Stream与递归使用
作者:互联网
(一)Stream 好用
@Override
public List<CategoryEntity> listWithTree() {
//1 查出所有分类
List<CategoryEntity> categoryEntities = baseMapper.selectList(null);
//2 组装成父子的树形结构
//2.1 找到所有一级分类
List<CategoryEntity> level1Menus = categoryEntities.stream().filter((categoryEntitie) -> {
return categoryEntitie.getParentCid() == 0;
}).map(menu -> {
menu.setChildren(getChildrens(menu,categoryEntities));
return menu;
}).sorted((menu1,menu2) -> {
return (menu1.getSort() == null ? 0 : menu1.getSort()) - (menu2.getSort() == null ? 0 : menu2.getSort());
}).collect(Collectors.toList());
return level1Menus;
}
private List<CategoryEntity> getChildrens(CategoryEntity root,List<CategoryEntity> all){
List<CategoryEntity> children = all.stream().filter(categoryEntity -> {
return categoryEntity.getParentCid() == root.getCatId();
}).map((categoryEntity) -> {
//找子菜单 递归
categoryEntity.setChildren(getChildrens(categoryEntity, all));
return categoryEntity;
}).sorted((menu1, menu2) -> {
//排序
return (menu1.getSort() == null ? 0 : menu1.getSort()) - (menu2.getSort() == null ? 0 : menu2.getSort());
}).collect(Collectors.toList());
return children;
}
我看过沙漠下暴雨
标签:return,Stream,递归,List,categoryEntity,menu2,menu1,使用,getSort 来源: https://www.cnblogs.com/misscai/p/12776006.html