Java工廠模式是一種創(chuàng)建型設(shè)計模式，它定義了一個用于創(chuàng)建對象的接口，但是讓子類來決定實例化哪個類。其實現(xiàn)思路是將所要創(chuàng)建的對象放在一個工廠類中，由工廠類負責(zé)生產(chǎn)實例，這樣一來，客戶端只需要知道工廠類的接口就可以獲得所需的對象，而不需要知道具體的實現(xiàn)細節(jié)。

public interface Shape {
void draw();
}
public class Rectangle implements Shape {
@Override
public void draw() {
System.out.println("Inside Rectangle::draw() method.");
}
}
public class Square implements Shape {
@Override
public void draw() {
System.out.println("Inside Square::draw() method.");
}
}
public class ShapeFactory {
public Shape getShape(String shapeType){
if(shapeType == null){
return null;
}     
if(shapeType.equalsIgnoreCase("CIRCLE")){
return new Circle();
}else if(shapeType.equalsIgnoreCase("RECTANGLE")){
return new Rectangle();
}else if(shapeType.equalsIgnoreCase("SQUARE")){
return new Square();
}
return null;
}
}
public class FactoryPatternDemo {
public static void main(String[] args) {
ShapeFactory shapeFactory = new ShapeFactory();
//獲取形狀為圓形的對象
Shape shape1 = shapeFactory.getShape("CIRCLE");
//調(diào)用Circle的draw方法
shape1.draw();
//獲取形狀為長方形的對象
Shape shape2 = shapeFactory.getShape("RECTANGLE");
//調(diào)用Rectangle的draw方法
shape2.draw();
//獲取形狀為正方形的對象
Shape shape3 = shapeFactory.getShape("SQUARE");
//調(diào)用Square的draw方法
shape3.draw();
}
}

Java代理模式是一種結(jié)構(gòu)型設(shè)計模式，它允許對象在不暴露自己的情況下，控制其它對象的訪問。代理可以對請求進行過濾和轉(zhuǎn)發(fā)，以及在訪問對象時添加必要的附加操作。代理模式通常用于提供對對象的訪問控制，于是即使用戶沒權(quán)限訪問對象也可在代理對象中控制用戶對該對象的訪問。

public interface Image {
void display();
}
public class RealImage implements Image {
private String fileName;
public RealImage(String fileName){
this.fileName = fileName;
loadFromDisk(fileName);
}
@Override
public void display() {
System.out.println("Displaying " + fileName);
}
private void loadFromDisk(String fileName){
System.out.println("Loading " + fileName);
}
}
public class ProxyImage implements Image{
private RealImage realImage;
private String fileName;
public ProxyImage(String fileName){
this.fileName = fileName;
}
@Override
public void display() {
if(realImage == null){
realImage = new RealImage(fileName);
}
realImage.display();
}
}
public class ProxyPatternDemo {
public static void main(String[] args) {
Image image = new ProxyImage("test.jpg");
//圖像從磁盤加載
image.display();
//圖像不需要從磁盤加載
image.display(); 
}
}