有没有办法在没有 getter 或设置器的情况下制作推土机地图字段？（或者，什么映射器可以做到这一点？）

Question

这是一篇关于 Dozer 的文章：https://www.baeldung.com/dozer。它是一个映射器，使用反射将同名字段从一个对象映射到另一个对象（完全不相关的class）。

我想知道这是否可以灵活地用于私有字段、getters 和 setters。也就是说，

将 private String a 映射到另一个对象的 private String a 而没有任何 getters 或 setters 吗？
如果只有一侧有 getter 或 setter 怎么办（并且私有字段被命名为不同的名称以确保它不直接访问私有字段）？
如果一个 getter 而另一个 setter 完全不匹配私有字段怎么办？（但是 getter 和 setter 名称匹配。）

我在https://www.jdoodle.com/online-java-compiler中为运行写了一个测试程序：

import org.dozer.DozerBeanMapper;

public class Main {

    public static class MySource {

        // a -> a
        private String a;

        // getB() -> b
        private String hidden_b;
        public String getB() { return hidden_b; }

        // c -> setC(c)
        private String c;

        // getD() -> setD(d)
        private String hidden_d;

        // proper getters and setters on both sides
        private String proper;
        public String getProper() { return proper; }
        // public void setProper(String proper_) { proper = proper_; }

        public MySource() {
            a = "A Room with a View";
            hidden_b = "The Bridge of San Luis Rey";
            c = "Civilwarland in Bad Decline";
            hidden_d = "Darkness at Noon";
            proper = "This should copy, at minimum.";
        }

        public void print() {
            System.out.println("Source");
            System.out.println("================================");
            System.out.println("a        = " + a);
            System.out.println("hidden_b = " + hidden_b);
            System.out.println("c        = " + c);
            System.out.println("hidden_d = " + hidden_d);
            System.out.println("--------------------------------");
            System.out.println("proper   = " + proper);
            System.out.println("");
        }
    }

    public static class MyTarget {

        private String a;
        private String b;
        private String hidden_c;
        private String hidden_e;

        public void setC(String param) { hidden_c = param; }
        public void setD(String param) { hidden_e = param; }

        private String proper;
        // public String getProper() { return proper; }
        public void setProper(String proper_) { proper = proper_; }

        public MyTarget() {}

        public void print() {
            System.out.println("Target");
            System.out.println("================================");
            System.out.println("a        = " + a);
            System.out.println("b        = " + b);
            System.out.println("hidden_c = " + hidden_c);
            System.out.println("hidden_e = " + hidden_e);
            System.out.println("--------------------------------");
            System.out.println("proper   = " + proper);
            System.out.println("");
        }
    }

    public static void main(String args[]) {
        MySource s = new MySource();
        s.print();

        System.out.println("Now dozing...");
        System.out.println("");

        MyTarget t = new DozerBeanMapper().map(s, MyTarget.class);
        t.print();
    }
}

注意运行以上代码必须添加maven依赖：

Group ID:    net.sf.dozer
Artifact ID: dozer
Version:     5.5.1

而且您还必须尝试执行几次，因为随机超时取决于依赖项加载速度是否足够快。

无论如何，我的输出是：

Source
================================
a        = A Room with a View
hidden_b = The Bridge of San Luis Rey
c        = Civilwarland in Bad Decline
hidden_d = Darkness at Noon
--------------------------------
proper   = This should copy, at minimum.

Now dozing...

Target
================================
a        = null
b        = null
hidden_c = null
hidden_e = null
--------------------------------
proper   = This should copy, at minimum.

因此，看起来 Dozer 仅通过源上的 getter 和目标上的 setter 工作，这令人失望。或者，我没有正确使用它！

有没有办法让Dozer更灵活？或者，另一个可以实现此目的的映射器库？

Answer 1

好的，这是我的发现。希望这对某人有所帮助。

Dozer 5.5.1 应该能够通过 "class-level is-accessible." 执行此操作，但是，有 a bug。它已为未来版本修复，例如 Dozer 6.1+。（该包已移至新组，org.github.dozermapper。）虽然步骤有点复杂，但最终我放弃尝试 ModelMapper，它更好。所以这是我的代码。

包括这个包：

Group ID:    org.modelmapper
Artifact ID: modelmapper
Version:     2.3.2

使用方法如下：

import org.modelmapper.ModelMapper;
import org.modelmapper.config.Configuration;

public class Main {

    public static class MySource {

        // a -> a
        private String a;

        // getB() -> b
        private String hidden_b;
        public String getB() { return hidden_b; }

        // c -> setC(c)
        private String c;

        // getD() -> setD(d)
        private String hidden_d;

        // proper getters and setters on both sides
        private String proper;
        public String getProper() { return proper; }
        // public void setProper(String proper_) { proper = proper_; }

        public MySource() {
            a = "A Room with a View";
            hidden_b = "The Bridge of San Luis Rey";
            c = "Civilwarland in Bad Decline";
            hidden_d = "Darkness at Noon";
            proper = "This should copy, at minimum.";
        }

        public void print() {
            System.out.println("Source");
            System.out.println("================================");
            System.out.println("a        = " + a);
            System.out.println("hidden_b = " + hidden_b);
            System.out.println("c        = " + c);
            System.out.println("hidden_d = " + hidden_d);
            System.out.println("--------------------------------");
            System.out.println("proper   = " + proper);
            System.out.println("");
        }
    }

    public static class MyTarget {

        private String a;
        private String b;
        private String hidden_c;
        private String hidden_e;

        public void setC(String param) { hidden_c = param; }
        public void setD(String param) { hidden_e = param; }

        private String proper;
        // public String getProper() { return proper; }
        public void setProper(String proper_) { proper = proper_; }

        public MyTarget() {}

        public void print() {
            System.out.println("Target");
            System.out.println("================================");
            System.out.println("a        = " + a);
            System.out.println("b        = " + b);
            System.out.println("hidden_c = " + hidden_c);
            System.out.println("hidden_e = " + hidden_e);
            System.out.println("--------------------------------");
            System.out.println("proper   = " + proper);
            System.out.println("");
        }
    }

    public static void main(String args[]) {

        ModelMapper modelMapper = new ModelMapper();
        modelMapper.getConfiguration()
            .setFieldMatchingEnabled(true)
            .setFieldAccessLevel(Configuration.AccessLevel.PRIVATE);

        MySource s = new MySource();
        s.print();

        System.out.println("Now dozing...");
        System.out.println("");

        MyTarget t = modelMapper.map(s, MyTarget.class);
        t.print();
    }
}

这是我的输出：

Source
================================
a        = A Room with a View
hidden_b = The Bridge of San Luis Rey
c        = Civilwarland in Bad Decline
hidden_d = Darkness at Noon
--------------------------------
proper   = This should copy, at minimum.

Now dozing...

Target
================================
a        = A Room with a View
b        = The Bridge of San Luis Rey
hidden_c = Civilwarland in Bad Decline
hidden_e = null
--------------------------------
proper   = This should copy, at minimum.

第四个案例没有复制过来，但我真的不关心那个案例。我认为它可以通过不同的 ModelMapper 配置轻松实现。也许尝试松散复制。或者最坏的情况，在配置中手动绑定 getter 和 setter 方法。

Answer 2

Dozer 默认使用 getter 和 setter，但是您可以告诉 Dozer（通过映射）直接访问字段 http://dozer.sourceforge.net/documentation/custommethods.html

顺便说一句，Dozer 5 和 6 也包含基于 API 的映射。

有没有办法在没有 getter 或设置器的情况下制作推土机地图字段？ （或者，什么映射器可以做到这一点？）

Is there a way to make Dozer map fields without getter or setters? (Or, what mapper can do this?)

java

dozer

有没有办法在没有 getter 或设置器的情况下制作推土机地图字段？（或者，什么映射器可以做到这一点？）