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
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[]){
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);
}
}
class Test{
public static void main(String args[]){
int arr [] = new int [10];
System.out.println("arr数组长度"+arr.length);
for(int i = 0;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
- 定位：分享 Android&Java知识点，有兴趣可以继续关注
閱讀更多 java高級面試 的文章
