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。