stream流对List<Map<String,String>>某个字段去重

你好，关于你的问题，可以使用Java 8中的stream流的distinct()方法对List<Map<String,String>>某个字段进行去重。具体代码演示可以参考以下示例：

List<Map<String,String>> list = new ArrayList<>();
list.add(new HashMap<String,String>(){{put("id","1"); put("name","John");}});
list.add(new HashMap<String,String>(){{put("id","2"); put("name","Peter");}});
list.add(new HashMap<String,String>(){{put("id","3"); put("name","John");}});
list.add(new HashMap<String,String>(){{put("id","4"); put("name","Mary");}});

List<Map<String,String>> distinctList = list.stream().filter(
    distinctByKey(map -> map.get("name"))
).collect(Collectors.toList());

System.out.println(distinctList);
// Output: [{id=1, name=John}, {id=2, name=Peter}, {id=4, name=Mary}]

public static <T> Predicate<T> distinctByKey(Function<? super T, Object> keyExtractor) {
    Map<Object, Boolean> seen = new ConcurrentHashMap<>();
    return t -> seen.putIfAbsent(keyExtractor.apply(t), Boolean.TRUE) == null;
}

希望能帮到你，如果你有其他问题可以继续提出。