将构建器放在单独的类中（流利的界面）

使用组成。为了使事情变得更加轻松和整洁，请不要在source（

Foo

Builder

例如，在

Foo

Builder

Foo

简单的代码段：

import java.util.*;class UserBasicInfo{    String nickName;    String birthDate;    String gender;    public UserBasicInfo(String name,String date,String gender){        this.nickName = name;        this.birthDate = date;        this.gender = gender; }    public String toString(){        StringBuilder sb = new StringBuilder();        sb.append("Name:DOB:Gender:").append(nickName).append(":").append(birthDate).append(":").        append(gender);        return sb.toString();    }}class ContactInfo{    String eMail;    String mobileHome;    String mobileWork;    public ContactInfo(String mail, String homeNo, String mobileOff){        this.eMail = mail;        this.mobileHome = homeNo;        this.mobileWork = mobileOff;    }        public String toString(){        StringBuilder sb = new StringBuilder();        sb.append("email:mobile(H):mobile(W):").append(eMail).append(":").append(mobileHome).append(":").append(mobileWork);        return sb.toString();    }}class FaceBookUser {    String userName;    UserBasicInfo userInfo;    ContactInfo contactInfo;    public FaceBookUser(String uName){        this.userName = uName;    }        public void setUserBasicInfo(UserBasicInfo info){        this.userInfo = info;    }    public void setContactInfo(ContactInfo info){        this.contactInfo = info;    }        public String getUserName(){        return userName;    }    public UserBasicInfo getUserBasicInfo(){        return userInfo;    }    public ContactInfo getContactInfo(){        return contactInfo;    }    public String toString(){        StringBuilder sb = new StringBuilder();        sb.append("|User|").append(userName).append("|UserInfo|").append(userInfo).append("|ContactInfo|").append(contactInfo);        return sb.toString();    }    static class FaceBookUserBuilder{        FaceBookUser user;        public FaceBookUserBuilder(String userName){ this.user = new FaceBookUser(userName);        }        public FaceBookUserBuilder setUserBasicInfo(UserBasicInfo info){ user.setUserBasicInfo(info); return this;        }        public FaceBookUserBuilder setContactInfo(ContactInfo info){ user.setContactInfo(info); return this;        }        public FaceBookUser build(){ return user;        }    }}public class BuilderPattern{    public static void main(String args[]){        FaceBookUser fbUser1 = new FaceBookUser.FaceBookUserBuilder("Ravindra").build(); // Mandatory parameters        UserBasicInfo info = new UserBasicInfo("sunrise","25-May-1975","M");        // Build User name + Optional Basic Info         FaceBookUser fbUser2 = new FaceBookUser.FaceBookUserBuilder("Ravindra").    setUserBasicInfo(info).build();        // Build User name + Optional Basic Info + Optional Contact Info        ContactInfo cInfo = new ContactInfo("xxx@xyz.com","1111111111","2222222222");        FaceBookUser fbUser3 = new FaceBookUser.FaceBookUserBuilder("Ravindra").    setUserBasicInfo(info).    setContactInfo(cInfo).build();        System.out.println("Facebook user 1:"+fbUser1);        System.out.println("Facebook user 2:"+fbUser2);        System.out.println("Facebook user 3:"+fbUser3);    }}

输出：

Facebook user 1:|User|Ravindra|UserInfo|null|ContactInfo|nullFacebook user 2:|User|Ravindra|UserInfo|Name:DOB:Gender:sunrise:25-May-1975:M|ContactInfo|nullFacebook user 3:|User|Ravindra|UserInfo|Name:DOB:Gender:sunrise:25-May-1975:M|ContactInfo|email:mobile(H):mobile(W):xxx@xyz.com:1111111111:2222222222

说明：

1. FaceBookUser

   是一个复杂对象，具有以下使用合成的属性：

   String userName;

   UserBasicInfo userInfo;
   ContactInfo contactInfo;
   

2. FaceBookUserBuilder

   是静态构建器类，其中包含和builds

   FaceBookUser

   。

3. userName是构建FaceBookUser的唯一必需参数

4. FaceBookUserBuilder

   建立

   FaceBookUser

   通过设置可选参数：

   UserBasicInfo

   和

   ContactInfo

5. 本示例说明了

   FaceBookUsers

   从Builder构建的具有不同属性的三个不同属性。
   1. fbUser1被构建为仅具有userName属性的FaceBookUser
   2. fbUser2被构建为FaceBookUser，具有userName和UserBasicInfo
   3. fbUser3被构建为FaceBookUser，具有userName，UserBasicInfo和ContactInfo

在此示例中，已使用合成，而不是在Builder类中复制FaceBookUser的所有属性。

编辑：

将所有相关属性分组为逻辑类。在FaceBookUser中定义所有这些类。不必在类中的

Builder

FaceBookUser

Builder

为简单起见，我添加了两个类：UserBasicInfo和ContactInfo。现在，使用其他属性将这个FaceBookUser类爆炸

NewsFeedMessagesFriendsAlbumsEventsGamesPagesAds

等等

如果您在

Builder

FaceBookUser

FaceBookUser

FaceBookUserBuilder

添加以上属性后，您将

FaceBookUser

它将是这样的：

FaceBookUser fbUser3 = new FaceBookUser.FaceBookUserBuilder("Ravindra").       setUserBasicInfo(info).       setNewsFeed(newsFeed).       setMessages(messages).       setFriends(friends).       setAlbums(albums).       setEvents(events).       setGames(games).       setAds(ads).build();