BIO概念
Java BIO (blocking I/O): 同步并阻塞,服务器实现模式为一个连接一个线程,即客户端有连接请求时服务器端就需要启动一个线程进行处理,如果这个连接不做任何事情会造成不必要的线程开销
使用场景
BIO方式适用于连接数目比较小且固定的架构,这种方式对服务器资源要求比较高,并发局限于应用中,JDK1.4以前的唯一选择,但程序直观简单易理解。
聊天室
- 需要一个服务端
- 一个或多个客户端
服务端
- 当前服务端可以接收客户端数据
- 同时能够向客户端写入数据
package com.milla.study.netbase.expert.netty.io.bio;
import lombok.extern.slf4j.Slf4j;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
/**
* @Description: <服务端>
* @Author: milla
* @CreateDate: 2020/08/06 15:47
* @UpdateUser: milla
* @UpdateDate: 2020/08/06 15:47
* @UpdateRemark: <>
* @Version: 1.0
*/
@Slf4j
public class Server {
public static void main(String[] args) throws IOException {
server();
}
private static void server() throws IOException {
//启动服务指定端口
ServerSocket server = new ServerSocket(10010);
//接收进来一个客户端
Socket client = server.accept();
//获取客户端的输入流-获取客户端数据
BufferedReader reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
//获取客户端输出流-将数据写向客户端
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));
String requestLine;
while ((requestLine = reader.readLine()) != null) {
log.info("客户端:{} ,数据:{}", client, requestLine);
writer.write(requestLine);
//刷新流数据
writer.flush();
}
//关闭资源
reader.close();
server.close();
}
}
客户端
package com.milla.study.netbase.expert.netty.io.bio;
import lombok.extern.slf4j.Slf4j;
import java.io.*;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.util.UUID;
/**
* @Description: <客户端>
* @Author: milla
* @CreateDate: 2020/08/06 15:52
* @UpdateUser: milla
* @UpdateDate: 2020/08/06 15:52
* @UpdateRemark: <>
* @Version: 1.0
*/
@Slf4j
public class Client {
public static void main(String[] args) throws IOException {
client();
}
private static void client() throws IOException {
//创建一个客户端
Socket client = new Socket();
//连接指定的的服务地址及端口
client.connect(new InetSocketAddress("localhost", 10010));
//获取一个输出流-向服务写入数据
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));
//随机的uuid数据
writer.write(UUID.randomUUID().toString());
//刷新数据并关闭资源
writer.flush();
//接收信息
getMessage(client);
writer.close();
client.close();
}
private static void getMessage(Socket client) {
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
String line;
while (!client.isClosed() && (line = reader.readLine()) != null) {
log.info("接收到的数据为:{}", line);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
# 启动之后服务端是可以收到数据的
16:23:36.534 [main] INFO com.milla.study.netbase.expert.netty.io.bio.Server - 服务启动中.......
16:23:46.970 [main] INFO com.milla.study.netbase.expert.netty.io.bio.Server - 服务接收到一个连接: Socket[addr=/127.0.0.1,port=49600,localport=10010]
# 此时会有个问题,就是当客户端关闭的时候,服务端也会自动关闭,所以需要对服务端进行改进
改进后代码
package com.milla.study.netbase.expert.netty.io.bio;
import lombok.extern.slf4j.Slf4j;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
/**
* @Description: <服务端>
* @Author: milla
* @CreateDate: 2020/08/06 15:47
* @UpdateUser: milla
* @UpdateDate: 2020/08/06 15:47
* @UpdateRemark: <>
* @Version: 1.0
*/
@Slf4j
public class Server {
public static void main(String[] args) throws IOException {
server();
}
private static void server() throws IOException {
log.info("服务启动中.......");
//启动服务指定端口
ServerSocket server = new ServerSocket(10010);
//只要服务端不关闭,那么就一直执行
while (!server.isClosed()) {
BufferedReader reader = null;
try {
//接收进来一个客户端
Socket client = server.accept();
log.info("服务接收到一个连接: {}", client);
//获取客户端的输入流-获取客户端数据
reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
//获取客户端输出流-将数据写向客户端
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));
String requestLine;
while (!client.isInputShutdown() && (requestLine = reader.readLine()) != null) {
log.info("客户端:{} ,数据:{}", client, requestLine);
writer.write(requestLine);
writer.newLine();
//刷新流数据
writer.flush();
}
} catch (IOException e) {
log.error("Exception");
} finally {
//关闭资源
if (reader != null) {
reader.close();
}
}
}
server.close();
}
}
# 此时发现客户端只能发送数据,实际并不能接收数据
# 原因是因为bio中获取输入流和输出流都是阻塞的,所以,使用两个线程进行读写,解决该问题
package com.milla.study.netbase.expert.netty.io.bio;
import lombok.extern.slf4j.Slf4j;
import java.io.*;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.util.UUID;
/**
* @Description: <客户端>
* @Author: milla
* @CreateDate: 2020/08/06 15:52
* @UpdateUser: milla
* @UpdateDate: 2020/08/06 15:52
* @UpdateRemark: <>
* @Version: 1.0
*/
@Slf4j
public class Client {
public static void main(String[] args) throws IOException {
client();
}
private static void client() throws IOException {
//创建一个客户端
Socket client = new Socket();
//连接指定的的服务地址及端口
client.connect(new InetSocketAddress("localhost", 10010));
//异步发送信息
new Thread(() -> sendMessage(client), "send").start();
//接收信息
getMessage(client);
client.close();
}
private static void sendMessage(Socket client) {
try {
//获取输出流-写向服务端
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));
//写一个随机字符串
writer.write(UUID.randomUUID().toString());
writer.newLine();
writer.flush();
} catch (IOException e) {
e.printStackTrace();
}
}
private static void getMessage(Socket client) {
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
String line;
while (!client.isClosed() && (line = reader.readLine()) != null) {
log.info("接收到的数据为:{}", line);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
# 数据不能是随机的数据,需要用户自定义的数据,那就是用Scanner输入流进行模拟吧
package com.milla.study.netbase.expert.netty.io.bio;
import lombok.extern.slf4j.Slf4j;
import java.io.*;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.util.Scanner;
/**
* @Description: <客户端>
* @Author: milla
* @CreateDate: 2020/08/06 15:52
* @UpdateUser: milla
* @UpdateDate: 2020/08/06 15:52
* @UpdateRemark: <>
* @Version: 1.0
*/
@Slf4j
public class Client {
public static void main(String[] args) throws IOException {
client();
}
private static void client() throws IOException {
//创建一个客户端
Socket client = new Socket();
//连接指定的的服务地址及端口
client.connect(new InetSocketAddress("localhost", 10010));
//异步发送信息
new Thread(() -> sendMessage(client), "send").start();
//接收信息
getMessage(client);
client.close();
}
private static void sendMessage(Socket client) {
try {
//获取输出流-写向服务端
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));
Scanner scanner = new Scanner(System.in);
String requestLine = null;
//当输出quit的时候,代表客户端要下线,不再进行通信了
while (!"quit".equals(requestLine)) {
System.out.println("输入<》:");
//获取一行数据
requestLine = scanner.nextLine();
writer.write(requestLine);
writer.newLine();
writer.flush();
}
} catch (IOException e) {
e.printStackTrace();
}
}
private static void getMessage(Socket client) {
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
String line;
while (!client.isClosed() && (line = reader.readLine()) != null) {
log.info("接收到的数据为:{}", line);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
# 那么此时就可以考虑多客户端问题了,但是将client复制以后会发现,实际上server并不能识别
# 原因很简单,client.getOutputStream()是阻塞的,没有处理完不会退出
# 所以采用线程池来解决这个问题
package com.milla.study.netbase.expert.netty.io.bio;
import lombok.extern.slf4j.Slf4j;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
/**
* @Description: <服务端>
* @Author: milla
* @CreateDate: 2020/08/06 15:47
* @UpdateUser: milla
* @UpdateDate: 2020/08/06 15:47
* @UpdateRemark: <>
* @Version: 1.0
*/
@Slf4j
public class Server {
public static void main(String[] args) throws IOException {
server();
}
private static void server() throws IOException {
//创建一个线程池,-最多能处理33个连接
ThreadPoolExecutor pool = new ThreadPoolExecutor(3, 30, 5000, TimeUnit.MILLISECONDS, new ArrayBlockingQueue<>(3), (a, b) -> System.out.println("自定义"));
log.info("服务启动中.......");
//启动服务指定端口
ServerSocket server = new ServerSocket(10010);
//只要服务端不关闭,那么就一直执行
while (!server.isClosed()) {
Socket client = server.accept();
pool.submit(() -> getClient(client));
}
server.close();
}
private static void getClient(Socket client) {
BufferedReader reader = null;
try {
//接收进来一个客户端
log.info("服务接收到一个连接: {}", client);
//获取客户端的输入流-获取客户端数据
reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
//获取客户端输出流-将数据写向客户端
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));
String requestLine;
while (!client.isInputShutdown() && (requestLine = reader.readLine()) != null) {
log.info("客户端:{} ,数据:{}", client, requestLine);
writer.write(requestLine);
writer.newLine();
//刷新流数据
writer.flush();
}
} catch (IOException e) {
log.error("Exception");
} finally {
//关闭资源
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
# 此时已经可以处理多个连接
17:01:58.246 [pool-1-thread-1] INFO com.milla.study.netbase.expert.netty.io.bio.Server - 服务接收到一个连接: Socket[addr=/127.0.0.1,port=50837,localport=10010]
17:02:11.825 [pool-1-thread-2] INFO com.milla.study.netbase.expert.netty.io.bio.Server - 服务接收到一个连接: Socket[addr=/127.0.0.1,port=50850,localport=10010]
# 优化服务端保存连接信息
package com.milla.study.netbase.expert.netty.io.bio;
import lombok.extern.slf4j.Slf4j;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
/**
* @Description: <服务端>
* @Author: milla
* @CreateDate: 2020/08/06 15:47
* @UpdateUser: milla
* @UpdateDate: 2020/08/06 15:47
* @UpdateRemark: <>
* @Version: 1.0
*/
@Slf4j
public class Server {
/**
* 存储客户端信息
*/
private static final Map<Socket, Object> clients = new ConcurrentHashMap<>(100);
public static void main(String[] args) throws IOException {
server();
}
private static void server() throws IOException {
//创建一个线程池,-最多能处理33个连接
ThreadPoolExecutor pool = new ThreadPoolExecutor(3, 30, 5000, TimeUnit.MILLISECONDS, new ArrayBlockingQueue<>(3), (a, b) -> System.out.println("自定义"));
log.info("服务启动中.......");
//启动服务指定端口
ServerSocket server = new ServerSocket(10010);
//只要服务端不关闭,那么就一直执行
while (!server.isClosed()) {
Socket client = server.accept();
// value可以是以后需要统计信息,这里暂时使用client对象
clients.putIfAbsent(client, client);
pool.submit(() -> getClient(client));
}
server.close();
}
private static void getClient(Socket client) {
BufferedReader reader = null;
try {
//接收进来一个客户端
log.info("服务接收到一个连接: {}", client);
//获取客户端的输入流-获取客户端数据
reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
//获取客户端输出流-将数据写向客户端
String requestLine;
while (!client.isInputShutdown() && (requestLine = reader.readLine()) != null) {
if ("quit".equals(requestLine)) {
log.info("客户端: {},退出连接", client);
clients.remove(client);
break;
}
senderMessages2Clients(requestLine, client);
log.info("客户端:{} 数据为:{}", client, requestLine);
}
} catch (IOException e) {
log.error("Exception");
} finally {
//关闭资源
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
private static void senderMessages2Clients(String line, Socket socket) {
if (clients.isEmpty()) {
return;
}
Set<Map.Entry<Socket, Object>> entries = clients.entrySet();
entries.stream().filter(item -> !item.getKey().isClosed()).forEach((item -> {
Socket client = item.getKey();
try {
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));
writer.write(socket.getPort() + " - " + line);
writer.newLine();
writer.flush();
} catch (IOException e) {
e.printStackTrace();
}
}));
}
}
# 至此,开多个客户端,客户端就可以进行通信了
package com.milla.study.netbase.expert.netty.io.bio;
import lombok.extern.slf4j.Slf4j;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
/**
* @Description: <服务端>
* @Author: milla
* @CreateDate: 2020/08/06 15:47
* @UpdateUser: milla
* @UpdateDate: 2020/08/06 15:47
* @UpdateRemark: <>
* @Version: 1.0
*/
@Slf4j
public class Server {
/**
* 存储客户端信息
*/
private static final Map<Socket, Object> clients = new ConcurrentHashMap<>(100);
public static void main(String[] args) throws IOException {
server();
}
private static void server() throws IOException {
//创建一个线程池,-最多能处理33个连接
ThreadPoolExecutor pool = new ThreadPoolExecutor(3, 30, 5000, TimeUnit.MILLISECONDS, new ArrayBlockingQueue<>(3), (a, b) -> System.out.println("自定义"));
log.info("服务启动中.......");
//启动服务指定端口
ServerSocket server = new ServerSocket(10010);
//只要服务端不关闭,那么就一直执行
while (!server.isClosed()) {
Socket client = server.accept();
// value可以是以后需要统计信息,这里暂时使用client对象
clients.putIfAbsent(client, client);
pool.submit(() -> getClient(client));
}
server.close();
}
private static void getClient(Socket client) {
BufferedReader reader = null;
try {
//接收进来一个客户端
log.info("服务接收到一个连接: {}", client);
//获取客户端的输入流-获取客户端数据
reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
//获取客户端输出流-将数据写向客户端
String requestLine;
while (!client.isInputShutdown() && (requestLine = reader.readLine()) != null) {
if ("quit".equals(requestLine)) {
log.info("客户端: {},退出连接", client);
clients.remove(client);
break;
}
senderMessages2Clients(requestLine, client);
log.info("客户端:{} 数据为:{}", client, requestLine);
}
} catch (IOException e) {
log.error("Exception");
} finally {
//关闭资源
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
private static void senderMessages2Clients(String line, Socket socket) {
if (clients.isEmpty()) {
return;
}
Set<Map.Entry<Socket, Object>> entries = clients.entrySet();
entries.stream().filter(item -> !item.getKey().isClosed()).forEach((item -> {
Socket client = item.getKey();
try {
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));
writer.write(socket.getPort() + " - " + line);
writer.newLine();
writer.flush();
} catch (IOException e) {
e.printStackTrace();
}
}));
}
}
效果图
完整代码
服务端
package com.milla.study.netbase.expert.netty.io.bio;
import lombok.extern.slf4j.Slf4j;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
/**
* @Description: <服务端>
* @Author: milla
* @CreateDate: 2020/08/06 15:47
* @UpdateUser: milla
* @UpdateDate: 2020/08/06 15:47
* @UpdateRemark: <>
* @Version: 1.0
*/
@Slf4j
public class Server {
/**
* 存储客户端信息
*/
private static final Map<Socket, Object> clients = new ConcurrentHashMap<>(100);
public static void main(String[] args) throws IOException {
server();
}
private static void server() throws IOException {
//创建一个线程池,-最多能处理33个连接
ThreadPoolExecutor pool = new ThreadPoolExecutor(3, 30, 5000, TimeUnit.MILLISECONDS, new ArrayBlockingQueue<>(3), (a, b) -> System.out.println("自定义"));
log.info("服务启动中.......");
//启动服务指定端口
ServerSocket server = new ServerSocket(10010);
//只要服务端不关闭,那么就一直执行
while (!server.isClosed()) {
Socket client = server.accept();
// value可以是以后需要统计信息,这里暂时使用client对象
clients.putIfAbsent(client, client);
pool.submit(() -> getClient(client));
}
server.close();
}
private static void getClient(Socket client) {
BufferedReader reader = null;
try {
//接收进来一个客户端
log.info("服务接收到一个连接: {}", client);
//获取客户端的输入流-获取客户端数据
reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
//获取客户端输出流-将数据写向客户端
String requestLine;
while (!client.isInputShutdown() && (requestLine = reader.readLine()) != null) {
if ("quit".equals(requestLine)) {
log.info("客户端: {},退出连接", client);
clients.remove(client);
client.shutdownInput();
client.shutdownOutput();
break;
}
senderMessages2Clients(requestLine, client);
log.info("客户端:{} 数据为:{}", client, requestLine);
}
} catch (IOException e) {
log.error("Exception");
} finally {
//关闭资源
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
private static void senderMessages2Clients(String line, Socket socket) {
if (clients.isEmpty()) {
return;
}
Set<Map.Entry<Socket, Object>> entries = clients.entrySet();
entries.stream().filter(item -> !item.getKey().isClosed()).forEach((item -> {
Socket client = item.getKey();
try {
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));
writer.write(socket.getPort() + " - " + line);
writer.newLine();
writer.flush();
} catch (IOException e) {
e.printStackTrace();
}
}));
}
}
客户端
package com.milla.study.netbase.expert.netty.io.bio;
import lombok.extern.slf4j.Slf4j;
import java.io.*;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.util.Scanner;
/**
* @Description: <客户端>
* @Author: milla
* @CreateDate: 2020/08/06 15:52
* @UpdateUser: milla
* @UpdateDate: 2020/08/06 15:52
* @UpdateRemark: <>
* @Version: 1.0
*/
@Slf4j
public class Client {
public static void main(String[] args) throws IOException {
client();
}
private static void client() throws IOException {
//创建一个客户端
Socket client = new Socket();
//连接指定的的服务地址及端口
client.connect(new InetSocketAddress("localhost", 10010));
//异步发送信息
new Thread(() -> sendMessage(client), "send").start();
//接收信息
getMessage(client);
client.close();
}
private static void sendMessage(Socket client) {
try {
//获取输出流-写向服务端
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));
Scanner scanner = new Scanner(System.in);
String requestLine = null;
//当输出quit的时候,代表客户端要下线,不再进行通信了
while (!"quit".equals(requestLine)) {
System.out.println("输入<》:");
//获取一行数据
requestLine = scanner.nextLine();
writer.write(requestLine);
writer.newLine();
writer.flush();
}
} catch (IOException e) {
e.printStackTrace();
}
}
private static void getMessage(Socket client) {
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
String line;
while (!client.isClosed() && (line = reader.readLine()) != null) {
log.info("聊天数据:{}", line);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}