javaAPI_网络编程基础_网络编程基础2

Posted 2021-02-04 德墨特尔

网络编程基础2

1.TCP协议

(1).实现步骤
A:创建发送端的Socket对象
这一步如果成功，就说明连接已经建立成功了。
B:获取输出流，写数据
C:释放资源

连接被拒绝。TCP协议一定要先看服务器。
java.net.ConnectException: Connection refused: connect

(2).客户端
public static void main(String[] args) throws IOException {
// 创建发送端的Socket对象
// Socket(InetAddress address, int port)
// Socket(String host, int port)
// Socket s = new Socket(InetAddress.getByName("192.168.12.92"), 8888);
Socket s = new Socket("192.168.12.92", 8888);

// 获取输出流，写数据
// public OutputStream getOutputStream()
OutputStream os = s.getOutputStream();
os.write("hello,tcp,我来了".getBytes());

// 释放资源
s.close();
}

(3).服务器端接收数据步骤
A:创建接收端的Socket对象
B:监听客户端连接。返回一个对应的Socket对象
C:获取输入流，读取数据显示在控制台
D:释放资源

(4).代码实现
public static void main(String[] args) throws IOException {
// 创建接收端的Socket对象
// ServerSocket(int port)
ServerSocket ss = new ServerSocket(8888);

// 监听客户端连接。返回一个对应的Socket对象
// public Socket accept()
Socket s = ss.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。

// 获取输入流，读取数据显示在控制台
InputStream is = s.getInputStream();

byte[] bys = new byte[1024];
int len = is.read(bys); // 阻塞式方法
String str = new String(bys, 0, len);
//获取IP地址
String ip = s.getInetAddress().getHostAddress();

System.out.println(ip + "---" + str);

// 释放资源
s.close();
// ss.close(); //这个不应该关闭
}


(5).TCP协议接收发送数据图解

2.TCP协议常用案例

(1).客户端与服务器通信并且服务器端给客户端反馈

//服务器端
public static void main(String[] args) throws IOException {
// 创建服务器Socket对象
ServerSocket ss = new ServerSocket(9999);

// 监听客户端的连接
Socket s = ss.accept(); // 阻塞

// 获取输入流
InputStream is = s.getInputStream();
byte[] bys = new byte[1024];
int len = is.read(bys); // 阻塞
String server = new String(bys, 0, len);
System.out.println("server:" + server);

// 获取输出流
OutputStream os = s.getOutputStream();
os.write("数据已经收到".getBytes());

// 释放资源
s.close();
// ss.close();
}

//客户端
public static void main(String[] args) throws IOException {
// 创建客户端Socket对象
Socket s = new Socket("192.168.12.92", 9999);

// 获取输出流
OutputStream os = s.getOutputStream();
os.write("今天天气很好,适合睡觉".getBytes());

// 获取输入流
InputStream is = s.getInputStream();
byte[] bys = new byte[1024];
int len = is.read(bys);// 阻塞
String client = new String(bys, 0, len);
System.out.println("client:" + client);

// 释放资源
s.close();
}

(2).客户端键盘录入，服务器输出到控制台

//服务器端
public static void main(String[] args) throws IOException {
// 创建服务器Socket对象
ServerSocket ss = new ServerSocket(22222);

// 监听客户端连接
Socket s = ss.accept();

// 包装通道内容的流
BufferedReader br = new BufferedReader(new InputStreamReader(
s.getInputStream()));
String line = null;
while ((line = br.readLine()) != null) {
System.out.println(line);
}

// br.close();
s.close();
// ss.close();
}

//客户端
public static void main(String[] args) throws IOException {
// 创建客户端Socket对象
Socket s = new Socket("192.168.12.92", 22222);

// 键盘录入数据
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
// 把通道内的流给包装一下
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(
s.getOutputStream()));

String line = null;
while ((line = br.readLine()) != null) {
// 键盘录入数据要自定义结束标记
if ("886".equals(line)) {
break;
}
bw.write(line);
bw.newLine();
bw.flush();
}

// 释放资源
// bw.close();
// br.close();
s.close();
}

(3).客户端键盘录入，服务器输出文本文件

//服务器端
public static void main(String[] args) throws IOException {
// 创建服务器Socket对象
ServerSocket ss = new ServerSocket(23456);

// 监听客户端连接
Socket s = ss.accept();

// 封装通道内的数据
BufferedReader br = new BufferedReader(new InputStreamReader(
s.getInputStream()));
// 封装文本文件
BufferedWriter bw = new BufferedWriter(new FileWriter("a.txt"));

String line = null;
while ((line = br.readLine()) != null) {
bw.write(line);
bw.newLine();
bw.flush();
}

bw.close();
// br.close();
s.close();
// ss.close();
}

//客户端
public static void main(String[] args) throws IOException {
// 创建客户端Socket对象
Socket s = new Socket("192.168.12.92", 23456);

// 封装键盘录入
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
// 封装通道内的数据
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(
s.getOutputStream()));

String line = null;
while ((line = br.readLine()) != null) {
if ("over".equals(line)) {
break;
}

bw.write(line);
bw.newLine();
bw.flush();
}

// bw.close();
// br.close();
s.close();
}


3.TCP协议常用案例2

(1).TCP协议上传文本文件到服务器端

//客户端
public static void main(String[] args) throws IOException {
// 创建客户端Socket对象
Socket s = new Socket("192.168.12.92", 11111);

// 封装文本文件
BufferedReader br = new BufferedReader(new FileReader(
"InetAddressDemo.java"));
// 封装通道内流
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(
s.getOutputStream()));

String line = null;
while ((line = br.readLine()) != null) {
bw.write(line);
bw.newLine();
bw.flush();
}

// 释放资源
br.close();
s.close();
}

//服务器端
public static void main(String[] args) throws IOException {
// 创建服务器端的Socket对象
ServerSocket ss = new ServerSocket(11111);

// 监听客户端连接
Socket s = ss.accept();

// 封装通道内的流
BufferedReader br = new BufferedReader(new InputStreamReader(
s.getInputStream()));
// 封装文本文件
BufferedWriter bw = new BufferedWriter(new FileWriter("Copy.java"));

String line = null;
while ((line = br.readLine()) != null) {
bw.write(line);
bw.newLine();
bw.flush();
}

bw.close();
s.close();
}

(2).TCP协议上传文件并给反馈

注意问题:
按照我们正常的思路加入反馈信息，结果却没反应。为什么呢?
读取文本文件是可以以null作为结束信息的，但是呢，通道内是不能这样结束信息的。
所以，服务器根本就不知道你结束了。而你还想服务器给你反馈。所以，就相互等待了。

如何解决呢?
A:在多写一条数据，告诉服务器，读取到这条数据说明我就结束，你也结束吧。
这样做可以解决问题，但是不好。其实就是加了一个结束标识符
B:Socket对象提供了一种解决方案
public void shutdownOutput()

//客户端
public static void main(String[] args) throws IOException {
// 创建客户端Socket对象
Socket s = new Socket("192.168.12.92", 11111);

// 封装文本文件
BufferedReader br = new BufferedReader(new FileReader(
"InetAddressDemo.java"));
// 封装通道内流
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(
s.getOutputStream()));

String line = null;
while ((line = br.readLine()) != null) { // 阻塞
bw.write(line);
bw.newLine();
bw.flush();
}

//自定义一个结束标记
//bw.write("over");
//bw.newLine();
//bw.flush();

//Socket提供了一个终止，它会通知服务器你别等了，我没有数据过来了
s.shutdownOutput();

// 接收反馈
BufferedReader brClient = new BufferedReader(new InputStreamReader(
s.getInputStream()));
String client = brClient.readLine(); // 阻塞
System.out.println(client);

// 释放资源
br.close();
s.close();
}


//服务器端
public static void main(String[] args) throws IOException {
// 创建服务器端的Socket对象
ServerSocket ss = new ServerSocket(11111);

// 监听客户端连接
Socket s = ss.accept();// 阻塞

// 封装通道内的流
BufferedReader br = new BufferedReader(new InputStreamReader(
s.getInputStream()));
// 封装文本文件
BufferedWriter bw = new BufferedWriter(new FileWriter("Copy.java"));

String line = null;
while ((line = br.readLine()) != null) { // 阻塞
// if("over".equals(line)){
// break;
// }
bw.write(line);
bw.newLine();
bw.flush();
}

// 给出反馈
BufferedWriter bwServer = new BufferedWriter(new OutputStreamWriter(
s.getOutputStream()));
bwServer.write("文件上传成功");
bwServer.newLine();
bwServer.flush();

// 释放资源
bw.close();
s.close();
}

(3).上传图片到服务器并给反馈

//服务器端
public static void main(String[] args) throws IOException {
// 创建服务器Socket对象
ServerSocket ss = new ServerSocket(19191);

// 监听客户端连接
Socket s = ss.accept();

// 封装通道内流
BufferedInputStream bis = new BufferedInputStream(s.getInputStream());
// 封装图片文件
BufferedOutputStream bos = new BufferedOutputStream(
new FileOutputStream("mn.jpg"));

byte[] bys = new byte[1024];
int len = 0;
while ((len = bis.read(bys)) != -1) {
bos.write(bys, 0, len);
bos.flush();
}

// 给一个反馈
OutputStream os = s.getOutputStream();
os.write("图片上传成功".getBytes());

bos.close();
s.close();
}

//客户端反馈
public static void main(String[] args) throws IOException {
// 创建客户端Socket对象
Socket s = new Socket("192.168.12.92", 19191);

// 封装图片文件
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(
"林青霞.jpg"));
// 封装通道内的流
BufferedOutputStream bos = new BufferedOutputStream(s.getOutputStream());

byte[] bys = new byte[1024];
int len = 0;
while ((len = bis.read(bys)) != -1) {
bos.write(bys, 0, len);
bos.flush();
}

s.shutdownOutput();

// 读取反馈
InputStream is = s.getInputStream();
byte[] bys2 = new byte[1024];
int len2 = is.read(bys2);
String client = new String(bys2, 0, len2);
System.out.println(client);

// 释放资源
bis.close();
s.close();
}

4.TCP协议多客户端上传文件到一个服务器上案例[*****]

//客户端
public static void main(String[] args) throws IOException {
// 创建客户端Socket对象
Socket s = new Socket("192.168.12.92", 11111);

// 封装文本文件
// BufferedReader br = new BufferedReader(new FileReader(
// "InetAddressDemo.java"));
BufferedReader br = new BufferedReader(new FileReader(
"ReceiveDemo.java"));
// 封装通道内流
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(
s.getOutputStream()));

String line = null;
while ((line = br.readLine()) != null) { // 阻塞
bw.write(line);
bw.newLine();
bw.flush();
}

// Socket提供了一个终止，它会通知服务器你别等了，我没有数据过来了
s.shutdownOutput();

// 接收反馈
BufferedReader brClient = new BufferedReader(new InputStreamReader(
s.getInputStream()));
String client = brClient.readLine(); // 阻塞
System.out.println(client);

// 释放资源
br.close();
s.close();
}

//服务器端
public class UploadServer {
public static void main(String[] args) throws IOException {
// 创建服务器Socket对象
ServerSocket ss = new ServerSocket(11111);

while (true) {
Socket s = ss.accept();
new Thread(new UserThread(s)).start();
}
}
}

//用户线程端
public class UserThread implements Runnable {
private Socket s;

public UserThread(Socket s) {
this.s = s;
}

@Override
public void run() {
try {
// 封装通道内的流
BufferedReader br = new BufferedReader(new InputStreamReader(
s.getInputStream()));
// 封装文本文件
// BufferedWriter bw = new BufferedWriter(new
// FileWriter("Copy.java"));

// 为了防止名称冲突
String newName = System.currentTimeMillis() + ".java";
BufferedWriter bw = new BufferedWriter(new FileWriter(newName));

String line = null;
while ((line = br.readLine()) != null) { // 阻塞
bw.write(line);
bw.newLine();
bw.flush();
}

// 给出反馈
BufferedWriter bwServer = new BufferedWriter(
new OutputStreamWriter(s.getOutputStream()));
bwServer.write("文件上传成功");
bwServer.newLine();
bwServer.flush();

// 释放资源
bw.close();
s.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}