java8 按条件过滤集合

//黄色部分为过滤条件
list.stream().filter(user-> user.getId() > 5 && "1组".equals(user.group)).collect(Collectors.toList());

示例：

public class HelloWorld {public static void main(String[] args) {Random random = new Random();List<User> list = new ArrayList<>();for(int i=1;i<=20;i++) {String group = (random.nextInt(3) + 1) + "组";//1-3组随机User u = new User(i, "用户-" + i, group);list.add(u);}System.out.println("过滤前：" + list);//按条件过滤List<User> filterList = list.stream().filter(user -> user.getId() > 5 && "1组".equals(user.group)).collect(Collectors.toList());System.out.println("过滤 后：" + filterList);}private static class User{Integer id;String name;String group;public User(Integer id, String name, String group) {this.id = id;this.name = name;this.group = group;}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getGroup() {return group;}public void setGroup(String group) {this.group = group;}@Overridepublic String toString() {return "User{" +"id=" + id +", name='" + name + '\'' +", group='" + group + '\'' +'}';}}}

执行结果：

过滤前：[User{id=1, name='用户-1', group='2组'}, User{id=2, name='用户-2', group='1组'}, User{id=3, name='用户-3', group='2组'}, User{id=4, name='用户-4', group='2组'}, User{id=5, name='用户-5', group='3组'}, User{id=6, name='用户-6', group='1组'}, User{id=7, name='用户-7', group='3组'}, User{id=8, name='用户-8', group='2组'}, User{id=9, name='用户-9', group='1组'}, User{id=10, name='用户-10', group='1组'}, User{id=11, name='用户-11', group='2组'}, User{id=12, name='用户-12', group='2组'}, User{id=13, name='用户-13', group='2组'}, User{id=14, name='用户-14', group='2组'}, User{id=15, name='用户-15', group='2组'}, User{id=16, name='用户-16', group='3组'}, User{id=17, name='用户-17', group='1组'}, User{id=18, name='用户-18', group='1组'}, User{id=19, name='用户-19', group='1组'}, User{id=20, name='用户-20', group='3组'}]
过滤 后：[User{id=6, name='用户-6', group='1组'}, User{id=9, name='用户-9', group='1组'}, User{id=10, name='用户-10', group='1组'}, User{id=17, name='用户-17', group='1组'}, User{id=18, name='用户-18', group='1组'}, User{id=19, name='用户-19', group='1组'}]