java data dictionary (parent-child structure) bound to a set of List

The java data dictionary (parent-child structure) bind to List collection, in order to achieve database synchronization
recent company to do a project, which is a function of the local database synchronization to a remote server, the synchronization process is not the focus of this article, focus is on the import process, involving a type of data dictionary table, which is the parent table with ID, that (his son table), which the proposed new import requirements: that is, when the new import table You must import the parent table, and then import the child table, if the multi-level, then sequentially introduced from the top-down start, leading a meal and I said, what ah while loop, recursive ah, to be honest, I know he wants to express meaning, but I could not write, can not look for the Internet, and finally I saw the one-sided article:

Kaer_GG article, tree-list (menu tree) recursive traversal list helped me a lot, well, does not cost, then I look at the database structure:
, well, then the corresponding entities for everyone to see

package com.ringchi.entity.department;

import com.ringchi.entity.NamedObject;
import com.ringchi.entity.NamedTreeObject;
import com.ringchi.entity.dictionary.Dictionary;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import javax.persistence.Transient;

@Entity
@Table(name="basic_department")
public class Department extends NamedObject
  implements NamedTreeObject
{
  private static final long serialVersionUID = 3256440322035822899L;
  private String assignedCode;
  private String abbreviation;
  private Dictionary type;
  private Dictionary kind;
  private Date createDate;
  private Date dropDate;
  private int sequence;
  private String location;
  private Department parent;
  private Dictionary level;
  private String levelCode;

  public Department()
  {
  }

  public Department(String id)
  {
    super(id);
  }

  public Department(String id, String name) {
    super(id, name);
  }

  @Column(length=20)
  public String getAbbreviation()
  {
    return this.abbreviation;
  }

  public void setAbbreviation(String abbreviation)
  {
    this.abbreviation = abbreviation;
  }
  @Column(length=20)
  public String getAssignedCode() {
    return this.assignedCode;
  }

  public void setAssignedCode(String assignedCode) {
    this.assignedCode = assignedCode;
  }

  @Temporal(TemporalType.DATE)
  public Date getCreateDate()
  {
    return this.createDate;
  }

  public void setCreateDate(Date createDate)
  {
    this.createDate = createDate;
  }

  @ManyToOne
  @JoinColumn(name="Type")
  public Dictionary getType()
  {
    return this.type;
  }

  public void setType(Dictionary type)
  {
    this.type = type;
  }

  @Temporal(TemporalType.DATE)
  public Date getDropDate()
  {
    return this.dropDate;
  }

  public void setDropDate(Date dropDate)
  {
    this.dropDate = dropDate;
  }

  public int getSequence()
  {
    return this.sequence;
  }

  public void setSequence(int sequence)
  {
    this.sequence = sequence;
  }

  @ManyToOne
  @JoinColumn(name="Parent")
  public Department getParent()
  {
    return this.parent;
  }

  public void setParent(Department parent)
  {
    this.parent = parent;
  }

  public String toString()
  {
    String result = getId() + ":" + getName() + "[";
    if (getParent() != null) {
      result = result + "{" + getParent().getId() + "} ";
    }
    result = result + "]";
    return result;
  }
  @Transient
  public NamedTreeObject getTreeParent() {
    return getParent();
  }

  public void setTreeParent(NamedTreeObject parent) {
    setParent((Department)parent);
  }
  @ManyToOne
  @JoinColumn(name="Level")
  public Dictionary getLevel() { return this.level; }

  public void setLevel(Dictionary level)
  {
    this.level = level;
  }
  @ManyToOne
  @JoinColumn(name="Kind")
  public Dictionary getKind() { return this.kind; }

  public void setKind(Dictionary kind)
  {
    this.kind = kind;
  }
  @Column(length=100)
  public String getLocation() {
    return this.location;
  }

  public void setLocation(String location) {
    this.location = location;
  }

  @Column(length=50)
  public String getLevelCode()
  {
    return this.levelCode;
  }

  public void setLevelCode(String levelCode) {
    this.levelCode = levelCode;
  }
}
以上是实体部分，重点来了，如何将这些数据绑定成List集合呢？看代码

//先查找原数据库
List<Department> equips = theDMO.getObjects("FROM Department");
        System.out.println("原数据库");
        for (Department department : equips) {
            System.out.println(department);
        }
//我们来看看打印的结果：
![这里写图片描述](http://img.blog.csdn.net/20170822095744282?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvdTAxNDI5ODQ0NA==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast)
可以看到原来的数据库是无序的，此时要是导入的话，肯定出错，下面看具体的转换过程

List<Department> resultList=new ArrayList<Department>();
       for (Department department : equips) {  
            if (department.getParent()==null) {//父级菜单开始添加  
                resultList.add(department);  
                if (ifChilds(equips, department.getId())) {//存在子集  
                    List<Department> childs = new ArrayList<>();                             
                    childs = getChildList(equips,department.getId(),childs);  
                    resultList.addAll(childs);  
                  }  
            }  
        }

 //判断是否存在子集  
    private static boolean ifChilds(List<Department> list,String pId) {  
        boolean flag = false;  
        for (Department department : list) {  
           if (department.getParent()!=null) {
               if (department.getParent().getId().equals(pId)) {  
                   flag=true;  
                   break;  
               }  
        } 

        }  
        return flag;  
    }

    //获取父id下的子集合  
    private static List<Department> getChildList(List<Department> list,String pId,List<Department> reList) {  
        for (Department department : list) {  
            if (department.getParent()!=null) {
                 if (department.getParent().getId().equals(pId)) {//查询下级菜单  
                     reList.add(department);  
                     if (ifChilds(list, department.getId())) {  
                         getChildList(list, department.getId(), reList);  
                     }  
                 }  
            }

        }  
        return reList;  
    }
 现在看看转换后的情况吧：

System.out.println(“新数据库”);
for (Department department : resultList) {
if (department.getParent()!=null) {
System.out.println(department.getId()+”\t”+department.getName()+”\t”+department.getParent().getName());

        }else {
            System.out.println(department.getId()+"\t"+department.getName());
             System.out.println("########");
        }

    }       

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Well, we want to help, I was a help to me!