网络编程--02 TCP
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3 TCP通信程序
3.1TCP发送数据
- java中的TCP通信
1、Java对基于TCP协议的的网络提供了良好的封装，使用Socket对象来代表两端的通信端口，并通过 Socket产生IO流来进行网络通信。
2、Java为客户端提供了Socket类，为服务器端提供了ServerSocket类 - 构造方法
- 相关方法
示例代码
public class ClientDemo {
public static void main(String[] args) throws IOException {
//创建客户端的Socket对象(Socket)
//Socket(String host, int port) 创建流套接字并将其连接到指定主机上的指定端口号
Socket s = new Socket("127.0.0.1",10000);
//获取输出流，写数据
//OutputStream getOutputStream() 返回此套接字的输出流
OutputStream os = s.getOutputStream();
os.write("hello,tcp,我来了".getBytes());
//释放资源
s.close();
}
}
3.2 TCP接受数据
- 构造方法
- 相关方法
注意事项：
- 三次握手和四次挥手
示例代码
public class ServerDemo {
public static void main(String[] args) throws IOException {
//创建服务器端的Socket对象(ServerSocket)
//ServerSocket(int port) 创建绑定到指定端口的服务器套接字
ServerSocket ss = new ServerSocket(10000);
//Socket accept() 侦听要连接到此套接字并接受它
Socket s = ss.accept();
//获取输入流，读数据，并把数据显示在控制台
InputStream is = s.getInputStream();
byte[] bys = new byte[1024];
int len = is.read(bys);
String data = new String(bys,0,len);
System.out.println("数据是：" + data);
//释放资源
s.close();
ss.close();
}
}
3.3 TCP程序练习
代码：
// 客户端
public class ClientDemo {
public static void main(String[] args) throws IOException {
Socket socket = new Socket("127.0.0.1",10000);
OutputStream os = socket.getOutputStream();
os.write("hello".getBytes());
// os.close();如果在这里关流,会导致整个socket都无法使用
socket.shutdownOutput();//仅仅关闭输出流.并写一个结束标记,对socket没有任何影响
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String line;
while((line = br.readLine())!=null){
System.out.println(line);
}
br.close();
os.close();
socket.close();
}
}
// 服务器
public class ServerDemo {
public static void main(String[] args) throws IOException {
ServerSocket ss = new ServerSocket(10000);
Socket accept = ss.accept();
InputStream is = accept.getInputStream();
int b;
while((b = is.read())!=-1){
System.out.println((char) b);
}
System.out.println("看看我执行了吗?");
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(accept.getOutputStream()));
bw.write("你谁啊?");
bw.newLine();
bw.flush();
bw.close();
is.close();
accept.close();
ss.close();
}
}
练习2：
// 客户端
public class ClientDemo {
public static void main(String[] args) throws IOException {
Socket socket = new Socket("127.0.0.1",10000);
//是本地的流,用来读取本地文件的.
BufferedInputStream bis = new BufferedInputStream(new FileInputStream("socketmodule\\\\ClientDir\\\\1.jpg"));
//写到服务器 --- 网络中的流
OutputStream os = socket.getOutputStream();
BufferedOutputStream bos = new BufferedOutputStream(os);
int b;
while((b = bis.read())!=-1){
bos.write(b);//通过网络写到服务器中
}
bos.flush();
//给服务器一个结束标记,告诉服务器文件已经传输完毕
socket.shutdownOutput();
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String line;
while((line = br.readLine()) !=null){
System.out.println(line);
}
bis.close();
socket.close();
}
}
// 服务器
public class ServerDemo {
public static void main(String[] args) throws IOException {
ServerSocket ss = new ServerSocket(10000);
Socket accept = ss.accept();
//网络中的流,从客户端读取数据的
BufferedInputStream bis = new BufferedInputStream(accept.getInputStream());
//本地的IO流,把数据写到本地中,实现永久化存储
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("socketmodule\\\\ServerDir\\\\copy.jpg"));
int b;
while((b = bis.read()) !=-1){
bos.write(b);
}
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(accept.getOutputStream()));
bw.write("上传成功");
bw.newLine();
bw.flush();
bos.close();
accept.close();
ss.close();
}
}
3.5 TCP程序服务器优化
- 优化1：
代码实现：
// 服务器代码如下,客户端代码同上个案例,此处不再给出
public class ServerDemo {
public static void main(String[] args) throws IOException {
ServerSocket ss = new ServerSocket(10000);
while (true) {
Socket accept = ss.accept();
//网络中的流,从客户端读取数据的
BufferedInputStream bis = new BufferedInputStream(accept.getInputStream());
//本地的IO流,把数据写到本地中,实现永久化存储
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("optimizeserver\\\\ServerDir\\\\copy.jpg"));
int b;
while((b = bis.read()) !=-1){
bos.write(b);
}
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(accept.getOutputStream()));
bw.write("上传成功");
bw.newLine();
bw.flush();
bos.close();
accept.close();
}
//ss.close();
}
}
- 优化2
代码实现：
// 服务器代码如下,客户端代码同上个案例,此处不再给出
public class ServerDemo {
public static void main(String[] args) throws IOException {
ServerSocket ss = new ServerSocket(10000);
while (true) {
Socket accept = ss.accept();
//网络中的流,从客户端读取数据的
BufferedInputStream bis = new BufferedInputStream(accept.getInputStream());
//本地的IO流,把数据写到本地中,实现永久化存储
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("optimizeserver\\\\ServerDir\\\\" + UUID.randomUUID().toString() + ".jpg"));
int b;
while((b = bis.read()) !=-1){
bos.write(b);
}
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(accept.getOutputStream()));
bw.write("上传成功");
bw.newLine();
bw.flush();
bos.close();
accept.close();
}
//ss.close();
}
}
- 优化3：
代码：
// 线程任务类
public class ThreadSocket implements Runnable {
private Socket acceptSocket;
public ThreadSocket(Socket accept) {
this.acceptSocket = accept;
}
@Override
public void run() {
BufferedOutputStream bos = null;
try {
//网络中的流,从客户端读取数据的
BufferedInputStream bis = new BufferedInputStream(acceptSocket.getInputStream());
//本地的IO流,把数据写到本地中,实现永久化存储
bos = new BufferedOutputStream(new FileOutputStream("optimizeserver\\\\ServerDir\\\\" + UUID.randomUUID().toString() + ".jpg"));
int b;
while((b = bis.read()) !=-1){
bos.write(b);
}
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(acceptSocket.getOutputStream()));
bw.write("上传成功");
bw.newLine();
bw.flush();
} catch (IOException e) {
e.printStackTrace();
} finally {
if(bos != null){
try {
bos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (acceptSocket != null){
try {
acceptSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
// 服务器代码
public class ServerDemo {
public static void main(String[] args) throws IOException {
ServerSocket ss = new ServerSocket(10000);
while (true) {
Socket accept = ss.accept();
ThreadSocket ts = new ThreadSocket(accept);
new Thread(ts).start();
}
//ss.close();
}
}
- 优化4:
// 服务器代码如下,线程任务类代码同上,此处不再给出
public class ServerDemo {
public static void main(String[] args) throws IOException {
ServerSocket ss = new ServerSocket(10000);
ThreadPoolExecutor pool = new ThreadPoolExecutor(
3,//核心线程数量
10, //线程池的总数量
60, //临时线程空闲时间
TimeUnit.SECONDS, //临时线程空闲时间的单位
new ArrayBlockingQueue<>(5),//阻塞队列
Executors.defaultThreadFactory(),//创建线程的方式
new ThreadPoolExecutor.AbortPolicy()//任务拒绝策略
);
while (true) {
Socket accept = ss.accept();
ThreadSocket ts = new ThreadSocket(accept);
//new Thread(ts).start();
pool.submit(ts);
}
//ss.close();
}
}
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