本人在学习Java，直接先学习Netty框架，因为Netty框架是业界最流行的NIO框架之一，在学习的过程中，了解到Netty服务端启动需要先创建服务器启动辅助类ServerBootstrap，它提供了一系列的方法用于设置服务器端启动相关的参数。然而在创建ServerBootstrap实例时，发现ServerBootstrap只有一个无参的构造函数，事实上它需要与多个其它组件或者类交互。ServerBootstrap构造函数没有参数的原因是因为它的参数太多了，而且未来也可能会发生变化。Netty创造者为了解决这个问题，就引入了Builder模式。
学习到这里，在IOS开发中，我虽然也研习过23中常用的设计模式，但是我却从没听过的Builder模式，于是就开始了探索Builder模式，并尝试用OC语言去模仿实现这种模式。说不定以后在iOS开发中会用到呢。
Java的实例源码：
1 public class DoDoContact { 2 3 private final int age; 4 private final int safeID; 5 private final String name; 6 private final String address; 7 8 public int getAge() { 9 return age;10 }11 12 public int getSafeID() {13 return safeID;14 }15 16 public String getName() {17 return name;18 }19 20 public String getAddress() {21 return address;22 }23 24 public static class Builder {25 private int age = 0;26 private int safeID = 0;27 private String name = null;28 private String address = null;29 30 public Builder(String name) {31 this.name = name;32 }33 34 public Builder age(int val) {35 age = val;36 return this;37 }38 39 public Builder safeID(int val) {40 safeID = val;41 return this;42 }43 44 public Builder address(String val) {45 address = val;46 return this;47 }48 49 public DoDoContact build() {50 return new DoDoContact(this);51 }52 }53 54 private DoDoContact(Builder b) {55 age = b.age;56 safeID = b.safeID;57 name = b.name;58 address = b.address;59 60 }61 } java的main函数
1 public class Test2{2 public static void main(String[] args) {3 DoDoContact ddc = new DoDoContact.Builder("Ace").age(10)4 .address("beijing").build();5 System.out.println("name=" + ddc.getName() + "age =" + ddc.getAge()6 + "address" + ddc.getAddress());7 }8 } 有木有发现在main函数中，创建一个对象，却可以动态的传入参数。
下面使用OC来实现：
DoDoContact.h
1 #import2 3 @class Builder; 4 5 @interface DoDoContact : NSObject 6 7 @property (nonatomic,assign) NSInteger age; 8 @property (nonatomic,assign) NSInteger safeID; 9 @property (nonatomic,strong) NSString *name;10 @property (nonatomic,strong) NSString *address;11 12 + (Builder*)getBulder;13 14 @end
DoDoContact.m
1 #import "DoDoContact.h" 2 3 4 @interface Builder () 5 6 @property (nonatomic,assign) NSInteger age; 7 @property (nonatomic,assign) NSInteger safeID; 8 @property (nonatomic,strong) NSString *name; 9 @property (nonatomic,strong) NSString *address;10 11 @end12 13 14 @interface DoDoContact ()15 16 17 @end18 19 @implementation DoDoContact20 21 - (instancetype)initWith:(Builder*)builder22 {23 self = [super init];24 if (self) {25 self.age = builder.age;26 self.safeID = builder.safeID;27 self.name = builder.name;28 self.address = builder.address;29 }30 return self;31 }32 33 + (instancetype)getDoDoContactWith:(Builder*)builder{34 DoDoContact *doDoContact = [[DoDoContact alloc] initWith:builder];35 return doDoContact;36 }37 38 + (Builder*)getBulder{39 return [Builder new];40 }41 42 @end43 44 45 46 @implementation Builder47 48 - (instancetype)init49 {50 self = [super init];51 if (self) {52 _age = 0;53 _safeID = 0;54 _name = NULL;55 _address = NULL;56 }57 return self;58 }59 60 - (Builder*)age:(NSInteger)age{61 self.age = age;62 return self;63 }64 65 - (Builder*)safeID:(NSInteger)safeID{66 self.safeID = safeID;67 return self;68 }69 70 - (Builder*)name:(NSString*)name{71 self.name = name;72 return self;73 }74 - (Builder*)address:(NSString*)address{75 self.address = address;76 return self;77 }78 79 - (DoDoContact*)getDoDoContact{80 return [DoDoContact getDoDoContactWith:self];81 }82 83 84 @end 再来看创建DoDoContact对象的方式，本人这里无意中用的是IOS工程所以直接在ViewController类中创建了。
虽然也是可以动态传入参数，但是OC的语言风格却不好看。但是用Swift可以，毕竟Swift也模仿了java的class类。