Java에서 일반적으로 사용되는 디자인 패턴은 무엇입니까?

public class Singleton{
    private static Singleton singleton = new Singleton();
    private Singleton(){
    }
    public static Singleton getInstance(){
        return singleton;
    }
}

Singleton.getInstance().method();

public class Singleton {  
    /* 持有私有静态实例，防止被引用，此处赋值为null，目的是实现延迟加载 */  
    private static Singleton instance = null;  
  
    /* 私有构造方法，防止被实例化 */  
    private Singleton() {}  
  
    /* 1:懒汉式，静态工程方法，创建实例 */  
    public static Singleton getInstance() {  
        if (instance == null) {  
            instance = new Singleton();  
        }  
        return instance;  
    }  
protected void method() {  
        System.out.println("SingletonInner");  
    }
}

public class SingletonInner {  
    private static volatile SingletonInner sInst = null;  // <<< 这里添加了 volatile  
    /** 
     * 私有的构造函数 
     */  
    private SingletonInner() {}  
  
    public static SingletonInner getInstance() {  
        if (inst == null) {            synchronized (SingletonInner.class) {if (inst == null) {
                    sInst = new SingletonInner();
                }
            }
        }        return sInst;  
    }    protected void method() {  
        System.out.println("SingletonInner");  
    }  
}

public class SingletonInner {  
    /** 
     * 内部类实现单例模式 
     * 延迟加载，减少内存开销   
     */  
    private static class SingletonHolder {  
        private static SingletonInner instance = new SingletonInner();  
    }  
  
    /** 
     * 私有的构造函数 
     */  
    private SingletonInner() {}  
  
    public static SingletonInner getInstance() {  
        return SingletonHolder.instance;  
    }  
  
    protected void method() {  
        System.out.println("SingletonInner");  
    }  
}

public class Factory{ //getClass 产生Sample 一般可使用动态类装载装入类。
    public static Sample creator(int which){ 
        if (which==1)
            return new SampleA();
        else if (which==2)
            return new SampleB();
    }
}

Integer a=Integer.valueOf(100); //返回取值为100的Integer对象

public class Complex {
    private final float re;
    private final float im;

    private Complex(float re, float im){
        this.re = re;
        this.im = im;
    }

    public static Complex valueOf(float re, float im){
        return new Complex(re, im);
    }

    public static Complex valueOfPolar(float r, float theta){
        return new Complex((float)(r * Math.cos(theta)), (float)(r * Math.sin(theta)));
    }
}

Calendar cal=Calendar.getInstance(Locale.CHINA); //返回符合中国标准的日历

public class Director {
    private Builder builder;
    public Director( Builder builder ) {
        this.builder = builder;
　  }
　  // 将部件partA partB partC最后组成复杂对象
　  //这里是将车轮 方向盘和发动机组装成汽车的过程
    public void construct() {
        builder.buildPartA();
        builder.buildPartB();
        builder.buildPartC();
    }
}

public class ConcreteBuilder implements Builder {
　Part partA, partB, partC;
　public void buildPartA() {
　　//这里是具体如何构建　}
　public void buildPartB() {
　　//这里是具体如何构建　}
　public void buildPartC() {
　　//这里是具体如何构建　}
　public Product getResult() {
　　//返回最后组装成品结果　}
}

public interface Product { }

public interface Part { }

ConcreteBuilder builder = new ConcreteBuilder();
Director director = new Director( builder );
director.construct();
Product product = builder.getResult();

/**  
 * Subject(目标，Subject)：    
 * 目标知道它的观察者。可以有任意多个观察者观察同一个目标。  
 * 提供注册和删除观察者对象的接口。  
 */  public interface Subject {  
    public void attach(Observer mObserver);  
    public void detach(Observer mObserver);        
    public void notice();  
}

/**  
 * Observer(观察者，Observer)：  
 * 为那些在目标发生改变时需要获得通知的对象定义一个更新接口。   
 */  public interface Observer {  
    public void update();  
}

/**  
 * ConcreteSubject(具体目标，Teacher)  
 * 将有关状态存入各ConcreteObserve对象。  
 * 当他的状态发生改变时，向他的各个观察者发出通知。   
 */  public class Teacher implements Subject{  
     
    private String phone;  
    private Vector students;  
    
    public Teacher(){  
        phone = "";  
        students = new Vector();  
    }  
  
    @Override  
    public void attach(Observer mObserver) {  
        students.add(mObserver);  
    }  
  
    @Override  
    public void detach(Observer mObserver) {  
        students.remove(mObserver);  
    }  
  
    @Override  
    public void notice() {  
        for(int i=0;i<students.size();i++){  
            ((Observer)students.get(i)).update();  
        }  
    }  
  
    public String getPhone() {  
        return phone;  
    }  
  
    public void setPhone(String phone) {  
        this.phone = phone;  
        notice();  
    }  
}

/**  
 * ConcreteObserver(具体观察者, Student)：  
 * 维护一个指向ConcreteSubject对象的引用。  
 * 存储有关状态，这些状态应与目标的状态保持一致。  
 * 实现Observer的更新接口以使自身状态与目标的状态保持一致。  
 */  public class Student implements Observer{  
  
    private String name;  
    private String phone;  
    private Teacher mTeacher;  
      
    public Student(String name,Teacher t){  
       this.name = name;  
       mTeacher = t;  
    }  
      
    public void show(){  
       System.out.println("Name:"+name+"\nTeacher'sphone:" + phone);  
    }  
      
    @Override  
    public void update() {  
        phone = mTeacher.getPhone();  
    }  
}

/**  
 * 观察者(Observer)模式测试类   
 */  public class ObserverClient {  
    public static void main(String[] args) {  
       Vector students = new Vector();  
       Teacher t = new Teacher();  
       for(int i= 0;i<10;i++){  
           Student st = new Student("Andy.Chen"+i,t);  
           students.add(st);  
           t.attach(st);  
       }  
         
       System.out.println("Welcome to Andy.Chen Blog!" +"\n"   
                   +"Observer Patterns." +"\n"  
                   +"-------------------------------");  
         
       t.setPhone("12345678");  
       for(int i=0;i<3;i++)  
           ((Student)students.get(i)).show();  
         
       t.setPhone("87654321");  
       for(int i=0;i<3;i++)  
           ((Student)students.get(i)).show();  
    }  
}

Welcome to Andy.Chen Blog!  Observer Patterns.  
-------------------------------  Name:Andy.Chen0  
Teacher'sphone:12345678  
Name:Andy.Chen1  
Teacher'sphone:12345678  
Name:Andy.Chen2  
Teacher'sphone:12345678  
Name:Andy.Chen0  
Teacher'sphone:87654321  
Name:Andy.Chen1  
Teacher'sphone:87654321  
Name:Andy.Chen2  
Teacher'sphone:87654321

public interface Target {    /**
     * 这是源类Adaptee也有的方法     */
    public void sampleOperation1(); 
    /**
     * 这是源类Adapteee没有的方法     */
    public void sampleOperation2(); 
}public class Adaptee {    public void sampleOperation1(){}
}

public class Adapter {
    private Adaptee adaptee;
    public Adapter(Adaptee adaptee){
        this.adaptee = adaptee;
    }
    /**
     * 源类Adaptee有方法sampleOperation1
     * 因此适配器类直接委派即可
     */
    public void sampleOperation1(){
        this.adaptee.sampleOperation1();
    }
    /**
     * 源类Adaptee没有方法sampleOperation2
     * 因此由适配器类需要补充此方法
     */
    public void sampleOperation2(){
        //写相关的代码
    }
}

public class ForumPermissions implements Cacheable {
    /**
    * Permission to read object.
    */
    public static final int READ = 0;

    /**
    * Permission to administer the entire sytem.
    */
    public static final int SYSTEM_ADMIN = 1;

    /**
    * Permission to administer a particular forum.
    */
    public static final int FORUM_ADMIN = 2;

    /**
    * Permission to administer a particular user.
    */
    public static final int USER_ADMIN = 3;

    /**
    * Permission to administer a particular group.
    */
    public static final int GROUP_ADMIN = 4;

    /**
    * Permission to moderate threads.
    */
    public static final int MODERATE_THREADS = 5;

    /**
    * Permission to create a new thread.
    */
    public static final int CREATE_THREAD = 6;

    /**
    * Permission to create a new message.
    */
    public static final int CREATE_MESSAGE = 7;

    /**
    * Permission to moderate messages.
    */
    public static final int MODERATE_MESSAGES = 8;
  
    public boolean isSystemOrForumAdmin() {
        return (values[FORUM_ADMIN] || values[SYSTEM_ADMIN]);
    }

//相关操作代码
}

public class ForumProxy implements Forum {
    private ForumPermissions permissions;
    private Forum forum;
    this.authorization = authorization;

    public ForumProxy(Forum forum, Authorization authorization,ForumPermissions permissions){
        this.forum = forum;
        this.authorization = authorization;
        this.permissions = permissions;
    }
    .....
    public void setName(String name) throws UnauthorizedException,
        ForumAlreadyExistsException{
        //只有是系统或论坛管理者才可以修改名称
      if (permissions.isSystemOrForumAdmin()) {
        forum.setName(name);
      }
　　  else {
　　　 throw new UnauthorizedException();
　　  }
    }
    ...

}

public class DbForum implements Forum, Cacheable {
    ...
    public void setName(String name) throws ForumAlreadyExistsException {
　　....
        this.name = name;
　　     //这里真正将新名称保存到数据库中
　　     saveToDb();
　　....
    }
    ...
}

public interface Component {    
    void show();
}

public class Person implements Component{
    private String name;
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Person(String name){
        this.name = name;
    }

    @Override
    public void show() {
        System.out.println("装扮的" + name);
    }
}

public class Decorator implements Component{
    private Component mComponent;
    public void decoratorObj(Component component){
        mComponent = component;
    }

    @Override
    public void show() {
        if(mComponent != null){
            mComponent.show();
        }
    }
}

/** 牛仔裤 */
public class Jeans extends Decorator {
    @Override
    public void show(){
        System.out.println("穿牛仔裤");
        super.show();
    }
    
}

/**
 * Java에서 일반적으로 사용되는 디자인 패턴은 무엇입니까?测试客户端
 */
public class DecoratorClient {
    public static void main(String[] args) {
        System.out.println("Welcome to Andy.Chen Blog!" +"\n" 
                   +"Decorator Patterns." +"\n");
        
        Person mPerson = new Person("Andy");
        
        Sandal mSandal = new Sandal();
        Jeans mJeans = new Jeans();
        TShirt mShirt = new TShirt();
        
        mShirt.decoratorObj(mPerson);
        mJeans.decoratorObj(mShirt);
        mSandal.decoratorObj(mJeans);
        mSandal.show(); 
    }
}

Welcome to Andy.Chen Blog!
Decorator Patterns.
  
穿凉鞋
穿牛仔裤
穿T-Shirt
装扮的Andy