.getRid());
return basicReturns.isOk();
}
private String generateRid() {
return "R-" + UUID.randomUUID().toString();
}
// 期望使用这个方法来阻塞等待服务器的响应
private BasicReturns waitResult(String rid) throws InterruptedException {
BasicReturns basicReturns = null;
while ((basicReturns = basicReturnsMap.get(rid)) == null) {
// 如果查询结果为 null,说明响应还没回来
// 此时就需要阻塞等待
synchronized (this) {
wait();
}
}
// 读取成功之后,还需要把这个消息从 哈希表中给删除掉
basicReturnsMap.remove(rid);
System.out.println("[Channel] 获取到服务器响应!rid = " + rid);
return basicReturns;
}
public void putReturns(BasicReturns basicReturns) {
basicReturnsMap.put(basicReturns.getRid(),basicReturns);
synchronized (this) {
// 当前也不知道有多少个线程在等待上述的这个响应
// 把所有的等待的线程都唤醒
notifyAll();
}
}
特别注意 type = 0xa ,即 订阅消息
其次值得注意的是 consumerTag 使用 channelId 来表示
// 订阅消息
public boolean basicConsume(String queueName, boolean autoAck, Consumer consumer) throws MqException, IOException, InterruptedException {
// 先设置回调
if(this.consumer != null) {
throw new MqException("该 channel 已经设置过消费消息的回调了,不能重复设置!");
}
this.consumer = consumer;
BasicConsumeArguments basicConsumeArguments = new BasicConsumeArguments();
basicConsumeArguments.setRid(generateRid());
basicConsumeArguments.setChannelId(channelId);
// 此处 ConsumerTag 也使用 channelId 来表示
basicConsumeArguments.setConsumerTag(channelId);
basicConsumeArguments.setQueueName(queueName);
basicConsumeArguments.setAutoAck(autoAck);
byte[] payload = BinaryTool.toBytes(basicConsumeArguments);
Request request = new Request();
request.setType(0xa);
request.setLength(payload.length);
request.setPayload(payload);
connection.writeRequest(request);
BasicReturns basicReturns = waitResult(basicConsumeArguments.getRid());
return basicReturns.isOk();
}
针对 客户端 和 服务器 单元测试
编写测试用例代码是十分重要的!
package com.example.demo;
import com.example.demo.common.Consumer;
import com.example.demo.common.MqException;
import com.example.demo.mqclient.Channel;
import com.example.demo.mqclient.Connection;
import com.example.demo.mqclient.ConnectionFactory;
import com.example.demo.mqserver.BrokerServer;
import com.example.demo.mqserver.core.BasicProperties;
import com.example.demo.mqserver.core.ExchangeType;
import org.apache.tomcat.util.http.fileupload.FileUtils;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.springframework.boot.SpringApplication;
import java.io.File;
import java.io.IOException;
public class MqClientTests {
private BrokerServer brokerServer = null;
private ConnectionFactory connectionFactory = null;
private Thread t = null;
@BeforeEach
public void setUp() throws IOException {
// 1、先启动服务器
DemoApplication.context = SpringApplication.run(DemoApplication.class);
brokerServer = new BrokerServer(9090);
t = new Thread(() -> {
// 这个 start 方法会进入一个死循环,使用一个新的线程来运行 start 即可!
try {
brokerServer.start();
} catch (IOException e) {
e.printStackTrace();
}
});
t.start();
// 2、配置 ConnectionFactory
connectionFactory = new ConnectionFactory();
connectionFactory.setHost("127.0.0.1");
connectionFactory.setPort(9090);
}
@AfterEach
public void tearDown() throws IOException {
// 停止服务器
brokerServer.stop();
// t.join();
DemoApplication.context.close();
// 删除必要的文件
File file = new File("./data");
FileUtils.deleteDirectory(file);
connectionFactory = null;
}
@Test
public void testConnection() throws IOException {
Connection connection = connectionFactory.newConnection();
Assertions.assertNotNull(connection);
}
@Test
public void testChannel() throws IOException, InterruptedException {
Connection connection = connectionFactory.newConnection();
Assertions.assertNotNull(connection);
Channel channel = connection.createChannel();
Assertions.assertNotNull(channel);
}
@Test
public void testExchange() throws IOException, InterruptedException {
Connection connection = connectionFactory.newConnection();
Assertions.assertNotNull(connection);
Channel channel = connection.createChannel();
Assertions.assertNotNull(channel);
boolean ok = channel.exchangeDeclare("testExchange", ExchangeType.DIRECT,true,false,null);
Assertions.assertTrue(ok);
ok = channel.exchangeDelete("testExchange");
Assertions.assertTrue(ok);
// 此处稳妥起见,把该关闭的要进行关闭
channel.close();
connection.close();
}
@Test
public void testQueue() throws IOException, InterruptedException{
Connection connection = connectionFactory.newConnection();
Assertions.assertNotNull(connection);
Channel channel = connection.createChannel();
Assertions.assertNotNull(channel);
boolean ok = channel.queueDeclare("testQueue",true,false,false,null);
Assertions.assertTrue(ok);
ok = channel.queueDelete("testQueue");
Assertions.assertTrue(ok);
channel.close();
connection.close();
}
@Test
public void testBinding() throws IOException, InterruptedException{
Connection connection = connectionFactory.newConnection();
Assertions.assertNotNull(connection);
Channel channel = connection.createChannel();
Assertions.assertNotNull(channel);
boolean ok = channel.exchangeDeclare("testExchange", ExchangeType.DIRECT,true,false,null);
Assertions.assertTrue(ok);
ok = channel.queueDeclare("testQueue",true,false,false,null);
Assertions.assertTrue(ok);
ok = channel.queueBind("testQueue","testExchange","testBindingKey");
Assertions.assertTrue(ok);
ok = channel.queueUnbind("testQueue","testExchange");
Assertions.assertTrue(ok);
channel.close();
connection.close();
}
@Test
public void testMessage() throws IOException, InterruptedException, MqException {
Connection connection = connectionFactory.newConnection();
Assertions.assertNotNull(connection);
Channel channel = connection.createChannel();
Assertions.assertNotNull(channel);
boolean ok = channel.exchangeDeclare("testExchange", ExchangeType.DIRECT,true,false,null);
Assertions.assertTrue(ok);
ok = channel.queueDeclare("testQueue",true,false,false,null);
Assertions.assertTrue(ok);
byte[] requestBody = "hello".getBytes();
ok = channel.basicPublish("testExchange","testQueue",null,requestBody);
Assertions.assertTrue(ok);
channel.basicConsume("testQueue", true, new Consumer() {
@Override
public void handleDelivery(String consumerTag, BasicProperties basicProperties, byte[] body) throws MqException, IOException {
System.out.println("[消费数据] 开始!");
System.out.println("consumeTag = " + consumerTag);
System.out.println("basicProperties = " + basicProperties);
Assertions.assertArrayEquals(requestBody,body);
System.out.println("[消费数据] 结束!");
}
});
Assertions.assertTrue(ok);
Thread.sleep(500);
channel.close();
connection.close();
}
}
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