Guava总结4-杂七杂八

Splitter 和 Joiner

一个是自动分割,一个是合并.直接看代码

//用逗号隔开.
private static final String SPLITE = ",";

    private static final Joiner joiner = Joiner.on(SPLITE);

    private static final Splitter splitter = Splitter.on(SPLITE);

public void join(){
//将list自动变成以逗号分割组成的字符串
lotteryAwardMsgDO.setJuids(joiner.join(lotteryAwardMsgBO.getJuidList()));
}

public void splite{
//把一个字符串用逗号分隔开,然后自动转换成Iterable<String>
for(String juidStr: splitter.trimResults().omitEmptyStrings().split(lotteryAwardMsgDO.getJuids())){
            if(isNumeric(juidStr)){
                lotteryAwardMsgBO.addJuId(Long.parseLong(juidStr));
            }
        }
}
//比如 一个字符串是 “key1_value1:key2_value2”,可以这样
Map<String,String> map = Splitter.on(":").trimResults().withKeyValueSeparator("_").split("key1_value1:key2_value2");

 

 

列表的自动类型转换

比如将List<String> 类型转换成List<Long>

直接看例子.

@Override
        public List<BackCatClientTO> getChildren() {
            List<BackCategoryTO> children = backCategoryForest.getChildBackCats().get(categoryId);
            if(children == null || children.isEmpty()) return Collections.EMPTY_LIST;
            List<Long> categoryIds = Lists.transform(children,new Function<BackCategoryTO, Long>() {
                @Nullable
                @Override
                public Long apply(@Nullable BackCategoryTO backCategoryTO) {
                    return backCategoryTO.getCategory();
                }
            });
            return BackCatClientServiceImpl.this.build(categoryIds);
        }

 

筛选

比如某一个List中,把一些不符合要求的数据给筛选掉,直接看例子

注意,这个方法是非线程安全的.

Iterables.removeIf(frontCats, new Predicate<JuCategoryTO>() {
				@Override
				public boolean apply(@Nullable JuCategoryTO input) {
					return input.isHidden();
				}
			});

 

排序

直接看代码

Collections.sort(juCategoryTOs,new Comparator<JuCategoryTO>() {
            @Override
            public int compare(JuCategoryTO o1, JuCategoryTO o2) {
                //大的返回1,小的返回-1 .
                if(o1.getIndex() > o2.getIndex()){
                    return 1;
                } else if(o1.getIndex() < o2.getIndex()){
                    return -1;
                }else {
                    return 0;
                }
            }
        });

 双向map

public class VisitTypeMachine {

    private static final  BiMap<Integer,String> visitType2Name = HashBiMap.create();

    static {
        visitType2Name.put(1,"淘宝类目");
        visitType2Name.put(2,"直接访问");
        visitType2Name.put(3,"淘宝搜索");
        visitType2Name.put(4,"淘宝站内其他");
        visitType2Name.put(5,"店内浏览");
        visitType2Name.put(6,"QQ空间");
        visitType2Name.put(7,"阿里旺旺非广告");
        visitType2Name.put(8,"店铺收藏");
        visitType2Name.put(9,"购物车");
        visitType2Name.put(10,"淘宝客");
        visitType2Name.put(11,"淘宝站外其他");
        visitType2Name.put(12,"我的淘宝");
        visitType2Name.put(13,"直通车");
        visitType2Name.put(99,"未纳入");

    }

    public static String getNameByType(Integer type){
        return visitType2Name.get(type);
    }

    public static Integer getTypeByName(String name){
        Integer integer = visitType2Name.inverse().get(name);
        return integer;
    }
}

 

TreeRangeMap

经常会有一些需求，比如 0到60分是不及格，60到85分是良 85到100是优。如果不想写一堆if else 就可以试试用 TreeRangeMap

hashRangeMap = TreeRangeMap.create(); 
            hashRangeMap.put(Range.atMost(83268L), 0);
            hashRangeMap.put(Range.openClosed(83268L, 1998816L), 1);
            hashRangeMap.put(Range.openClosed(1998816L, 170404392L), 10);
            hashRangeMap.put(Range.openClosed(170404392L, 5899180011L), 100);
            hashRangeMap.put(Range.openClosed(5899180011L, 8184000062L), 300);
            hashRangeMap.put(Range.openClosed(8184000062L, 43657112106L), 700);
            hashRangeMap.put(Range.openClosed(43657112106L, 136910372737L), 1500);
            hashRangeMap.put(Range.openClosed(136910372737L, 698513762858L), 4000);
            hashRangeMap.put(Range.openClosed(698513762858L, 1396960220484L), 6000);
            hashRangeMap.put(Range.greaterThan(1396960220484L), 8000);