最全的省份递归

递归查询树tree结构有两种做法：

第一种，递归查询数据库结构，

第二种，一次性将数据库表中的所有数据查出来，然后再递归查出来的list集合，

第一种做法适合数据量较少的tree结构，因为要一直查询数据库数据量大时速度回相对较慢，所以数据量大时建议使用第二种方法

public class G {

    public static void main(String[] args) {

        List provinceList = new ArrayList();
        provinceList.add(new Province(0, 1, "陕西"));
        provinceList.add(new Province(1, 2, "延安"));
        provinceList.add(new Province(2, 3, "洛川"));
        provinceList.add(new Province(1, 4, "西安"));
        findAllInProvince(provinceList, 0, "");


    }


    public static class Province {


        private int parent = 0;
        private int children = 0;
        private String info = "";

        public int getParent() {
            return parent;
        }


        public int getChildren() {
            return children;
        }


        public String getInfo() {
            return info;
        }


        public Province(int parent, int children, String info) {
            this.parent = parent;
            this.children = children;
            this.info = info;
        }
    }


    public static void findAllInProvince(List provinceList, int parent, String str) {


        if (parent != 0) {
            str += "----";
        }
        for (int j = 0; provinceList != null && j < provinceList.size(); j++) {
            Province province = (Province) provinceList.get(j);
            Integer children = null;
            if (province != null && province.getParent() == parent) {
                children = province.getChildren();
                System.out.println(str + province.getInfo());
                findAllInProvince(provinceList, children, str);

            }


        }


    }


}

陕西
----延安
--------洛川
----西安