Java - Stream Filter 多条件筛选过滤

清疚 2024-03-16 13:12 21阅读 0赞

Java Stream流中Filter用于通过设置的条件过滤出元素 ，示例如下：

List strings = Arrays.asList(“abc”, “”, “bc”, “efg”, “abcd”,"", “jkl”);
    
    List filtered = strings.stream().filter(string -> !string.isEmpty()).collect(Collectors.toList());

如果需要进行多条件过滤

我们可以对这些参数进行处理，我们只是需要做一下判断，即：

让所有参数默认为 false，然后对传进来的值进行取值判断，若满足该条件为true，多个条件进行多次判断

判断完成之后 会拿到所有的boolean值 通过 && 拼接返回，即 有一个为false，即返回值为false

通过该方法会对一个对象进行多条件过滤

public static List<BidListVo> checkOperationv1(List<BidListVo> list, BidProgressEnum progressEnum){
            Integer progress = Integer.valueOf(progressEnum.getCode());
            String nodeId = progressEnum.getNode();
            List<BidListVo> collect = list.stream().filter(bidListVo -> filterProgress(bidListVo,progress)  )
                    .collect(Collectors.toList());
         
            return collect;
        }
    
        private static boolean filterProgress(BidListVo bidListVo, Integer progress) {
            //副流程未开始 只判断主流程
            if(StringUtils.isEmpty(bidListVo.getReviewProgress())){
                return Integer.valueOf(bidListVo.getProgress()) >= progress ? true: false;
            }else if(Integer.valueOf(bidListVo.getProgress()) >= progress ||
                    Integer.valueOf(bidListVo.getReviewProgress()) >= progress){
                // 主流程 独立流程 任意一个大于当前筛选进度就好
                return true;
            }
            return false;
        }

示例

public class MultiFilterTest {
        public static void main(String[] args) {
            List<User> userList = getUserList();
    
            // 筛选 age > 18 && address = "上海" 的user
            List<User> filterList = userList.stream().filter(user -> filterAgeAndAddress(user,18,"上海")).collect(Collectors.toList());
    
            filterList.forEach(System.out::println);
        }
    
        // 筛选 age > 18 && address = "上海" 的user
        private static boolean filterAgeAndAddress(User user,Integer age,String address){
    
            if(user.getAge() > 18 && address.equals(user.getAddress())){
                return true;
            }
            return false;
        }
    
        private static List<User> getUserList() {
            List<User> userList = new ArrayList<>();
    
            userList.add(new User(1,"张三",18,"上海"));
            userList.add(new User(2,"王五",16,"上海"));
            userList.add(new User(3,"李四",20,"上海"));
            userList.add(new User(4,"张雷",22,"北京"));
            userList.add(new User(5,"张超",15,"深圳"));
            userList.add(new User(6,"李雷",24,"北京"));
            userList.add(new User(7,"王爷",21,"上海"));
            userList.add(new User(8,"张三丰",18,"广州"));
            userList.add(new User(9,"赵六",16,"广州"));
            userList.add(new User(10,"赵无极",26,"深圳"));
    
            return userList;
        }
    }

输出如下：

![c96d2f2efd904f178a3156c13f5e6eb1.png][]

[c96d2f2efd904f178a3156c13f5e6eb1.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/16/fcadfbdacec5401fa5f9e856e4c3a126.png