> Build
---
定义：将一个复杂对象的构建与它的表示分离，使得同样的构建过程可以创建不同的表示。
特征：用户只需指定需要建造的类型就可以得到他们，建造过程及细节不需要知道。
类型：创建型[如果一步一步构建包含多个组件的过程,相同的构建对象可以构建出不同的产品]
适用于：流程固定，而顺序不一定固定的业务。[如果一个对象有非常复杂的内部结构(很多属性)、想把复杂对象的创建和使用分离]
优点：封装性好，创建和使用分离。扩展性好，建造类之间独立，一定程度上解耦
缺点：产生多余的Builder对象。产品内部发生变化，建造者都要修改，成本较大
- Demo1
```
public class CourseSecondVersion {
private String courseQA;
private String coursePPT;
private String courseName;
private String courseVideo;
private String courseArticle;
@Override
public String toString() {
return "CourseSecondVersion{" +
"courseQA='" + courseQA + '\'' +
", coursePPT='" + coursePPT + '\'' +
", courseName='" + courseName + '\'' +
", courseVideo='" + courseVideo + '\'' +
", courseArticle='" + courseArticle + '\'' +
'}';
}
public CourseSecondVersion(CourseBuild courseBuild) {
this.courseQA = courseBuild.courseQA;
this.coursePPT = courseBuild.coursePPT;
this.courseName = courseBuild.courseName;
this.courseVideo = courseBuild.courseVideo;
this.courseArticle = courseBuild.courseArticle;
}
public static class CourseBuild {
private String courseQA;
private String coursePPT;
private String courseName;
private String courseVideo;
private String courseArticle;
public CourseBuild buildCourseName(String courseName) {
this.courseName = courseName + "----------this is name-------" + courseName;
return this;
}
public CourseBuild buildCourseQA(String courseQA) {
this.courseQA = courseQA;
return this;
}
public CourseBuild buildCoursePPT(String coursePPT) {
this.coursePPT = coursePPT;
return this;
}
public CourseBuild buildCourseVideo(String courseVideo) {
this.courseVideo = courseVideo;
return this;
}
public CourseBuild buildCourseArticle(String courseArticle) {
this.courseArticle = courseArticle;
return this;
}
public CourseSecondVersion build() {
return new CourseSecondVersion(this);
}
}
}
```
- Demo2
```
// 封装组件
public class KillPeopleBuilder {
private String makeGun;
private String buyGunpowder;
private String makeBullet;
private String AssemblySomeGuns;
private String Aim;
private String killHead;
@Override
public String toString() {
return "KillPeopleBuilder{" +
"makeGun='" + makeGun + '\'' +
", buyGunpowder='" + buyGunpowder + '\'' +
", makeBullet='" + makeBullet + '\'' +
", AssemblySomeGuns='" + AssemblySomeGuns + '\'' +
", Aim='" + Aim + '\'' +
", killHead='" + killHead + '\'' +
'}';
}
public KillPeopleBuilder(GoBuild build) {
this.Aim = build.aim;
this.makeGun = build.makeGun;
this.killHead = build.killHead;
this.makeBullet = build.makeBullet;
this.buyGunpowder = build.buyGunPowder;
this.AssemblySomeGuns = build.assemblySomeGuns;
}
public static class GoBuild {
private String makeGun;
private String buyGunPowder;
private String makeBullet;
private String assemblySomeGuns;
private String aim;
private String killHead;
public GoBuild buildMakeGun(String makeGun) {
this.makeGun = makeGun;
return this;
}
public GoBuild buildBuyGunPower(String buyGunPowder) {
this.buyGunPowder = buyGunPowder;
return this;
}
public GoBuild buildMakeBullet(String makeBullet) {
this.makeBullet = makeBullet;
return this;
}
public GoBuild buildAssemblySomeGuns(String assemblySomeGuns) {
this.assemblySomeGuns = assemblySomeGuns;
return this;
}
public GoBuild buildAim(String aim) {
this.aim = aim;
return this;
}
public GoBuild buildKillHead(String killHead) {
this.killHead = killHead;
return this;
}
public KillPeopleBuilder build() {
return new KillPeopleBuilder(this);
}
}
}
```
```
// 调用组件
public class IWannaKillPeoples {
public static void main(String[] args) {
KillPeopleBuilder build = new KillPeopleBuilder.GoBuild().buildMakeGun("开始造枪的步骤").buildMakeBullet("买好火药和子弹").buildAim("瞄准敌人").buildKillHead("爆头").build();
System.out.println(build.toString());
}
}
```
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