建造者模式是运用于构建复杂对象时的一种设计模式
经典模式
经典的Builder模式分为以下四个角色：
- 要建造的产品
Product
- 抽象的
Builder
Builder的具体实现ConcreteBuilder- 使用者
Director
Product
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| public class Computer {
private String CPU;
private String memory;
private String hardDisk;
private String keyboard;
private String mouse;
public String getCPU() {
return CPU;
}
public void setCPU(String CPU) {
this.CPU = CPU;
}
public String getMemory() {
return memory;
}
public void setMemory(String memory) {
this.memory = memory;
}
public String getHardDisk() {
return hardDisk;
}
public void setHardDisk(String hardDisk) {
this.hardDisk = hardDisk;
}
public String getKeyboard() {
return keyboard;
}
public void setKeyboard(String keyboard) {
this.keyboard = keyboard;
}
public String getMouse() {
return mouse;
}
public void setMouse(String mouse) {
this.mouse = mouse;
}
@Override
public String toString() {
return "Computer{" +
"CPU='" + CPU + '\'' +
", memory='" + memory + '\'' +
", hardDisk='" + hardDisk + '\'' +
", keyboard='" + keyboard + '\'' +
", mouse='" + mouse + '\'' +
'}';
}
}
|
Builder
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| public interface ComputerConfigBuilder {
void setCPU();
void setMemery();
void setHardDisk();
void setKeyboard();
void setMouse();
Computer getComputer();
}
|
ConcreteBuilder
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| public class LowConfigBuilder implements ComputerConfigBuilder {
private Computer mComputer;
public LowConfigBuilder(){
this.mComputer = new Computer();
}
@Override
public void setCPU() {
mComputer.setCPU("i5");
}
@Override
public void setMemery() {
mComputer.setMemory("8G");
}
@Override
public void setHardDisk() {
mComputer.setHardDisk("500G");
}
@Override
public void setKeyboard() {
mComputer.setKeyboard("薄膜键盘");
}
@Override
public void setMouse() {
mComputer.setMouse("有线鼠标");
}
@Override
public Computer getComputer() {
return mComputer;
}
}
|
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| public class HighConfigBuider implements ComputerConfigBuilder {
private Computer mComputer;
public HighConfigBuider(){
this.mComputer = new Computer();
}
@Override
public void setCPU() {
mComputer.setCPU("i7");
}
@Override
public void setMemery() {
mComputer.setMemory("16G");
}
@Override
public void setHardDisk() {
mComputer.setHardDisk("1T");
}
@Override
public void setKeyboard() {
mComputer.setKeyboard("机械键盘");
}
@Override
public void setMouse() {
mComputer.setMouse("无线鼠标");
}
@Override
public Computer getComputer() {
return mComputer;
}
}
|
Director
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| public class Director {
private ComputerConfigBuilder mBuilder;
public void setBuilder(ComputerConfigBuilder builder){
this.mBuilder = builder;
}
public void createComputer(){
mBuilder.setCPU();
mBuilder.setMemery();
mBuilder.setHardDisk();
mBuilder.setKeyboard();
mBuilder.setMouse();
}
public Computer getComputer(){
return mBuilder.getComputer();
}
}
|
如上所示，Director使用不同的Builder即可构造出完全不同的Product。
变种Builder模式
这个变种在实际开发中运用的较多，主要用于成员变量过多的类的对象。
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| public class Person {
private String name;
private final String gender;
private final String age;
private final String shoes;
private final String clothes;
private final String money;
private final String house;
private final String car;
private final String career;
private Person(Builder builder) {
this.name = builder.name;
this.gender = builder.gender;
this.age = builder.age;
this.shoes = builder.shoes;
this.clothes = builder.clothes;
this.money = builder.money;
this.house = builder.house;
this.car = builder.car;
this.career = builder.career;
}
public static class Builder {
private String name;
private String gender;
private String age;
private String shoes;
private String clothes;
private String money;
private String house;
private String car;
private String career;
public Builder(String name,String gender) {
this.name = name;
this.gender = gender;
}
public Builder age(String age) {
this.age = age;
return this;
}
public Builder car(String car) {
this.car = car;
return this;
}
public Builder shoes(String shoes) {
this.shoes = shoes;
return this;
}
public Builder clothes(String clothes) {
this.clothes = clothes;
return this;
}
public Builder money(String money) {
this.money = money;
return this;
}
public Builder house(String house) {
this.house = house;
return this;
}
public Builder career(String career) {
this.career = career;
return this;
}
public Person build(){
return new Person(this);
}
}
}
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使用构造者来构造对象：
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| Person person = new Person.Builder("张三","男")
.age("12")
.money("1000000")
.car("宝马")
.build();
|
