将对象转换为其他类型，包括对象列表

Question

我有一个对象的问题。实际上，我必须把一个物体转换成另一个物体。在我的Category对象中包含一个类别（子类别）列表。这段代码中的主要问题是我们必须将所有子类别（Category对象）转换为CatgoryUI。

   import java.util.ArrayList;
import java.util.List;
public class TestMain {
    /**
     * @param args
     */
    public static void main(String[] args) {
        System.out.println("In main");
        TestMain tm = new TestMain();
        List<Category> categories= tm.prepareList();
        tm.displayCategories(categories);
        List<CategoryUI> categoryList = tm.convertCategories(categories);
        System.out.println("------Converted------");
        tm.displayConvertedCategories(categoryList);
    }
    private List<Category> prepareList(){
        //Category category = new Category();
        List<Category> level3List1 = new ArrayList<Category>();
        level3List1.add(new Category(4L, "Sentence Equalence", new ArrayList<Category>()));
        level3List1.add(new Category(5L, "Antonyms", new ArrayList<Category>()));
        level3List1.add(new Category(6L, "Text Completion", new ArrayList<Category>()));
        List<Category> level3List2 = new ArrayList<Category>();
        level3List2.add(new Category(7L, "Problem Solving", new ArrayList<Category>()));
        level3List2.add(new Category(8L, "Logical Reasoning", new ArrayList<Category>()));
        List<Category> level2List = new ArrayList<Category>();
        level2List.add(new Category(2L, "Verbal", level3List1));
        level2List.add(new Category(3L, "Quantative", level3List2));
        List<Category> level1List = new ArrayList<Category>();
        level1List.add(new Category(1L, "GRE", level2List));
        return level1List;
    }
    private void displayCategories(List<Category> categories){
        System.out.println("<ul>");
        for(Category category : categories){
            System.out.println("<li>");
            System.out.println(category.getName());
            System.out.println("</li>");
            if(category.getSubCategory().size()>0){
                displayCategories(category.getSubCategory());
            }
        }
        System.out.println("</ul>");
    }
}
package net.sankhya.debug;
import java.util.List;
public class Category {
    private Long id;
    private String name;
    private List<Category> subCategory;

    public Category(Long id, String name, List<Category> subCategory) {
        super();
        this.id = id;
        this.name = name;
        this.subCategory = subCategory;
    }
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public List<Category> getSubCategory() {
        return subCategory;
    }
    public void setSubCategory(List<Category> subCategory) {
        this.subCategory = subCategory;
    }
}
package net.sankhya.debug;
import java.util.List;
public class CategoryUI {
    private Long id;
    private String name;
    private List<CategoryUI> subCategory;
    public CategoryUI(){
    }
    public CategoryUI(Long id, String name, List<CategoryUI> subCategory) {
        super();
        this.id = id;
        this.name = name;
        this.subCategory = subCategory;
    }
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public List<CategoryUI> getSubCategory() {
        return subCategory;
    }
    public void setSubCategory(List<CategoryUI> subCategory) {
        this.subCategory = subCategory;
    }
}

当你在html视图中用ul和li显示类别列表时，它将显示如下。并且在转换成CategoryUI对象后，如果打印列表，它也应该以同样的方式播放。所以，请大家就如何将Category转换为CategoryUI给出一些建议。

<ul>
<li>GRE</li>
<ul>
    <li>Verbal</li>
    <ul>
        <li>Sentence Equalence</li>
        <li>Antonyms</li>
        <li>Text Completion</li>
    </ul>
    <li>Quantative</li>
    <ul>
        <li>Problem Solving</li>
        <li>Logical Reasoning</li>
    </ul>
</ul>

感谢

Answer 1

编写自己的转换方法，如下所示。。。

public List<CategoryUI> convertArray(List<Category> categoryArray){
    List<CategoryUI> convertedArray = new ArrayList<CategoryUI>();
    for (int i=0;i<categoryArray.size();i++){
        convertedArray.add(convertObject(categoryArray.get(i)));
    }
    return convertedArray;
}

public CategoryUI convertObject(Category category){
    return new CategoryUI(category.getId(),category.getName(),convertArray(category.getSubCategory()));
}

只需为每个要转换的对象调用convertObject(category)。您可以创建一个正确类型的新对象，并用旧对象中的所有数据填充它。它还转换子类别的数组。如果您传入树的顶部节点，那么一个调用将遍历树的所有子类别并转换所有子类别，因此非常简单。

Answer 2

如果需要在应用程序中更频繁地使用Dozer，也可以考虑使用它它将自动执行映射。