java8判断list＜Map＜String,Object＞＞ 对象某个属性的值是否重复

java8判断list> 对象某个属性的值是否重复

	List> list = new ArrayList<>();
        Map m1 = new HashMap<>();
        m1.put("a","1");
        m1.put("b","z");
        Map m2 = new HashMap<>();
        m2.put("a","1");
        m2.put("b","y");
        Map m3 = new HashMap<>();
        m3.put("a","2");
        m3.put("b","j");
        list.add(m1);
        list.add(m2);
        list.add(m3);
        Map collect2 = list.stream().collect(
                Collectors.groupingBy( map -> MapUtils.getMapStrdef(ma