1.线程池的创建
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
//一个程序中只能有一个线程池
public class ThreadPoolDemo {
public static void main(String[] args) {
//public static ExecutorService newCachedThreadPool()创建一个可根据需要创建新线程的线程池,但是在以前构造的线程可用时将重用它们。线程存活时间是60s
ExecutorService threadPool = Executors.newCachedThreadPool();
//void execute(Runnable command)在未来某个时间执行给定的命令
Runnable command = new Runnable() {
@Override
public void run() {
System.out.println(Thread.currentThread().getName()+"执行了");
}
};
//threadPool.execute(command);
//public static ExecutorService newSingleThreadExecutor()创建只有一个线程的线程池。如果线程不显示的关闭,线程将一直存活着
threadPool = Executors.newSingleThreadExecutor();
//threadPool.execute(command);
//public static ExecutorService newFixedThreadPool(int nThreads)创建一个可重用固定线程数的线程池。如果线程不显示的关闭,线程将一直存活着
threadPool = Executors.newFixedThreadPool(1);
//threadPool.execute(command);
//threadPool.execute(command);
//关闭线程池:void shutdown()启动一次顺序关闭,执行以前提交的任务,但不接受新任务
//threadPool.shutdown();//等整个程序退出的时候需要把线程池关闭
//new Thread(command).start();//我们自己创建线程
ThreadPoolUtils.execute(command);//pool-4-thread-1执行了
ThreadPoolUtils.shutdown();
ThreadPoolUtils.execute(command);//pool-5-thread-1执行了
}
}
2.工具包 子类对象交由线程执行
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class ThreadPoolUtils {
private static ExecutorService threadPool = Executors.newCachedThreadPool();
/**
* 将Runnable子类对象交由线程池执行
*
* @param command
*/
public static void execute(Runnable command) {
// 判断线程池是否被关闭
if (threadPool.isShutdown()) {
// 如果线程池被关闭了,那么就新建一个线程池
threadPool = Executors.newCachedThreadPool();
execute(command);// 再次将任务交给线程池执行
} else {
threadPool.execute(command);
}
}
/**
* 关闭线程池
*/
public static void shutdown() {
threadPool.shutdown();
}
}
3.定时器的用法
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;
/*
* Timer:一种工具,线程用其安排以后在后台线程中执行的任务。可安排任务执行一次,或者定期重复执行。
* TimerTask:由 Timer 安排为一次执行或重复执行的任务。
*/
public class TimerDemo {
public static void main(String[] args) {
test2();
}
private static void test2() {
//public Timer()创建一个新计时器。相关的线程不 作为守护程序运行
Timer timer = new Timer();
//protected TimerTask()创建一个新的计时器任务
TimerTask task = new TimerTask() {
@Override
public void run() {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String time = sdf.format(new Date());
System.out.println(time);
}
};
/*
* public void schedule(TimerTask task,
long delay,
long period)安排指定的任务从指定的延迟后开始进行重复的固定延迟执行
参数:
task - 所要安排的任务。
delay - 执行任务前的延迟时间,单位是毫秒。
period - 执行各后续任务之间的时间间隔,单位是毫秒。
*/
timer.schedule(task, 0, 1000);
}
private static void test() {
//public Timer()创建一个新计时器。相关的线程不 作为守护程序运行
Timer timer = new Timer();
//protected TimerTask()创建一个新的计时器任务
TimerTask task = new TimerTask() {
@Override
public void run() {
System.out.println("定时器执行的任务");
}
};
/*
* public void schedule(TimerTask task,long delay)安排在指定延迟后执行指定的任务。
参数:
* task - 所要安排的任务。
* delay - 执行任务前的延迟时间,单位是毫秒。
*/
timer.schedule(task, 1000);
//public boolean cancel()取消此计时器任务
//task.cancel();//终止的是任务
//public void cancel()终止此计时器,丢弃所有当前已安排的任务
timer.cancel();//终止此计时器
task = new TimerTask() {
@Override
public void run() {
System.out.println("定时器执行的任务");
}
};
timer.schedule(task, 1000);
//一个定时器任务能不能被执行多次?不行的
//timer.schedule(task, 3000);//Task already scheduled or cancelled
}
//安排在指定延迟后执行指定的任务。
public void schedule(Runnable task,long delay){
//创建一个线程
new Thread(new Runnable() {
@Override
public void run() {
//延迟指定delay的时间
try {
Thread.sleep(delay);
task.run();//run方法就执行在子线程中
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}).start();
}
}
4.网络传输之UDP
server
import java.net.DatagramPacket;
import java.net.DatagramSocket;
//DatagramSocket:此类表示用来发送和接收数据包的套接字
public class Server {
public static void main(String[] args) throws Exception {
//1.创建Socket对象并监听指定的端口
DatagramSocket s = new DatagramSocket(8888);
//2.创建一个数据包容器用于存储数据,udp一次传输的数据包最大是64k
//public DatagramPacket(byte[] buf,int length) buf - 保存传入数据报的缓冲区。len - 要读取的字节数。
DatagramPacket p = new DatagramPacket(new byte[1024*64], 1024*64);
//3.接收数据
//public void receive(DatagramPacket p)从此套接字接收数据包
s.receive(p);
//4.拆开数据包,取出内容
//public byte[] getData()返回数据缓冲区
byte[] data = p.getData();
//public int getLength()返回将要发送或接收到的数据的长度
int len = p.getLength();//实际接收的字节个数
//将读取的内容转换成字符串
String content = new String(data,0,len);
String ip = p.getAddress().getHostAddress();
System.out.println("ip="+ip+0+",内容="+content);
//5.释放资源
s.close();
}
}
client
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
/*
* DatagramSocket:此类表示用来发送和接收数据包的套接字
* DatagramPacket:此类表示数据包
*/
public class Client {
public static void main(String[] args) throws Exception {
//1.创建Socket对象
//public DatagramSocket()构造数据报套接字并将其绑定到本地主机上任何可用的端口
DatagramSocket s = new DatagramSocket();
//2.构建要发送的数据包,在数据包中指定要发送的内容,发送目标的ip地址,端口号
//public DatagramPacket(byte[] buf,int length,InetAddress address,int port)构造数据报包,用来将长度为 length 的包发送到指定主机上的指定端口号
byte[] buf = "udp,我来了~".getBytes(); //包数据
int length = buf.length;//包长度
InetAddress address = InetAddress.getByName("192.168.3.54");//目的地址。
int port = 8888;//port
DatagramPacket p = new DatagramPacket(buf, length, address, port);
//3.发送数据包到服务端
//public void send(DatagramPacket p)从此套接字发送数据包
s.send(p);
//4.关闭资源
//public void close()关闭此数据报套接字。
s.close();
}
}
5.网络传输之TCP
server
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;
public class Server {
public static void main(String[] args) throws Exception {
//1.创建ServerSocket对象并监听指定的端口号
ServerSocket ss = new ServerSocket(8888);
//2.接受客户端的连接请求
//public Socket accept()侦听并接受到此套接字的连接。此方法在连接传入之前一直阻塞。
Socket s = ss.accept();
//3.获取字节读取流
InputStream in = s.getInputStream();
//4.读取数据
byte[] b = new byte[1024];
int len = in.read(b);//len是实际读取的字节个数
//把接收到的数据转换成字符串
String content = new String(b,0,len);
String ip = s.getInetAddress().getHostAddress();
System.out.println("ip="+ip+",内容="+content);
//5.关闭资源
s.close();//连接对象关闭
ss.close();//服务器关闭
}
}
clientimport java.io.OutputStream;
import java.net.Socket;
public class Client {
public static void main(String[] args) throws Exception {
// 1.创建Socket对象并指定ip地址和端口号
Socket s = new Socket("192.168.3.54", 8888);
// 2.获取字节输出流
OutputStream out = s.getOutputStream();
// 3.写出数据到服务端
out.write("tcp,我来了~".getBytes());
// 4.关闭资源
s.close();
}
}
6.
服务器给客户端反馈内容
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.ServerSocket;
import java.net.Socket;
//服务器给客户端反馈内容
public class Server {
public static void main(String[] args) throws Exception {
// 1.创建ServerSocket对象并监听指定的端口号
ServerSocket ss = new ServerSocket(8888);
// 2.接收客户的请求
Socket s = ss.accept();
// 3.将字节读取流包装成字符缓冲读取流
InputStream in = s.getInputStream();
InputStreamReader isr = new InputStreamReader(in);
BufferedReader br = new BufferedReader(isr);
// 4.读取内容
String result = br.readLine();
System.out.println(result);
// 5.反馈结果给客户端,将字节输出流包装成字符缓冲输出流
OutputStream out = s.getOutputStream();
OutputStreamWriter osw = new OutputStreamWriter(out);
BufferedWriter bw = new BufferedWriter(osw);
// 6.将反馈结果返回给客户端
if (result.contains("钱")) {
bw.write("我也很穷啊,没钱");
bw.newLine();
bw.flush();
} else {
bw.write("我在啊,有啥事");
bw.newLine();
bw.flush();
}
// 7.关闭资源
s.close();
ss.close();
}
}
client
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.Socket;
public class Client {
public static void main(String[] args) throws Exception {
// 1.创建Socket对象并指定ip地址和端口号
Socket s = new Socket("192.168.3.54", 8888);
// 2.将获取的字节输出流包装成字符缓冲输出流
OutputStream out = s.getOutputStream();
OutputStreamWriter osw = new OutputStreamWriter(out);
BufferedWriter bw = new BufferedWriter(osw);
// 3.写出数据
bw.write("在吗?借点钱花花");
bw.newLine();
bw.flush();
// 4.获取服务端的返回消息,将字节读取流包装成字符缓冲读取流
InputStream in = s.getInputStream();
InputStreamReader isr = new InputStreamReader(in);
BufferedReader br = new BufferedReader(isr);
String result = br.readLine();
System.out.println(result);
// 5.关闭资源
s.close();
}
}
7.
客户端键盘录入内容,服务器输出到控制台
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
//客户端键盘录入内容,服务器输出到控制台
public class Server {
public static void main(String[] args) throws Exception {
// 1.创建ServerSocket对象并监听指定的端口号
ServerSocket ss = new ServerSocket(8888);
// 2.接受客户端的请求
while (true) {// 可以一直接受客户端的请求
Socket s = ss.accept();//阻塞式
// 3.将字节读取流包装成字符缓冲读取流
BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));
String line;// 用于保存每次读取的内容
while ((line = br.readLine()) != null) {
System.out.println(line);
}
// 4.关闭请求资源
s.close();
}
}
}
client
import java.io.BufferedWriter;
import java.io.OutputStreamWriter;
import java.net.Socket;
import java.util.Scanner;
//客户端键盘录入内容,服务器输出到控制台
public class Client {
public static void main(String[] args) throws Exception {
// 1.创建Socket对象并指定ip地址和端口号
Socket s = new Socket("192.168.3.54", 8888);
// 2.将字节输出流包装成字符缓冲输出流
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));
// 3.键盘录入数据,输出到服务端
Scanner sc = new Scanner(System.in);
while (true) {
String content = sc.nextLine();
if (content.equals("886")) {
break;
}
// 4.写出内容到服务端
bw.write(content);
bw.newLine();
bw.flush();
}
// 5.关闭资源
s.close();
}
}
8.客户端上传文件,服务器端保存起来
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.net.Socket;
//客户端上传文件,服务端保存起来
public class UploadClient {
public static void main(String[] args) throws Exception {
// 1.创建Socket对象并指定ip地址和端口号
Socket s = new Socket("192.168.3.54", 8888);
// 2.因为上传的文件类型不确定,所以将字节输出流包装成字节缓冲输出流
BufferedOutputStream bos = new BufferedOutputStream(s.getOutputStream());
// 3.将要上传的文件封装到字节缓冲读取流中
BufferedInputStream bis = new BufferedInputStream(new FileInputStream("E:/悟空.jpg"));
// 4.循环的读写
byte[] buf = new byte[1024];
int len;
while ((len = bis.read(buf)) != -1) {
bos.write(buf, 0, len);
}
// 5.将数据刷新到服务端并且告诉服务端数据发送完毕
bos.flush();
s.shutdownOutput();//禁用此套接字的输出流
// 6.接收服务端的返回结果,将字节读取流包装成字符缓冲读取流
BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));
System.out.println(br.readLine());
// 7.关闭资源
bis.close();// 自己创建的资源
s.close();
}
}
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedWriter;
import java.io.FileOutputStream;
import java.io.OutputStreamWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.UUID;
public class UploadServer {
public static void main(String[] args) throws Exception {
// 1.创建ServerSocket对象并监听指定的端口号
ServerSocket ss = new ServerSocket(8888);
// 2.接收客户端请求连接
while (true) {// 一直接收客户端的请求
Socket s = ss.accept();
// 3.将字节读取流包装成字节缓冲读取流
BufferedInputStream bis = new BufferedInputStream(s.getInputStream());
// 4.将要保存的字节数据写出到一个文件中,创建字节缓冲输出流
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("D:/" + getUUID() + ".jpg"));
// 5.循环读写
byte[] buf = new byte[1024];
int len;
while ((len = bis.read(buf)) != -1) {
bos.write(buf, 0, len);
}
// 6.将数据刷新到硬盘
bos.flush();
// 7.将上传结果返回给客户端,将字节输出流封装成字符缓冲输出流
System.out.println("上传文件成功");
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));
bw.write("上传文件成功");
bw.newLine();
bw.flush();
// 8.关闭资源
bos.close();//自己创建的资源关闭
s.close();//请求对象关闭
}
}
public static String getUUID() {
return UUID.randomUUID().toString().replaceAll("-", "");
}
}
9.
server
import java.net.ServerSocket;
import java.net.Socket;
public class UploadServer {
public static void main(String[] args) throws Exception {
// 1.创建ServerSocket对象并监听指定的端口号
ServerSocket ss = new ServerSocket(8888);
// 2.接收客户端请求连接
while (true) {// 一直接收客户端的请求
Socket s = ss.accept();
//接收到请求任务之后,将任务交给子线程来处理,因为可能有多个请求,所以需要启动多个子线程,所以使用线程池比较合理
ThreadPoolUtils.execute(new ServerRunnable(s));
}
}
}
client//客户端上传文件,服务端保存起来
public class UploadClient {
public static void main(String[] args) throws Exception {
ThreadPoolUtils.execute(new ClientRunnable("192.168.3.54", 8888, "E:/修仙.txt"));
ThreadPoolUtils.execute(new ClientRunnable("192.168.3.54", 8888, "E:/修仙.txt"));
ThreadPoolUtils.execute(new ClientRunnable("192.168.3.54", 8888, "E:/修仙.txt"));
ThreadPoolUtils.execute(new ClientRunnable("192.168.3.54", 8888, "E:/修仙.txt"));
}
}
ServerRunnable
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedWriter;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.net.Socket;
import java.util.UUID;
public class ServerRunnable implements Runnable {
private Socket s;
public ServerRunnable(Socket s) {
super();
this.s = s;
}
@Override
public void run() {
try {
// 3.将字节读取流包装成字节缓冲读取流
BufferedInputStream bis = new BufferedInputStream(s.getInputStream());
// 4.将要保存的字节数据写出到一个文件中,创建字节缓冲输出流
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("D:/" + getUUID() + ".txt"));
// 5.循环读写
byte[] buf = new byte[1024];
int len;
while ((len = bis.read(buf)) != -1) {
bos.write(buf, 0, len);
}
// 6.将数据刷新到硬盘
bos.flush();
// 7.将上传结果返回给客户端,将字节输出流封装成字符缓冲输出流
System.out.println("上传文件成功");
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));
bw.write("上传文件成功");
bw.newLine();
bw.flush();
// 8.关闭资源
bos.close();// 自己创建的资源关闭
} catch (Exception e) {
e.printStackTrace();
} finally {
if (null != s) {
try {
s.close();
} catch (IOException e) {
e.printStackTrace();
} // 请求对象关闭
}
}
}
public static String getUUID() {
return UUID.randomUUID().toString().replaceAll("-", "");
}
}
ThreadPoolUtilsimport java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class ThreadPoolUtils {
private static ExecutorService threadPool = Executors.newCachedThreadPool();
public static void execute(Runnable command) {
threadPool.execute(command);
}
}
ClientRunnableimport java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.net.Socket;
public class ClientRunnable implements Runnable {
private String ip;
private int port;
private String uploadPath;
public ClientRunnable(String ip, int port, String uploadPath) {
super();
this.ip = ip;
this.port = port;
this.uploadPath = uploadPath;
}
@Override
public void run() {
try (// 1.创建Socket对象并指定ip地址和端口号
Socket s = new Socket(ip, port);
// 3.将要上传的文件封装到字节缓冲读取流中
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(uploadPath));) {
// 2.因为上传的文件类型不确定,所以将字节输出流包装成字节缓冲输出流
BufferedOutputStream bos = new BufferedOutputStream(s.getOutputStream());
// 4.循环的读写
byte[] buf = new byte[1024];
int len;
while ((len = bis.read(buf)) != -1) {
bos.write(buf, 0, len);
}
// 5.将数据刷新到服务端并且告诉服务端数据发送完毕
bos.flush();
s.shutdownOutput();// 禁用此套接字的输出流
// 6.接收服务端的返回结果,将字节读取流包装成字符缓冲读取流
BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));
System.out.println(br.readLine());
} catch (Exception e) {
e.printStackTrace();
}
}
}
inetAddressDemo
import java.net.InetAddress;
public class InetAddressDemo {
public static void main(String[] args) throws Exception {
//public static InetAddress getByName(String host)在给定主机名的情况下确定主机的 IP 地址。
InetAddress inetAddress = InetAddress.getByName("www.taobao.cn");
//public String getHostAddress()返回 IP 地址字符串(以文本表现形式)。
String ip = inetAddress.getHostAddress();
System.out.println(ip);//192.168.3.106
//public String getHostName()获取此 IP 地址的主机名。
String hostName = inetAddress.getHostName();
System.out.println(hostName);//LENOVO-PC
//public static InetAddress getLocalHost()返回本地主机
InetAddress localHost = InetAddress.getLocalHost();
System.out.println(localHost.getHostAddress());//192.168.200.1
System.out.println(localHost.getHostName());//DESKTOP-NT06AQ5
}
}
10.聊天室
client
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.util.Scanner;
public class Client {
public static void main(String[] args) throws Exception {
// 1.创建Socket对象
DatagramSocket s = new DatagramSocket();
// 2.构建数据包,内容应该是键盘录入
Scanner sc = new Scanner(System.in);
byte[] bytes;
DatagramPacket p;
while (true) {
String content = sc.nextLine();
// 如果用户输入886就表示结束输入
if (content.equals("886")) {
break;
}
bytes = content.getBytes();
p = new DatagramPacket(bytes, bytes.length, InetAddress.getByName("192.168.3.255"), 8888);
// 3.发送数据包
s.send(p);
}
// 3.关闭资源
s.close();
}
}
ClientRunnable
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.util.Scanner;
public class ClientRunnable implements Runnable {
private String ip;
private int port;
public ClientRunnable(String ip, int port) {
super();
this.ip = ip;
this.port = port;
}
@Override
public void run() {
try (// 1.创建Socket对象
DatagramSocket s = new DatagramSocket();) {
// 2.构建数据包,内容应该是键盘录入
Scanner sc = new Scanner(System.in);
byte[] bytes;
DatagramPacket p;
while (true) {
String content = sc.nextLine();
// 如果用户输入886就表示结束输入
if (content.equals("886")) {
break;
}
bytes = content.getBytes();
p = new DatagramPacket(bytes, bytes.length, InetAddress.getByName(ip), port);
// 3.发送数据包
s.send(p);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
chatroom
public class ChatRoom {
public static void main(String[] args) {
ServerRunnable serverRunnable = new ServerRunnable(8888);
ClientRunnable clientRunnable = new ClientRunnable("192.168.3.255", 8888);
ThreadPoolUtils.execute(serverRunnable);
ThreadPoolUtils.execute(clientRunnable);
}
}
server
import java.net.DatagramPacket;
import java.net.DatagramSocket;
public class Server {
public static void main(String[] args) throws Exception {
// 1.创建Socket对象并监听指定的端口号
DatagramSocket s = new DatagramSocket(8888);
// 2.创建存放数据的数据包
DatagramPacket p = new DatagramPacket(new byte[1024 * 64], 1024 * 64);
// 3.循环的接收数据
byte[] data;
int len;
String content;
String ip;
while (true) {
s.receive(p);
// 4.从包中取出内容
data = p.getData();// 获取缓冲区
len = p.getLength();// 获取实际的字节个数
// 把接收的字节变成字符串
content = new String(data, 0, len);
ip = p.getAddress().getHostAddress();
System.out.println("ip=" + ip + ",内容=" + content);
}
}
}
ServerRunnable
import java.net.DatagramPacket;
import java.net.DatagramSocket;
public class ServerRunnable implements Runnable {
private int port;
public ServerRunnable(int port) {
super();
this.port = port;
}
@Override
public void run() {
try (// 1.创建Socket对象并监听指定的端口号
DatagramSocket s = new DatagramSocket(port);) {
// 2.创建存放数据的数据包
DatagramPacket p = new DatagramPacket(new byte[1024 * 64], 1024 * 64);
// 3.循环的接收数据
byte[] data;
int len;
String content;
String ip;
while (true) {
s.receive(p);
// 4.从包中取出内容
data = p.getData();// 获取缓冲区
len = p.getLength();// 获取实际的字节个数
// 把接收的字节变成字符串
content = new String(data, 0, len);
ip = p.getAddress().getHostAddress();
System.out.println("ip=" + ip + ",内容=" + content);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
ThreadPoolUtils
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class ThreadPoolUtils {
private static ExecutorService threadPool = Executors.newCachedThreadPool();
public static void execute(Runnable command) {
threadPool.execute(command);
}
}
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