Java编程设计2

一般我们会以这种设计方式生产对象实例，如：

创建一个接口：

public interface TestOpen {

    String getVirtualHost();

    String getCapabilities();

    boolean getInsist();

}

实现该接口：

public class TestOpenImpl implements TestOpen {

    private String t1;
    private String t2;
    private String t3;
    public TestOpenImpl()
    {

    }
    public TestOpenImpl(String t1,String t2,String t3)
    {
        //doSomething...
    }
    @Override
    public String getVirtualHost() {
        return null;
    }

    @Override
    public String getCapabilities() {
        return null;
    }

    @Override
    public boolean getInsist() {
        return false;
    }
}

创建一个构造器：

public class TestOpenBuilder {
    public static  TestOpen Build()
    {
        return new TestOpenImpl();
    }
    public static  TestOpen Build(String t1,String t2,String t3)
    {
        return new TestOpenImpl(t1,t2,t3);
    }
}

所以在构造实例对象时，需要：

TestOpenBuilder.Build()或TestOpenBuilder.Build("","","");

如果将构造器封装在interface中，如这样所示：

public interface TestOpen {

    String getVirtualHost();

    String getCapabilities();

    boolean getInsist();

    final class Build
    {
        private   String t1;
        private String t2;
        private String t3;
        public   TestOpen.Build t1(String t1){

            this.t1=t1;
            return this;
        }
        public TestOpen.Build t2(String t2){

            this.t2=t1;
            return this;
        }
        public TestOpen.Build t3(String t3){

            this.t3=t3;
            return this;
        }
        public TestOpen build()
        {
            return new TestOpenImpl(this.t1,this.t2,this.t3);
        }
    }

}

则我们在构造时，可以这样：

TestOpen testOpen = new TestOpen.Build().t1("haha").t2("21").t3("23").build();

这样做的好处：可以将接口与其构建器关联起来，方便使用。