java 将数据字典（父子结构）绑定成List集合

java 将数据字典（父子结构）绑定成List集合，以实现数据库同步功能
最近公司做了一个项目，其中有一个功能是将本地的数据库同步到远程服务器端，同步的过程不是本文章的重点，重点是在导入的过程中，涉及到一个数据字典类型的表，也就是带有父ID的表，即（父子表），这就对导入提出了新的要求：就是在导入新的表中时，必须先导入父表，再导入子表，如果多级的话，依次从顶级开始向下导入，领导和我说了一顿，什么while循环啊，递归啊，说实话，我知道他要表达的意思，可就是不会写，没办法上网找找，终于我看到了一偏文章：

Kaer_GG的文章，树形list（菜单树）递归遍历list对我帮助很大，好了，不费话，看看我的数据库结构：
，好了，接下来把相对应的实体给大家看看

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("########");        }    }       

“`

好了，希望对大家有所帮助，对我自己也是个帮助！