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工厂模式 就是用对象不要自己new 了,要先创建其对象的工厂,DateFormat就是,getDateInstance是得到该对象的一个实例(就是得到你想要的对象),然后就可以继续使用对象的方法做事了
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package TestObserver;
import java.util.Iterator;
import java.util.Vector;
/**
*
* @author Seastar
*/
interface Observed {
public void addObserver(Observer o);
public void removeObserver(Observer o);
public void update();
}
interface Observer {
public void takeAction();
}
class Invoker {
private Observer o;
Handler handler;
public Invoker(Observer o) {
new Handler();
this.o = o;
}
private class Handler extends Thread {
public Handler() {
handler = this;
}
@Override
public void run() {
o.takeAction();
}
}
public boolean TestSameObserver(Observer o) {
return o == this.o;
}
public void invoke() {
handler.start();
}
}
class ObservedObject implements Observed {
private VectorInvoker observerList = new VectorInvoker();
public void addObserver(Observer o) {
observerList.add(new Invoker(o));
}
public void removeObserver(Observer o) {
IteratorInvoker it = observerList.iterator();
while (it.hasNext()) {
Invoker i = it.next();
if (i.TestSameObserver(o)) {
observerList.remove(i);
break;
}
}
}
public void update() {
for (Invoker i : observerList) {
i.invoke();
}
}
}
class ObserverA implements Observer {
public void takeAction() {
System.out.println("I am Observer A ,state changed ,so i have to do something");
}
}
class ObserverB implements Observer {
public void takeAction() {
System.out.println("I am Observer B ,i was told to do something");
}
}
class ObserverC implements Observer {
public void takeAction() {
System.out.println("I am Observer C ,I just look ,and do nothing");
}
}
public class Main {
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
ObserverA a = new ObserverA();
ObserverB b = new ObserverB();
ObserverC c = new ObserverC();
ObservedObject oo = new ObservedObject();
oo.addObserver(a);
oo.addObserver(b);
oo.addObserver(c);
for (int i = 0; i 5; ++i) {
oo.addObserver(new Observer() {
public void takeAction() {
System.out.println("我是山寨观察者"+",谁敢拦我");
}
});
}
//sometime oo changed ,so it calls update and informs all observer
oo.update();
}
}
观察者模式的精髓在于注册一个观察者观测可能随时变化的对象,对象变化时就会自动通知观察者,
这样在被观测对象影响范围广,可能引起多个类的行为改变时很好用,因为无需修改被观测对象的代码就可以增加被观测对象影响的类,这样的设计模式使得代码易于管理和维护,并且减少了出错几率
至于异步机制实际是个噱头,可以有观测对象来实现异步,也可以有观察者自身实现,这个程序实际是观测对象实现了异步机制,方法是在观察者类外包装了一层invoker类
共四个java文件,源代码如下:
import java.awt.*;
import java点虐 .*;
import java.awt.event.*;
import java.io.*;
import java.util.Hashtable;
public class ChatArea extends Panel implements ActionListener,Runnable
{
Socket socket=null;
DataInputStream in=null;
DataOutputStream out=null;
Thread threadMessage=null;
TextArea 谈话显示区,私聊显示区=null;
TextField 送出信息=null;
Button 确定,刷新谈话区,刷新私聊区;
Label 提示条=null;
String name=null;
Hashtable listTable;
List listComponent=null;
Choice privateChatList;
int width,height;
public ChatArea(String name,Hashtable listTable,int width,int height)
{
setLayout(null);
setBackground(Color.orange);
this.width=width;
this.height=height;
setSize(width,height);
this.listTable=listTable;
this.name=name;
threadMessage=new Thread(this);
谈话显示区=new TextArea(10,10);
私聊显示区=new TextArea(10,10);
确定=new Button("送出信息到:");
刷新谈话区=new Button("刷新谈话区");
刷新私聊区=new Button("刷新私聊区");
提示条=new Label("双击聊天者可私聊",Label.CENTER);
送出信息=new TextField(28);
确定.addActionListener(this);
送出信息.addActionListener(this);
刷新谈话区.addActionListener(this);
刷新私聊区.addActionListener(this);
listComponent=new List();
listComponent.addActionListener(this);
privateChatList=new Choice();
privateChatList.add("大家(*)");
privateChatList.select(0);
add(谈话显示区);
谈话显示区.setBounds(10,10,(width-120)/2,(height-120));
add(私聊显示区);
私聊显示区.setBounds(10+(width-120)/2,10,(width-120)/2,(height-120));
add(listComponent);
listComponent.setBounds(10+(width-120),10,100,(height-160));
add(提示条);
提示条.setBounds(10+(width-120),10+(height-160),110,40);
Panel pSouth=new Panel();
pSouth.add(送出信息);
pSouth.add(确定);
pSouth.add(privateChatList);
pSouth.add(刷新谈话区);
pSouth.add(刷新私聊区);
add(pSouth);
pSouth.setBounds(10,20+(height-120),width-20,60);
}
public void setName(String s)
{
name=s;
}
public void setSocketConnection(Socket socket,DataInputStream in,DataOutputStream out)
{
this.socket=socket;
this.in=in;
this.out=out;
try
{
threadMessage.start();
}
catch(Exception e)
{
}
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==确定||e.getSource()==送出信息)
{
String message="";
String people=privateChatList.getSelectedItem();
people=people.substring(0,people.indexOf("("));
message=送出信息.getText();
if(message.length()0)
{
try {
if(people.equals("大家"))
{
out.writeUTF("公共聊天内容:"+name+"说:"+message);
}
else
{
out.writeUTF("私人聊天内容:"+name+"悄悄地说:"+message+"#"+people);
}
}
catch(IOException event)
{
}
}
}
else if(e.getSource()==listComponent)
{
privateChatList.insert(listComponent.getSelectedItem(),0);
privateChatList.repaint();
}
else if(e.getSource()==刷新谈话区)
{
谈话显示区.setText(null);
}
else if(e.getSource()==刷新私聊区)
{
私聊显示区.setText(null);
}
}
public void run()
{
while(true)
{
String s=null;
try
{
s=in.readUTF();
if(s.startsWith("聊天内容:"))
{
String content=s.substring(s.indexOf(":")+1);
谈话显示区.append("\n"+content);
}
if(s.startsWith("私人聊天内容:"))
{
String content=s.substring(s.indexOf(":")+1);
私聊显示区.append("\n"+content);
}
else if(s.startsWith("聊天者:"))
{
String people=s.substring(s.indexOf(":")+1,s.indexOf("性别"));
String sex=s.substring(s.indexOf("性别")+2);
listTable.put(people,people+"("+sex+")");
listComponent.add((String)listTable.get(people));
listComponent.repaint();
}
else if(s.startsWith("用户离线:"))
{
String awayPeopleName=s.substring(s.indexOf(":")+1);
listComponent.remove((String)listTable.get(awayPeopleName));
listComponent.repaint();
谈话显示区.append("\n"+(String)listTable.get(awayPeopleName)+"离线");
listTable.remove(awayPeopleName);
}
Thread.sleep(5);
}
catch(IOException e)
{
listComponent.removeAll();
listComponent.repaint();
listTable.clear();
谈话显示区.setText("和服务器的连接已中断\n必须刷新浏览器才能再次聊天");
break;
}
catch(InterruptedException e)
{
}
}
}
}
ChatServer.java
import java.io.*;
import java点虐 .*;
import java.util.*;
public class ChatServer
{
public static void main(String args[])
{
ServerSocket server=null;
Socket you=null;
Hashtable peopleList;
peopleList=new Hashtable();
while(true)
{
try
{
server=new ServerSocket(6666);
}
catch(IOException e1)
{
System.out.println("正在监听");
}
try {
you=server.accept();
InetAddress address=you.getInetAddress();
System.out.println("用户的IP:"+address);
}
catch (IOException e)
{
}
if(you!=null)
{
Server_thread peopleThread=new Server_thread(you,peopleList);
peopleThread.start();
}
else {
continue;
}
}
}
}
class Server_thread extends Thread
{
String name=null,sex=null;
Socket socket=null;
File file=null;
DataOutputStream out=null;
DataInputStream in=null;
Hashtable peopleList=null;
Server_thread(Socket t,Hashtable list)
{
peopleList=list;
socket=t;
try {
in=new DataInputStream(socket.getInputStream());
out=new DataOutputStream(socket.getOutputStream());
}
catch (IOException e)
{
}
}
public void run()
{
while(true)
{ String s=null;
try
{
s=in.readUTF();
if(s.startsWith("姓名:"))
{
name=s.substring(s.indexOf(":")+1,s.indexOf("性别"));
sex=s.substring(s.lastIndexOf(":")+1);
boolean boo=peopleList.containsKey(name);
if(boo==false)
{
peopleList.put(name,this);
out.writeUTF("可以聊天:");
Enumeration enum=peopleList.elements();
while(enum.hasMoreElements())
{
Server_thread th=(Server_thread)enum.nextElement();
th.out.writeUTF("聊天者:"+name+"性别"+sex);
if(th!=this)
{
out.writeUTF("聊天者:"+th.name+"性别"+th.sex);
}
}
}
else
{
out.writeUTF("不可以聊天:");
}
}
else if(s.startsWith("公共聊天内容:"))
{
String message=s.substring(s.indexOf(":")+1);
Enumeration enum=peopleList.elements();
while(enum.hasMoreElements())
{
((Server_thread)enum.nextElement()).out.writeUTF("聊天内容:"+message);
}
}
else if(s.startsWith("用户离开:"))
{
Enumeration enum=peopleList.elements();
while(enum.hasMoreElements())
{ try
{
Server_thread th=(Server_thread)enum.nextElement();
if(th!=thisth.isAlive())
{
th.out.writeUTF("用户离线:"+name);
}
}
catch(IOException eee)
{
}
}
peopleList.remove(name);
socket.close();
System.out.println(name+"用户离开了");
break;
}
else if(s.startsWith("私人聊天内容:"))
{
String 悄悄话=s.substring(s.indexOf(":")+1,s.indexOf("#"));
String toPeople=s.substring(s.indexOf("#")+1);
Server_thread toThread=(Server_thread)peopleList.get(toPeople);
if(toThread!=null)
{
toThread.out.writeUTF("私人聊天内容:"+悄悄话);
}
else
{
out.writeUTF("私人聊天内容:"+toPeople+"已经离线");
}
}
}
catch(IOException ee)
{
Enumeration enum=peopleList.elements();
while(enum.hasMoreElements())
{ try
{
Server_thread th=(Server_thread)enum.nextElement();
if(th!=thisth.isAlive())
{
th.out.writeUTF("用户离线:"+name);
}
}
catch(IOException eee)
{
}
}
peopleList.remove(name);
try
{
socket.close();
}
catch(IOException eee)
{
}
System.out.println(name+"用户离开了");
break;
}
}
}
}
import java.awt.*;
import java.io.*;
import java点虐 .*;
import java.applet.*;
import java.util.Hashtable;
ClientChat.java
public class ClientChat extends Applet implements Runnable
{
Socket socket=null;
DataInputStream in=null;
DataOutputStream out=null;
InputNameTextField 用户提交昵称界面=null;
ChatArea 用户聊天界面=null;
Hashtable listTable;
Label 提示条;
Panel north, center;
Thread thread;
public void init()
{
int width=getSize().width;
int height=getSize().height;
listTable=new Hashtable();
setLayout(new BorderLayout());
用户提交昵称界面=new InputNameTextField(listTable);
int h=用户提交昵称界面.getSize().height;
用户聊天界面=new ChatArea("",listTable,width,height-(h+5));
用户聊天界面.setVisible(false);
提示条=new Label("正在连接到服务器,请稍等...",Label.CENTER);
提示条.setForeground(Color.red);
north=new Panel(new FlowLayout(FlowLayout.LEFT));
center=new Panel();
north.add(用户提交昵称界面);
north.add(提示条);
center.add(用户聊天界面);
add(north,BorderLayout.NORTH);
add(center,BorderLayout.CENTER);
validate();
}
public void start()
{
if(socket!=nullin!=nullout!=null)
{ try
{
socket.close();
in.close();
out.close();
用户聊天界面.setVisible(false);
}
catch(Exception ee)
{
}
}
try
{
socket = new Socket(this.getCodeBase().getHost(), 6666);
in=new DataInputStream(socket.getInputStream());
out=new DataOutputStream(socket.getOutputStream());
}
catch (IOException ee)
{
提示条.setText("连接失败");
}
if(socket!=null)
{
InetAddress address=socket.getInetAddress();
提示条.setText("连接:"+address+"成功");
用户提交昵称界面.setSocketConnection(socket,in,out);
north.validate();
}
if(thread==null)
{
thread=new Thread(this);
thread.start();
}
}
public void stop()
{
try
{
socket.close();
thread=null;
}
catch(IOException e)
{
this.showStatus(e.toString());
}
}
public void run()
{
while(thread!=null)
{
if(用户提交昵称界面.get能否聊天()==true)
{
用户聊天界面.setVisible(true);
用户聊天界面.setName(用户提交昵称界面.getName());
用户聊天界面.setSocketConnection(socket,in,out);
提示条.setText("祝聊天愉快!");
center.validate();
break;
}
try
{
Thread.sleep(100);
}
catch(Exception e)
{
}
}
}
}
InputNameTextField。java
import java.awt.*;
import java点虐 .*;
import java.awt.event.*;
import java.io.*;
import java.util.Hashtable;
public class InputNameTextField extends Panel implements ActionListener,Runnable
{
TextField nameFile=null;
String name=null;
Checkbox male=null,female=null;
CheckboxGroup group=null;
Button 进入聊天室=null,退出聊天室=null;
Socket socket=null;
DataInputStream in=null;
DataOutputStream out=null;
Thread thread=null;
boolean 能否聊天=false;
Hashtable listTable;
public InputNameTextField(Hashtable listTable)
{
this.listTable=listTable;
nameFile=new TextField(10);
group=new CheckboxGroup();
male=new Checkbox("男",true,group);
female=new Checkbox("女",false,group);
进入聊天室=new Button("进入");
退出聊天室=new Button("退出");
进入聊天室.addActionListener(this);
退出聊天室.addActionListener(this);
thread=new Thread(this);
add(new Label("昵称:"));
add(nameFile);
add(male);
add(female);
add(进入聊天室);
add(退出聊天室);
退出聊天室.setEnabled(false);
}
public void set能否聊天(boolean b)
{
能否聊天=b;
}
public boolean get能否聊天()
{
return 能否聊天;
}
public String getName()
{
return name;
}
public void setName(String s)
{
name=s;
}
public void setSocketConnection(Socket socket,DataInputStream in,DataOutputStream out)
{
this.socket=socket;
this.in=in;
this.out=out;
try{
thread.start();
}
catch(Exception e)
{
nameFile.setText(""+e);
}
}
public Socket getSocket()
{
return socket;
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==进入聊天室)
{
退出聊天室.setEnabled(true);
if(能否聊天==true)
{
nameFile.setText("您正在聊天:"+name);
}
else
{
this.setName(nameFile.getText());
String sex=group.getSelectedCheckbox().getLabel();
if(socket!=nullname!=null)
{
try{
out.writeUTF("姓名:"+name+"性别:"+sex);
}
catch(IOException ee)
{
nameFile.setText("没有连通服务器"+ee);
}
}
}
}
if(e.getSource()==退出聊天室)
{
try
{
out.writeUTF("用户离开:");
}
catch(IOException ee)
{
}
}
}
public void run()
{
String message=null;
while(true)
{
if(in!=null)
{
try
{
message=in.readUTF();
}
catch(IOException e)
{
nameFile.setText("和服务器断开"+e);
}
}
if(message.startsWith("可以聊天:"))
{
能否聊天=true;
break;
}
else if(message.startsWith("聊天者:"))
{
String people=message.substring(message.indexOf(":")+1);
listTable.put(people,people);
}
else if(message.startsWith("不可以聊天:"))
{
能否聊天=false;
nameFile.setText("该昵称已被占用");
}
}
}
}
我们在微信上24小时期待你的声音
解答本文疑问/技术咨询/运营咨询/技术建议/互联网交流