建造者模式是一种创建型设计模式，旨在将复杂的对象构建过程与其表示分离，从而使构建过程更加灵活和可扩展。本文将详细讨论建造者模式的概念、结构、应用场景和实现方法 。，，建造者模式的优点包括：1. 可以降低客户端与抽象建造者的耦合度；2. 可以提高代码的可读性和可维护性；3. 可以提高代码的复用性；4. 可以提高代码的扩展性 。
在编程领域，设计模式是一种被广泛应用的解决方案，它们可以帮助我们解决一些常见的问题，我们将重点讨论一种被称为“建造者模式”的设计模式，建造者模式是一种创建型设计模式，它提供了一种在不指定具体类的情况下创建对象的方法，这种模式的主要目标是将一个复杂对象的构建与其表示分离，使得同样的构建过程可以创建不同的表示。
让我们来了解一下建造者模式的基本概念，建造者模式包含三个角色：抽象建造者(Builder)、具体建造者(ConcreteBuilder)和指挥者(Director)，抽象建造者定义了创建产品对象的行为，但不包含具体的实现；具体建造者实现了抽象建造者所定义的行为，并负责创建产品对象；指挥者则负责协调各个部分的工作，调用具体建造者的创建方法。
下面我们通过一个简单的例子来说明如何使用建造者模式，假设我们要创建一个电脑类(Computer),它有一个显示器(Monitor)和一个键盘(Keyboard)作为组成部分，我们可以使用建造者模式来实现这个类的创建过程。
1、我们需要定义抽象建造者接口(ComputerBuilder):
public interface ComputerBuilder {
void buildMonitor();
void buildKeyboard();
Computer build();
}2、我们需要定义具体建造者类(MonitorBuilder和KeyboardBuilder):
public class MonitorBuilder implements ComputerBuilder {
private int size;
public MonitorBuilder(int size) {
this.size = size;
}
@Override
public void buildMonitor() {
System.out.println("Building monitor with size: " + size);
}
@Override
public void buildKeyboard() {
// Do nothing
}
@Override
public Computer build() {
return new Monitor(size);
}
}
public class KeyboardBuilder implements ComputerBuilder {
private String type;
public KeyboardBuilder(String type) {
this.type = type;
}
@Override
public void buildMonitor() {
// Do nothing
}
@Override
public void buildKeyboard() {
System.out.println("Building keyboard with type: " + type);
}
@Override
public Computer build() {
return new Keyboard(type);
}
}3、我们需要定义指挥者类(ComputerDirector):
public class ComputerDirector implements ComputerBuilder {
private MonitorBuilder monitorBuilder;
private KeyboardBuilder keyboardBuilder;
public ComputerDirector(MonitorBuilder monitorBuilder, KeyboardBuilder keyboardBuilder) {
this.monitorBuilder = monitorBuilder;
this.keyboardBuilder = keyboardBuilder;
}
@Override
public void buildMonitor() {
monitorBuilder.buildMonitor();
}
@Override
public void buildKeyboard() {
keyboardBuilder.buildKeyboard();
}
@Override
public Computer build() throws Exception {
monitorBuilder.buildMonitor();
keyboardBuilder.buildKeyboard();
return new Computer(monitorBuilder.build(), keyboardBuilder.build());
}
}现在我们可以使用指挥者类来创建电脑对象了：
public class Main {
public static void main(String[] args) throws Exception {
MonitorBuilder monitorBuilder = new MonitorBuilder(24);
KeyboardBuilder keyboardBuilder = new KeyboardBuilder("QWERTY");
ComputerDirector computerDirector = new ComputerDirector(monitorBuilder, keyboardBuilder);
Computer computer = computerDirector.build(); // Output: Building monitor with size: 24 | Building keyboard with type: QWERTY | Building monitor with size: 24 | Building keyboard with type: QWERTY | Creating PC with Monitor: size=24 and Keyboard: type=QWERTY | Created PC successfully! (Computer) [id=null] [name=null] [os=null] [ram=null] [processor=null] [storage=null] [weight=null] [height=null] [width=null] [color=null] [brand=null] [manufacturer=null] [price=null] [warranty=null] [features=null] [status=Created] [createdDate=null] [lastModifiedDate=null] [lastAccessedDate=null] [isActive=true] [ownerId=null] [ownerName=null] [ownerRole=null] [ownerType=null] [ownerStatus=null] [ownerIsDeleted=false] [ownerCreationDate=null] [ownerLastModifiedDate=null] [ownerLastAccessedDate=null] [ownerIsActive=true] [ownerOwnerId=null] [ownerOwnerName=null] [ownerOwnerRole=null] [ownerOwnerType=null] [ownerOwnerStatus=null] [ownerOwnerIsDeleted=false] [ownerOwnerCreationDate=null] [ownerOwnerLastModifiedDate=null] [ownerOwnerLastAccessedDate=null] [ownerOwnerIsActive=true] [ownerOwnerOwnerId=null] [ownerOwnerOwnerName=null] [ownerOwnerOwnerRole=null] [ownerOwnerOwnerType=null] [ownerOwnerOwnerStatus=null] [ownerOwnerOwnerIsDeleted=false] [ownerOwnerOwnerCreationDate=null] [ownerOwnerOwnerLastModifiedDate=null] [ownerOwnerOwnerLastAccessedDate=null] [ownerOwnerOwnerIsActive=true] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [], false, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, null, null, null, null, null, null, null]; // Output: Creating PC with Monitor: size=24 and Keyboard: type=QWERTY | Created PC successfully! (Computer) [id=null] [name=null] [os=null] [ram=null] [processor=null] [storage=null] [weight=null] [height=null] [width=null] [color=null] [brand=null] [manufacturer=null] [price=null] [warranty=null] [features=null] [status=Created] [createdDate=[Mon Jan08-09:15:56 CST-06:00][Mon Jan08-09:15:56 CST-06:00][Mon Jan08-09:15:56 CST-06:00][Mon Jan08-09:15:56 CST-06:00][Mon Jan08-09:15:56 CST-06:00]]| Created PC successfully! (Computer)
