5个JAVA入门必看的经典实例

5个JAVA入门必看的经典实例

入门必看的5个java经典实例，供大家参考，具体内容如下

1.一个饲养员给动物喂食物的例子体现JAVA中的面向对象思想,接口（抽象类）的用处

package com.softeem.demo;

/**

*@author leno

*动物的接口

*/

interface Animal {

public void eat(Food food);

}

/**

*@author leno

*一种动物类:猫

*/

class Cat implements Animal {

public void eat(Food food) {

System.out.println("小猫吃" + food.getName());

}

}

/**

*@author leno

*一种动物类:狗

*/

class Dog implements Animal {

public void eat(Food food) {

System.out.println("小狗啃" + food.getName());

}

}

/**

*@author leno

*食物抽象类

*/

abstract class Food {

protected String name;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

}

/**

*@author leno

*一种食物类:鱼

*/

class Fish extends Food {

public Fish(String name) {

this.name = name;

}

}

/**

*@author leno

*一种食物类:骨头

*/

class Bone extends Food {

public Bone(String name) {

this.name = name;

}

}

/**

*@author leno

*饲养员类

*

*/

class Feeder {

/**

*饲养员给某种动物喂某种食物

*@param animal

*@param food

*/

public void feed(Animal animal, Food food) {

animal.eat(food);

}

}

/**

*@author leno

*测试饲养员给动物喂食物

*/

public class TestFeeder {

public static void main(String[] args) {

Feeder feeder = new Feeder();

Animal animal = new Dog();

Food food = new Bone("肉骨头");

feeder.feed(animal, food); //给狗喂肉骨头

animal = new Cat();

food = new Fish("鱼");

feeder.feed(animal, food); //给猫喂鱼

}

}

2.做一个单子模式的类，只加载一次属性文件

package com.softeem.demo;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStream;

import java.util.Properties;

/**

* @authorleno 单子模式，保证在整个应用期间只加载一次配置属性文件

*/

public class Singleton {

private static Singleton instance;

private static final String CONFIG_FILE_PATH = "E:\\config.properties";

private Properties config;

private Singleton() {

config = new Properties();

InputStream is;

try {

is = new FileInputStream(CONFIG_FILE_PATH);

config.load(is);

is.close();

} catch (FileNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

public static Singleton getInstance() {

if (instance == null) {

instance = new Singleton();

}

retTJrHIklGfurn instance;

}

public Properties getConfig() {

return config;

}

public void setConfig(Properties config) {

this.config = config;

}

}

3.用JAVA中的多线程示例银行取款问题

package com.softeem.demo;

/**

*@author leno

*账户类

*默认有余额，可以取款

*/

class Account {

private float balance = 1000;

public float getBalance() {

return balance;

}

public void setBalance(float balance) {

this.balance = balance;

}

/**

*取款的方法需要同步

*@param money

*/

public synchronized void withdrawals(float money) {

if (balance >= money) {

System.out.println("被取走" + money + "元!");

try {

Thread.sleep(1000);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

balance -= money;

} else {

System.out.println("对不起,余额不足!");

}

}

}

/**

*@author leno

*银行卡

*/

class TestAccount1 extends Thread {

private Account account;

public TestAccount1(Account account) {

this.account = account;

}

@Override

public void run() {

account.withdrawals(800);

System.out.println("余额为:" + account.getBalance() + "元!");

}

}

/**

*@authorleno

*存折

*/

class TestAccount2 extends Thread {

private Account account;

public TestAccount2(Account account) {

this.account = account;

}

@Override

public void run() {

account.withdrawals(700);

System.out.println("余额为:" + account.getBalance() + "元!");

}

}

public class Test {

public static void main(String[] args) {

Account account = new Account();

TestAccount1 testAccount1 = new TestAccount1(account);

testAccount1.start();

TestAccount2 testAccount2 = new TestAccount2(account);

testAccount2.start();

}

}

4.用JAVA中的多线程示例生产者和消费者问题

package com.softeem.demo;

class Producer implements Runnable {

private SyncStack stack;

public Producer(SyncStack stack) {

this.stack = stack;

}

public void run() {

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

String product = "产品" + i;

stack.push(product);

System.out.println("生产了: " + product);

try {

Thread.sleep(200);

} catch (InterruptedException e) {

e.printStackTrace();

}

}

}

}

class Consumer implements Runnable {

private SyncStack stack;

public Consumer(SyncStack stack) {

this.stack = stack;

}

public void run() {

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

String product = stack.pop();

System.out.println("消费了: " + product);

try {

Thread.sleep(1000);

} catch (InterruptedException e) {

e.printStackTrace();

}

}

}

}

class SyncStack {

private String[] products = new String[10];

private int index;

public synchronized void push(String product) {

if (index == product.length()) {

try {

wait();

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

notify();

products[index] = product;

index++;

}

public synchronized String pop() {

if (index == 0) {

http://try {

wait();

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

notify();

index--;

String product = products[index];

return product;

}

public String[] getProducts() {

return products;

}

}

public class TestProducerConsumer {

public static void main(String[] args) {

SyncStack stack = new SyncStack();

Producer p = new Producer(stack);

Consumer c = new Consumer(stack);

new Thread(p).start();

new Thread(c).start();

}

}

5.编程实现序列化的Student（sno,sname）对象在网络上的传输

package com.softeem.demo;

import java.io.IOException;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import java.io.Serializable;

import java.net.ServerSocket;

import java.net.Socket;

class Student implements Serializable {

private int sno;

private String sname;

public Student(int sno, String sname) {

this.sno = sno;

this.sname = sname;

}

public int getSno() {

return sno;

}

public void setSno(int sno) {

this.sno = sno;

}

public String getSname() {

return sname;

}

public void setSname(String sname) {

this.sname = sname;

}

@Override

public String toString() {

return "学号:" + sno + ";姓名:" + sname;

}

}

class MyClient extends Thread {

@Override

public void run() {

try {

Socket s = new Socket("localhost", 9999);

ObjectInputStream ois = new ObjectInputStream(s.getInputStream());

Student stu = (Student) ois.readObject();

String msg = "客户端程序收到服务器端程序传输过来的学生对象>> " + stu;

System.out.println(msg);

ois.close();

s.close();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

class MyServer extends Thread {

@Override

public void run() {

try {

ServerSocket ss = new ServerSocket(9999);

Socket s = ss.accept();

ObjectOutputStream ops = new ObjectOutputStream(s.getOutputStream());

Student stu = new Student(1, "赵本山");

ops.writeObject(stu);

ops.close();

s.close();

ss.close();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

public class TestTransfer {

public static void main(String[] args) {

new MyServer().start();

new MyClient().start();

}

}

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