JAVA基础5(代码剖析)

时间：2023-02-15 18:18:55

代码选自善学堂

网络相关：

URL

</pre><pre class="java" name="code">import java.net.MalformedURLException;
import java.net.URL;

public class URLDemo01 {

/**
 * @param args
 * @throws MalformedURLException 
 */
public static void main(String[] args) throws MalformedURLException {
//绝对路径构建
URL url = new URL("http://www.baidu.com:80/index.html?uname=bjsxt");
System.out.println("协议:"+url.getProtocol());
System.out.println("域名:"+url.getHost());
System.out.println("端口:"+url.getPort());
System.out.println("资源:"+url.getFile());
System.out.println("相对路径:"+url.getPath());
System.out.println("锚点:"+url.getRef()); //锚点
System.out.println("参数:"+url.getQuery());//?参数 :存在锚点  返回null ,不存在，返回正确
url = new URL("http://www.baidu.com:80/a/");
url = new URL(url,"b.txt"); //相对路径
System.out.println(url.toString());

}

}


获取网页源码：

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.URL;

/**
 * 获取资源：源代码
 * @author Administrator
 *
 */
public class URLDemo02 {

/**
 * @param args
 * @throws IOException 
 */
public static void main(String[] args) throws IOException {
URL url = new URL("http://www.baidu.com"); //主页 默认资源
BufferedReader  br = 
new BufferedReader(new InputStreamReader(url.openStream(),"utf-8"));
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream("baidu2.html"),"utf-8"));

String msg =null;
while((msg=br.readLine())!=null){
//System.out.println(msg);
bw.append(msg);
bw.newLine();
}
bw.flush();

bw.close();
br.close();

}
}

//使用getLocalHost方法创建InetAddress对象
  InetAddress addr = InetAddress.getLocalHost();
  System.out.println(addr.getHostAddress());  //返回：192.168.1.100
  System.out.println(addr.getHostName());  //输出计算机名
  //根据域名得到InetAddress对象
  addr = InetAddress.getByName("www.163.com"); 
  System.out.println(addr.getHostAddress());  //返回 163服务器的ip:61.135.253.15
  System.out.println(addr.getHostName());  //输出：<a target=_blank href="http://www.163.com">www.163.com</a> 

/**
 * 封装端口:在InetAddress基础上+端口
 * @author Administrator
 *
 */
public class InetSockeDemo01 {

/**
 * @param args
 * @throws UnknownHostException 
 */
public static void main(String[] args) throws UnknownHostException {
InetSocketAddress  address = new InetSocketAddress("127.0.0.1",9999);
address = new InetSocketAddress(InetAddress.getByName("127.0.0.1"),9999);
System.out.println(address.getHostName());
System.out.println(address.getPort());
InetAddress addr =address.getAddress();
System.out.println(addr.getHostAddress());  //返回：地址
System.out.println(addr.getHostName());  //输出计算机名

}

}

UDP 编程 

import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;

/**
 * 客户端
 * 1、创建客户端 +端口
 * 2、准备数据   double -->字节数组   字节数组输出流
 * 3、打包（发送的地点 及端口）
 * 4、发送
 * 5、释放
 * 
 * 
 * @author Administrator
 *
 */
public class Client {

/**
 * @param args
 * @throws IOException 
 */
public static void main(String[] args) throws IOException {
//1、创建客户端 +端口
DatagramSocket client = new DatagramSocket(6666);
//2、准备数据
double num =89.12;
byte[] data =convert(num);
//3、打包（发送的地点 及端口） DatagramPacket(byte[] buf, int length, InetAddress address, int port)
DatagramPacket packet = new DatagramPacket(data,data.length,new InetSocketAddress("localhost",8888));
//4、发送
client.send(packet);
//5、释放
client.close();

}

/**
 * 字节数组 数据源  +Data 输出流
 * @param num
 * @return
 * @throws IOException 
 */
public static byte[] convert(double num) throws IOException{
byte[] data =null;
ByteArrayOutputStream bos = new ByteArrayOutputStream();
DataOutputStream dos =new DataOutputStream(bos);
dos.writeDouble(num);
dos.flush();

//获取数据
data = bos.toByteArray();
dos.close();
return data;

}
}
import java.io.ByteArrayInputStream;import java.io.DataInputStream;import java.io.IOException;import java.net.DatagramPacket;import java.net.DatagramSocket;/** * 服务端 * 1、创建服务端 +端口 * 2、准备接受容器 * 3、封装成 包 * 4、接受数据 * 5、分析数据 字节数组-->double * 6、释放 * @author Administrator * */public class Server {/** * @param args * @throws IOException  */public static void main(String[] args) throws IOException {//1、创建服务端 +端口DatagramSocket server = new DatagramSocket(8888);//2、准备接受容器byte[] container = new byte[1024];//3、封装成 包 DatagramPacket(byte[] buf, int length) DatagramPacket packet =new DatagramPacket(container, container.length) ;//4、接受数据server.receive(packet);//5、分析数据double data =convert(packet.getData());System.out.println(data);//6、释放server.close();}/** * 字节数组 +Data 输入流 * @param data * @return * @throws IOException  */public static double convert(byte[] data) throws IOException{DataInputStream dis =new DataInputStream(new ByteArrayInputStream(data));double num =dis.readDouble();dis.close();return num;}}


TCP编程  聊天室

Server.java

package com.bjsxt.net.tcp.chat.demo04;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;

/**
 * 创建服务器
 * 写出数据：输出流
 * 读取数据：输入流
 * @author Administrator
 *
 */
public class Server {
private List<MyChannel> all = new ArrayList<MyChannel>();
/**
 * @param args
 * @throws IOException 
 */
public static void main(String[] args) throws IOException {
new Server().start();

}

public void start() throws IOException{
ServerSocket server =new ServerSocket(9999);
while(true){
Socket client =server.accept();
MyChannel channel = new MyChannel(client);
all.add(channel);//统一管理
new Thread(channel).start(); //一条道路
}
}


/**
 * 一个客户端 一条道路
 * 1、输入流
 * 2、输出流
 * 3、接收数据
 * 4、发送数据
 * @author Administrator
 *
 */
private class MyChannel implements Runnable{
private DataInputStream dis ;
private DataOutputStream dos ;
private boolean isRunning =true;
private String name; 
public MyChannel(Socket client ) {
try {
dis = new DataInputStream(client.getInputStream());
dos = new DataOutputStream(client.getOutputStream());
this.name =dis.readUTF();
this.send("欢迎您进入聊天室");
sendOthers(this.name+"进入了聊天室",true);
} catch (IOException e) {
//e.printStackTrace();
CloseUtil.closeAll(dis,dos);
isRunning =false;
}
}
/**
 * 读取数据
 * @return
 */
private String receive(){
String msg ="";
try {
msg=dis.readUTF();
} catch (IOException e) {
//e.printStackTrace();
CloseUtil.closeAll(dis);
isRunning =false;
all.remove(this); //移除自身
}
return msg;
}

/**
 * 发送数据
 */
private void send(String msg){
if(null==msg ||msg.equals("")){
return ;
}
try {
dos.writeUTF(msg);
dos.flush();
} catch (IOException e) {
//e.printStackTrace();
CloseUtil.closeAll(dos);
isRunning =false;
all.remove(this); //移除自身
}
}

/**
 * 发送给其他客户端
 */
private void sendOthers(String msg,boolean sys){
//是否为私聊 约定
if(msg.startsWith("@")&& msg.indexOf(":")>-1 ){ //私聊
//获取name
String name =msg.substring(1,msg.indexOf(":"));
String content = msg.substring(msg.indexOf(":")+1);
for(MyChannel other:all){
if(other.name.equals(name)){
other.send(this.name+"对您悄悄地说:"+content);
}
}
}else{
//遍历容器
for(MyChannel other:all){
if(other ==this){
continue;
}
if(sys){ //系统信息
other.send("系统信息:"+msg);
}else{
//发送其他客户端
other.send(this.name+"对所有人说:"+msg);
}
}
}
}


@Override
public void run() {
while(isRunning){
sendOthers(receive(),false);
}
}
}


}



Send.java

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.Socket;

/**
 * 发送数据 线程
 * @author Administrator
 *
 */
public class Send implements Runnable{
//控制台输入流
private BufferedReader console;
//管道输出流
private DataOutputStream dos;
//控制线程
private boolean isRunning =true;
//名称
private String name;
public Send() {
console =new BufferedReader(new InputStreamReader(System.in));
}
public Send(Socket client,String name){
this();
try {
dos =new DataOutputStream(client.getOutputStream());
this.name =name;
send(this.name);
} catch (IOException e) {
//e.printStackTrace();
isRunning =false;
CloseUtil.closeAll(dos,console);

}
}
//1、从控制台接收数据
private String getMsgFromConsole(){
try {
return console.readLine();
} catch (IOException e) {
//e.printStackTrace();
}
return "";
}
/**
 * 1、从控制台接收数据
 * 2、发送数据
 */
public void send(String msg){
try {
if(null!=msg&& !msg.equals("")){
dos.writeUTF(msg);
dos.flush(); //强制刷新
}
} catch (IOException e) {
//e.printStackTrace();
isRunning =false;
CloseUtil.closeAll(dos,console);
}
}


@Override
public void run() {
//线程体
while(isRunning){
send(getMsgFromConsole());
}
}

}


receive.java

package com.bjsxt.net.tcp.chat.demo04;

import java.io.DataInputStream;
import java.io.IOException;
import java.net.Socket;

/**
 * 接收线程 
 * @author Administrator
 *
 */
public class Receive implements Runnable {
//输入流
private  DataInputStream dis ;
//线程标识
private boolean isRunning = true;
public Receive() {
}
public Receive(Socket client){
try {
dis = new DataInputStream(client.getInputStream());
} catch (IOException e) {
e.printStackTrace();
isRunning =false;
CloseUtil.closeAll(dis);
}
}
/**
 * 接收数据
 * @return
 */
public String  receive(){
String msg ="";
try {
msg=dis.readUTF();
} catch (IOException e) {
e.printStackTrace();
isRunning =false;
CloseUtil.closeAll(dis);
}
return msg;
}
@Override
public void run() {
//线程体
while(isRunning){
System.out.println(receive());
}
}
}


CloseUtil.java

import java.io.Closeable;

/**
 * 关闭流的方法
 * @author Administrator
 *
 */
public class CloseUtil {
public static void closeAll(Closeable... io){
for(Closeable temp:io){
try {
if (null != temp) {
temp.close();
}
} catch (Exception e) {
// TODO: handle exception
}
}
}
}


Client.java

package com.bjsxt.net.tcp.chat.demo04;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.Socket;
import java.net.UnknownHostException;

/**
 * 创建客户端: 发送数据+接收数据
 * 写出数据：输出流
 * 读取数据：输入流
 * 
    输入流 与输出流 在同一个线程内 应该 独立处理，彼此独立

    加入名称


 * 
 * 
 * 
 * @author Administrator
 *
 */
public class Client {

/**
 * @param args
 * @throws IOException 
 * @throws UnknownHostException 
 */
public static void main(String[] args) throws UnknownHostException, IOException {
System.out.println("请输入名称:");
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String name = br.readLine();
if(name.equals("")){
return;
}

Socket client = new Socket("localhost",9999);
new Thread(new Send(client,name)).start(); //一条路径
new Thread(new Receive(client)).start(); //一条路径

}

}



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