Java中List集合过滤出符合条件的List元素集合

1. 对基本数据类型的过滤

   List<Integer> list=new ArrayList<>();

   list.add(2);
   list.add(4);
   list.add(20);
   list.add(2130);
   list.add(38);
   //过滤包含2的数据
   list=list.stream().filter(v ->!v.toString().contains("2")).collect(Collectors.toList());
   for (Integer integer : list) {
       System.out.println(integer);
   }

   结果集：

   4 

   38
2. 对Map<String,Object>类型数据进行过滤

   List<Map<String,Object> > list=new ArrayList<>();
   Map<String,Object> map1=new HashMap<>();
   map1.put("sum",3);
   Map<String,Object> map2=new HashMap<>();
   map2.put("age",1);
   map2.put("sum",null);
   list.add(map1);
   list.add(map2);
   //过滤Map中key为sum对应的值为null的数据
   list= list.stream().filter(v ->v.get("sum")!=null).collect(Collectors.toList());
   for (Map<String, Object> map : list) {
       System.out.println(map.get("sum"));
       System.out.println(map.get("age"));
   }

   结果集：

   3
   null
3. 对实体类进行过滤

   List<User> list = new ArrayList<>();
   //数据初始化
   User user = new User();
   user.setAge(10);
   user.setDelFlag(false);
   user.setName("tom");
   user.setPassword("123456");
   User user1 = new User();
   user1.setAge(12);
   user1.setDelFlag(true);
   user1.setName("rose");
   user1.setPassword("123456");
   User user2 = new User();
   user2.setAge(14);
   user2.setDelFlag(false);
   user2.setName("jack");
   user2.setPassword("123456");
   
   list.add(user);
   list.add(user1);
   list.add(user2);
   //保留未删除和年龄大于10的用户对象
   list = list.stream().filter(obj -> obj.getDelFlag() == false && obj.getAge() > 10).collect(Collectors.toList());
   for (User user3 : list) {
       System.out.println(user2);
   }

   class User {
       private String name;
       private Boolean delFlag;
       private Integer age;
       private String password;

       @Override
       public String toString() {
           return "User{" +
              "name='" + name + '\'' +
              ", delFlag=" + delFlag +
              ", age=" + age +
              ", password='" + password + '\'' +
              '}';
       }

       public String getName() {
           return name;
       }
   
       public void setName(String name) {
           this.name = name;
       }
   
       public Boolean getDelFlag() {
           return delFlag;
       }
   
       public void setDelFlag(Boolean delFlag) {
           this.delFlag = delFlag;
       }
   
       public Integer getAge() {
           return age;
       }
   
       public void setAge(Integer age) {
           this.age = age;
       }
   
       public String getPassword() {
           return password;
       }
   
       public void setPassword(String password) {
           this.password = password;
       }
   结果集
   User{name='jack', delFlag=false, age=14, password='123456'}