Stream filter和groupby例子

Set<String> type = new HashSet<String>();
type.add("1");
type.add("2");
type.add("3");
type.add("4");

BU_MAP_SECTION = sectionNodes.stream().filter(item -> {
    Integer parentid = item.getParentid();
    boolean isParent_1 = parentid.equals(new Integer("-1"));
    String depttypecode = item.getDepttypecode();
    boolean isContain = type.contains(depttypecode);
    if (isParent_1 && isContain) {
        return true;
    }
    return false;
}).collect(Collectors.groupingBy(item->{
    return item.getBureaucode();
}));

//BU_MAP_SECTION = sectionNodes.stream().collect(Collectors.groupingBy(Jcdept::getBureaucode));