关于递归查询子节点

J2EE_ME 2014-05-26 12:08:58

又遇到这种问题了，求教。

我有一个class是这样

public class GeographicalArea {

private String name;
private ArrayList<GeographicalArea> subAreas; ／／这是子结点
private ArrayList<GeographicalArea> containedBy; ／／这是父节点

。。。。。。

public GeographicalArea[] getAreayWithSubarea()｛

／／我要在这里实现返回所有的子节点
｝
｝

求助。。多谢

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vnvlyp 2014-05-26

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昨天你才问的父节点吧。。今天又问子节点。。你倒是自己思考一下啊，这么基本的问题任何一本关于这个的书都基本能讲得很明白了

J2EE_ME 2014-05-26

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还是感谢你的热心帮助。结帖了。

引用 4 楼 vnvlyp 的回复:

	public GeographicalArea[] getAreaWithSubarea() {
		ArrayList<GeographicalArea> list = this.getSubarea();
		GeographicalArea[] areas = new GeographicalArea[list.size()];
		int i = 0;
		for (GeographicalArea area : list) {
			areas[i++] = area;
		}
		return areas;
	}
	
	private ArrayList<GeographicalArea> getSubarea() {
		ArrayList<GeographicalArea> areas = new ArrayList<>();
		for (GeographicalArea area : this.subAreas) {
			areas.add(area);
			areas.addAll(area.getSubarea());
		}
		return areas;
	}

J2EE_ME 2014-05-26

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private List<GeographicalArea> areaArray = new ArrayList<GeographicalArea>();
public void recursionFn(GeographicalArea area){
if(area.getSubAreas()!=null && area.getSubAreas().size() >0){
areaArray.add(area);
Iterator<GeographicalArea> childIT = area.getSubAreas().iterator();
while(childIT.hasNext()){
GeographicalArea node = (GeographicalArea)childIT.next();
recursionFn(node);
}
}else{
areaArray.add(area);
}

}

调整格式为java，方便大家看。

J2EE_ME 2014-05-26

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我最后这么解决了。我没有办法把结果写进array 里，因为这个方法会被递归调用很多次，所以我重新写了一个class来递归。贴出来： private List<GeographicalArea> areaArray = new ArrayList<GeographicalArea>(); public void recursionFn(GeographicalArea area){ if(area.getSubAreas()!=null && area.getSubAreas().size() >0){ areaArray.add(area); Iterator<GeographicalArea> childIT = area.getSubAreas().iterator(); while(childIT.hasNext()){ GeographicalArea node = (GeographicalArea)childIT.next(); recursionFn(node); } }else{ areaArray.add(area); } }

引用 4 楼 vnvlyp 的回复:

	public GeographicalArea[] getAreaWithSubarea() {
		ArrayList<GeographicalArea> list = this.getSubarea();
		GeographicalArea[] areas = new GeographicalArea[list.size()];
		int i = 0;
		for (GeographicalArea area : list) {
			areas[i++] = area;
		}
		return areas;
	}
	
	private ArrayList<GeographicalArea> getSubarea() {
		ArrayList<GeographicalArea> areas = new ArrayList<>();
		for (GeographicalArea area : this.subAreas) {
			areas.add(area);
			areas.addAll(area.getSubarea());
		}
		return areas;
	}

vnvlyp 2014-05-26

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	public GeographicalArea[] getAreaWithSubarea() {
		ArrayList<GeographicalArea> list = this.getSubarea();
		GeographicalArea[] areas = new GeographicalArea[list.size()];
		int i = 0;
		for (GeographicalArea area : list) {
			areas[i++] = area;
		}
		return areas;
	}
	
	private ArrayList<GeographicalArea> getSubarea() {
		ArrayList<GeographicalArea> areas = new ArrayList<>();
		for (GeographicalArea area : this.subAreas) {
			areas.add(area);
			areas.addAll(area.getSubarea());
		}
		return areas;
	}

J2EE_ME 2014-05-26