Java设计模式之构建者模式

淡淡的烟草味﹌ 2023-09-24 12:49 136阅读 0赞

### 设计模式之构建者模式 ###

介绍两种写法

### 1.lombok构造器 ###

public class Builder {
        
    
        private int age;
        private String name;
    
        private Builder(){
        }
    
        public static Builder.BuilderHolder builder(){
        
            return new Builder.BuilderHolder();
        }
    
        public static class BuilderHolder{
        
            private int age;
            private String name;
    
            public BuilderHolder age(int age){
        
                this.age = age;
                return this;
            }
            public BuilderHolder name(String name){
        
                this.name = name;
                return this;
            }
    
            public Builder build(){
        
                Builder builder = new Builder();
                builder.age = this.age;
                builder.name = this.name;
                return builder;
            }
    
        }
    
    }

测试类

public class BuilderTest {
        
    
        public static void main(String[] args) {
        
            Builder builder = Builder.builder()
                    .age(1)
                    .name("张三")
                    .build();
        }
    
    }

### 2.自定义构造器 ###

public class Builder2<T> {
        
    
        private final Supplier<T> instance;
    
        private final  List<Consumer<T>> modifiers = new ArrayList<>();
    
        public Builder2(Supplier<T> instance) {
        
            this.instance = instance;
        }
    
        public static <T> Builder2<T> of(Supplier<T> instance) {
        
            return new Builder2<>(instance);
        }
    
        public <P> Builder2<T> with(BiConsumer<T, P> consumer, P p) {
        
            Consumer<T> c = instance -> consumer.accept(instance, p);
            modifiers.add(c);
            return this;
        }
    
        public T build() {
        
            T value = instance.get();
            modifiers.forEach(modifiers -> modifiers.accept(value));
            modifiers.clear();
            return value;
        }
    }

测试类

public class Test1 {
        
    
        public static void main(String[] args) {
        
            MsoShareOrder msoShareOrder = Builder2.of(MsoShareOrder::new)
                    .with(MsoShareOrder::setAgentName, "111")
                    .with(MsoShareOrder::setAgentNo, "666")
                    .with(MsoShareOrder::setMerNo, "A111")
                    .build();
        }
    
    }