前言

大家好，给大家带来详细讲解Java中的泛型，多线程，网络编程的概述，希望你们喜欢

泛型

泛型格式：ArrayList list= new ArrayList();

ArrayList list= new ArrayList<>();

Type可以为类，接口

使用泛型可以使加入的，不用被强制

通配符

ArrayList<? extends Type> list= new ArrayList<>();

代表任意泛型

多线程

在同一时间,做多件事情.

创建线程的方法

继承类Thread并重写run()，run()称为线程体；用这种方法定义的类不能再继承其他类。

class FirstThread extends Thread{

public void run(){

 for(int i=0;i<100;i++){

  System.out.println("FirstThread"+i);

 }

}

}

class Test{

public static void main(Sting args[]){

 FirstThread ft = new FirstThread();

 ft.start();

 for(int i = 0; i<100;i++){

  System.out.println("main"+i):

 }

}

}

接口Runnable的类作为线程的目标对象

class Test implements Runnable{

public void run(){

 for(int i = 0;i<100;i++){

  System.out.println("Runnable"+i);

 }

}

}

class Test{

public static void main(String args[]){

 Test test = new Test();

 Thread t = new Thread(test);

 System.out.println(t.getPriority());

 t.start();

}

}

中断线程

Thread.sleep();

Thread.yield();//让出自己正在使用的CPU

设置线程的优先级

getPriority();

setPriority();

class Test implements Runnable{

public void run(){

 for(int i = 0;i<100;i++){

  System.out.println("Runnable"+i);

  if(i==50){

   try{

    Thread.sleep(2000);

   }

   catch(Exception e){

    System.out.println(e);

   }

  }

 }

}

}

class Test{

public static void main(String args[]){

 RunnableImp1 ri = new RunnableImp1();

 Thread t = new Thread(ri);

 t.setPriority(Thread.MAX_PRIORITY);

 //t.setPriority(Thread.MIN_PRIORITY);

 t.start();

 System.out.println(t.getPriority());

 }

}

class Test{

public static void main(String args[]){

 MyThread myThread = new MyThread();

 Thread t1 = new Thread(myThread);

 Thread t2 = new Thread(myThread);

 t1.setName("线程1");

 t2.setName("线程2");

 //分别启动

 t1.start();

 t2.start();

}

}

class MyThread implements Runnable{

int i = 100;

public void run(){

 while(true){

  System.out.println(Thread.currentThread().getName()+i);

  i--;

  Thread.yield();

  if(i<0){

   break;

  }

 }

}

}

//同步代码块

class MyThread implements Runnable{

int i = 100;

public void run(){

 while(true){

  synchronized(this){

   System.out.println(Thread.currentThread().getName()+i);

   i--;

   Thread.yield();

   if(i<0){

    break;

   }

  }

 }

}

}

深入synchronized关键字

class Service{

public void fun1(){

 synchronized(this){

  try{

   Thread.sleep(3*1000);

  }

  catch(Exception e){

   System.out.println("fun1");

  }

 }

public void fun2(){

 synchronized(this){

  System.out.println("fun2");

 }

}

}

class MyThread1 implements Runnable{

private Service service;

public MyThread1(Service service){

 this.service = service;

}

public void run(){

 service.fun1();

}

}

class MyThread2 implements Runable{

private Service service;

public MyThread2(Service service){

 this.service = service;

}

public void run(){

 service.fun2();

}

}

class Test{

public static void main(String args[]){

 Service service = new Service();

 Thread t1=new Thread(new MyThread1(service));

 Thread t2=new Thread(new MyThread2(service));

 t1.start();

 t2.start();

}

}

同步锁 锁住的是service

同步方法，同步代码块锁住this

class Service{

public synchronized void fun1(){

 try{

  Thread.sleep(3*1000);

 }

 catch(Exception e){

  System.out.println(e);

 }

 System.out.println("fun1");

}

public void fun2(){

 synchronized(this){

  System.out.println("fun2");

}

}

}

数组

class Test{

public static void main(String args[]){

 //数组的静态声明

 int arr [] = {5,2,7,8,9,0};

 arr[3] = 10;

 //System.out.println(arr[3]);

 for(int i = 0;i<5;i++){

   System.out.println(arr[i]);

  }

 }

}

class Test{

public static void main(String args[]){

 int arr[] = {2,4,6,7,8};

 System.out.println(arr.length);

 }

}

数组的动态声明

class Test{

public static void main(String args[]){

//动态声明

int arr [] = new int [10];

System.out.println("arr数组长度"+arr.length);

  for(int i = 0;i<arr.length;i++){

   System.out.println(arr[i]);

  }

}

}

二维数组

class Test{

public static void main(String args[]){

 //二维数组的定义方法，长度为3

  int arr [][] = {{1,2,3},{4,5,6},{7,8,9}}；

  System.out.println(arr[1][1]);

  for(int i = 0; i < 3; i++){

   for(int j = 0; j < 3; j++){

    System.out.println(arr[i][j]);

   }

  }

}

}

优化

class Test{

public static void main(String args[]){

 //二维数组的定义方法，长度为3

  int arr [][] = {{1,2,3},{4,5,6},{7,8}}；

  System.out.println(arr[1][1]);

  for(int i = 0; i < arr.length; i++){

   for(int j = 0; j < arr[i].length; j++){

    System.out.println(arr[i][j]);

   }

  }

}

}

动态

class Test{

public static void main(String args[]){

  //int arr [][] = {{1,2,3},{4,5,6},{7,8}}；

  int arr [][] = new int[3][5]; 

  System.out.println(arr[1][1]);

  for(int i = 0; i < arr.length; i++){

   for(int j = 0; j < arr[i].length; j++){

    System.out.println(arr[i][j]);

   }

  }

}

}

线程概念

进程：就是执行一个任务；

线程：就是在进程内部同时做的事情。

网络开发Socket和ServerSocket

Socket为“孔”或“插座”，创建Socket，打开连接Socket的输入或输出流，对Socket进行读写，关闭Socket。

Accept方法用于产生“阻塞”，这里有getInputStream方法和getOutInputStream方法，会产生一个IOException，

在Java.net包中，有Socket和ServerSocket两个类。以JDK1.6介绍：

public Socket()

public Socket(String host, int port)

//host - 主机名，或者为 null，表示回送地址

//port - 端口号

public Socket(InetAddress address,int port)

//address - IP 地址

//port - 端口号

ServerSocket(int port)

ServerSocket(int port,int backlog)

ServerSocket(int port,int backlog,InetAddress binAddr)

服务器与客户端通信

package two;

import java.io.DataInputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.PrintStream;

import java.net.ServerSocket;

import java.net.Socket;

public class ServerSocket1 {

 public static void main(String[] args) {

   // TODO Auto-generated method stub

   try {

     ServerSocket ss = new ServerSocket(2007);

     while(true) {

       Socket s = ss.accept();

       InputStream is = s.getInputStream();

       OutputStream os = s.getOutputStream();

       PrintStream ps = new PrintStream(os);

       ps.println("helloworld, i am server thinkpad");

       DataInputStream dis = new DataInputStream(is);

       String str = dis.readLine();

       System.out.println(str);

       s.close();

     }

   }

   catch(IOException ee) {

     System.out.println(ee);

   }

   catch(Exception e) {

     System.out.println(e);

   }

 }

}

package two;

import java.io.DataInputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.PrintStream;

import java.net.ConnectException;

import java.net.Socket;

public class ClientSocket {

 public static void main(String[] args) {

   // TODO Auto-generated method stub

   try {

     Socket s = new Socket("########",2007);

     InputStream is = s.getInputStream();

     OutputStream os = s.getOutputStream();

     PrintStream ps = new PrintStream(os);

     ps.println("hello , i am client");

     DataInputStream dis = new DataInputStream(is);

     String str = dis.readLine();

     System.out.println(str);

     s.close();

   }

   catch(ConnectException eee) {

     System.out.println(eee);

   }

   catch(IOException ee) {

     System.out.println(ee);

   }

   catch(Exception e) {

     System.out.println(e);

   }

 }

}

总结

• 本文讲了详细讲解Java中的泛型，多线程，网络编程，如果您还有更好地理解，欢迎沟通
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