关于代码的重构问题！！设计模式～原则！！谢谢大家！！！！

[Wuaner]

假设实体类ClassA有属性a b c d e f g.
现在我需要向ClassA对应表中插入六条记录。
其中a b字段是需要使用给定的值的（如：a需取遍"X,Y,Z,U,V,W",b在a取X、Y时取M，其他时候取N），
其他字段的值来自ClassB对应的字段。并且有下述要求：
对属性c：
若a取X,则c取classB.getX();
若a取Y,则c取classB.getY();
若a取Z,则c取classB.getZ();
若a取U,则c取classB.getU();
若a取V,则c取classB.getV();
若a取W：
if classB.getPar1=="CONSTANT1" 则c取"C1"
if classB.getPar1=="CONSTANT2" 则c取"C2"
else c取classB.getW();
属性d、e、f分别取用classB的par2、par3、par4即可。
当然，这样写肯定没错：

        ClassA ca1 = new ClassA();
        ca1.setA("X");
        ca1.setB("M");
        ca1.setC(classB.getPar1());
        ca1.setD(classB.getPar2());
        ca1.setE(classB.getPar3());
        ca1.setF(classB.getPar4());
        
        ClassA ca2 = new ClassA();
        ca2.setA("Y");
        ca2.setB("M");
        ca2.setC(classB.getY());
        ca2.setD(classB.getPar2());
        ca2.setE(classB.getPar3());
        ca2.setF(classB.getPar4());
        
        ClassA ca3 = new ClassA();
        ca3.setA("Z");
        ca3.setB("N");
        ca3.setC(classB.getZ());
        ca3.setD(classB.getPar2());
        ca3.setE(classB.getPar3());
        ca3.setF(classB.getPar4());
        
        ClassA ca4 = new ClassA();
        ca4.setA("U");
        ca4.setB("N");
        ca4.setC(classB.getU());
        ca4.setD(classB.getPar2());
        ca4.setE(classB.getPar3());
        ca4.setF(classB.getPar4());
        
        ClassA ca5 = new ClassA();
        ca5.setA("V");
        ca5.setB("N");
        ca5.setC(classB.getV());
        ca5.setD(classB.getPar2());
        ca5.setE(classB.getPar3());
        ca5.setF(classB.getPar4());
        
        ClassA ca6 = new ClassA();
        ca6.setA("W");
        ca6.setB("N");
        if(classB.getPar1()=="CONSTANT1") {
            ca6.setC("C1");
        } else if(classB.getPar1()=="CONSTANT2") {
            ca6.setC("C2");
        } else {
            ca6.setC(classB.getW());
        }
        ca6.setD(classB.getPar2());
        ca6.setE(classB.getPar3());
        ca6.setF(classB.getPar4());
        
        dao.save(ca1...6);

但这显然不是好的编码风格，重复的代码应该提出来。问下大家，欲重构的话，应该采用什么样的设计模式，或者需要遵循什么样的原则那?

谢谢大家！！！

[windforce9811]

模板加反射。

根据A的属性取值反射到B的属性。

剩余的动作提取一下，放到公用的方法里就OK了

[TillPerfect]

/*
 * 生成器接口
 */
interface BuilderClass
{
    public void buildA(String a);
    public void buildB(String a);
    public void buildC(String a, ClassB classB);
    public void buildD(String d);
    public void buildE(String e);
    public void buildF(String f);
    public ClassA getInstance();
}
/*
 * 具体的生成器
 */
class BuilderClassAA implements BuilderClass
{
    private String a;
    private String b;
    private String c;
    private String d;
    private String e;
    private String f;

    private static final String X = "X";
    private static final String Y = "Y";
    private static final String Z = "Z";
    private static final String U = "U";
    private static final String V = "V";
    private static final String W = "W";
    private static final String M = "M";
    private static final String N = "N";

    public void buildA(String a)
    {
        this.a = a;
    }
    public void buildB(String a)
    {
        b = (a.equals(X) || a.equals(Y)) ? M : N;
    }
    public void buildC(String a, ClassB classB)
    {
        if (a.equals(X))
        {
            c = classB.getX();
        }
        else if (a.equals(Y))
        {
            c = classB.getY();
        }
        else if (a.equals(Z))
        {
            c = classB.getZ();
        }
        else if (a.equals(U))
        {
            c = classB.getU();
        }
        else if (a.equals(V))
        {
            c = classB.getV();
        }
        else if (a.equals(classB.getW()))
        {
            c = classB.getW();
        }
    }
    public void buildD(String d)
    {
        this.d = d;
    }
    public void buildE(String e)
    {
        this.e = e;
    }
    public void buildF(String f)
    {
        this.f = f;
    }
    public ClassA getInstance()
    {
        return new ClassA(a, b, c, d, e, f);
    }
}
/*
 * 用于构建最终的对象
 */
class Product
{
    private BuilderClass builder;

    public Product(BuilderClass builder)
    {
        this.builder = builder;
    }

    public void build(String a, ClassB classB)
    {
        builder.buildA(a);
        builder.buildB(a);
        builder.buildC(a, classB);
        builder.buildD(classB.getPar2());
        builder.buildE(classB.getPar3());
        builder.buildF(classB.getPar4());
    }
}
/*
 * 调用生成器
 */
public class BuilderClassA
{
    public static void main(String[] args)
    {
        ClassB cb = new ClassB("par1", "par2", "par3", "par4", "xxx", "yyy","zzz", "uuu", "vvv", "www");
        String a = "X";
        BuilderClass builder = new BuilderClassAA();
        Product finalBuilder = new Product(builder);
        finalBuilder.build(a, cb);
        ClassA ca = builder.getInstance();
        System.out.println(ca.getA() + "  " + ca.getB() + "  " + ca.getC());
    }
}

[TillPerfect]

额。。。写得有点多啊。。。
反正就是这个意思
lz记得要进行判空操作，避免空指针。我没有写

[火龙果被占用了]

没明白要做什么，而且楼主举的例子也很敷衍！

[narcissusoyf]

不用builder 那么多。。而且，如果你的builer是这样写的话，给写客户端代码的人会带来很阴郁的感觉。。。对于builder的中间过程，尽量采取方法链的形式。要保证创建过程不被打断。另外，有个明确的方法返回你要创建的最终对象。

public class Builder
{
private ClassB b ;

private ClassA aa;

public Builder(ClassB b)
{
this.b = b;
}


public Builder setA(A a)
{
aa = new ClassA ();
aa.setA(a);
if(a == "x")
{
aa.setB("m");
aa.setC(b.getX());
}
else if(a == "y")
{
aa.setB("m");
aa.setC(b.getY());
}
else if(a == "z")
{
aa.setB("m");
aa.setC(b.getZ());
}
else if(a == "u")
{
aa.setB("n");
aa.setC(b.getU());
}
else if(a == "v")
{
aa.setB("n");
aa.setC(b.getV());
}
else if(a == "w")
{
aa.setB("n");
if(b.getPart1() == "C1")
aa.setC("C1");
else if(b.getPart1() == "C2")
aa.setC("C2");
else
aa.setC(b.getW());
}
aa.setD(b.getPart2());
aa.setE(b.getPart3());
aa.setF(b.getPart4());


return this;
}


public ClassA createClassA()
{
if(aa == null)
throw new RuntimeException("");
return aa;
}


public static void main(String[] args)
{
ClassB b = new ClassB();
A a = new A("x");
//...
ClassA a = (new Builder(b)).setA().createClassA();
}
}

[sotom]

抢个so far.

[Wuaner]

沙发抢这么快。。。刚要改个错误。。。这下倒好，又改不了了。。

代码第四行该是

ca1.setC(classB.getX());

[goosman]

分支太多了....就不写代码了...

我的看法还是用工厂比较好....如果数据只是由classB给定, 那么工厂的接口就只接受classB实例

[Monkey_D_Luffy]

还没学到这一课，但是帮顶一下，希望楼主能尽快解决问题

[重返春季]

/*
 * 生成器接口
 */
interface BuilderClass
{
    public void buildA(String a);
    public void buildB(String a);
    public void buildC(String a, ClassB classB);
    public void buildD(String d);
    public void buildE(String e);
    public void buildF(String f);
    public ClassA getInstance();
}
/*
 * 具体的生成器
 */
class BuilderClassAA implements BuilderClass
{
    private String a;
    private String b;
    private String c;
    private String d;
    private String e;
    private String f;

    private static final String X = "X";
    private static final String Y = "Y";
    private static final String Z = "Z";
    private static final String U = "U";
    private static final String V = "V";
    private static final String W = "W";
    private static final String M = "M";
    private static final String N = "N";

    public void buildA(String a)
    {
        this.a = a;
    }
    public void buildB(String a)
    {
        b = (a.equals(X) || a.equals(Y)) ? M : N;
    }
    public void buildC(String a, ClassB classB)
    {
        if (a.equals(X))
        {
            c = classB.getX();
        }
        else if (a.equals(Y))
        {
            c = classB.getY();
        }
        else if (a.equals(Z))
        {
            c = classB.getZ();
        }
        else if (a.equals(U))
        {
            c = classB.getU();
        }
        else if (a.equals(V))
        {
            c = classB.getV();
        }
        else if (a.equals(classB.getW()))
        {
            c = classB.getW();
        }
    }
    public void buildD(String d)
    {
        this.d = d;
    }
    public void buildE(String e)
    {
        this.e = e;
    }
    public void buildF(String f)
    {
        this.f = f;
    }
    public ClassA getInstance()
    {
        return new ClassA(a, b, c, d, e, f);
    }
}
/*
 * 用于构建最终的对象
 */
class Product
{
    private BuilderClass builder;

    public Product(BuilderClass builder)
    {
        this.builder = builder;
    }

    public void build(String a, ClassB classB)
    {
        builder.buildA(a);
        builder.buildB(a);
        builder.buildC(a, classB);
        builder.buildD(classB.getPar2());
        builder.buildE(classB.getPar3());
        builder.buildF(classB.getPar4());
    }
}
/*
 * 调用生成器
 */
public class BuilderClassA
{
    public static void main(String[] args)
    {
        ClassB cb = new ClassB("par1", "par2", "par3", "par4", "xxx", "yyy","zzz", "uuu", "vvv", "www");
        String a = "X";
        BuilderClass builder = new BuilderClassAA();
        Product finalBuilder = new Product(builder);
        finalBuilder.build(a, cb);
        ClassA ca = builder.getInstance();
        System.out.println(ca.getA() + "  " + ca.getB() + "  " + ca.getC());
    }
}

[henry_fuzr]

面向对象的思想 考虑 ClassA和ClassB存在什么关系

[wn_1985]

你这对象模型设计的好别扭

[Wuaner]

[Quote=引用 15 楼 wn_1985 的回复:]
你这对象模型设计的好别扭
[/Quote]

这是一个非常大的系统，它就是这样设计的，我也没办法啊。。。

[Wuaner]

继续给答案啊。。。。。。。。。。。。。

[guoyueshan]

似乎其他属性的值都是由a的值决定的，那么可以用状态模式，a的值决定这个对象的状态，a的取值有几种可能性，就有几种状态，这样扩充起来也很方便。

[Wuaner]

谢谢大家的热心回复！！！！！！

请继续 ！

[wzl_00]

都是高手呵！

[manutdsodagreen]

推荐你看看这个：
http://www.vincehuston.org/dp/factory_method.html
或者 整体的DP 23种

http://www.vincehuston.org/dp/

[验证码识别]

MARK


学习

[Wuaner]

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