stream流的案例

1. 案例1：

   

    

2. 代码实现;

   import java.util.ArrayList;
   import java.util.Collections;
   import java.util.List;
   import java.util.stream.Collectors;
   
   public class stream案例1 {
       public static void main(String[] args) {
           ArrayList<Integer> list=new ArrayList<>();
           Collections.addAll(list,1,2,3);
           List<Integer> collect = list.stream().filter(s -> s % 2 == 0)
                   .collect(Collectors.toList());
           System.out.println(collect);
       }
   }

3. 案例2：

   

    

4. 案例2代码实现;

   ArrayList<String> LIST=new ArrayList<>();
   Collections.addAll(LIST,"张三,25","李四,24","朝气,26");
   Map<String, Integer> collect = LIST.stream().filter(s -> Integer.parseInt(s.split(",")[1]) >= 25)
           .collect(Collectors.toMap(new Function<String, String>() {
               @Override
               public String apply(String s) {
                   return s.split(",")[0];
               }
           }, new Function<String, Integer>() {
               @Override
               public Integer apply(String s) {
                   return Integer.parseInt(s.split(",")[1]);
               }
           }));
   System.out.println(collect);

   

    

5. 案例3：

   

    

6. 案例3代码实现：

   import java.util.ArrayList;
   import java.util.Collections;
   import java.util.Objects;
   import java.util.function.Function;
   import java.util.stream.Collectors;
   import java.util.stream.Stream;
   
   public class stream案例3 {
       public static void main(String[] args) {
           ArrayList<String> list1=new ArrayList<>();
           ArrayList<String> list2=new ArrayList<>();
           Collections.addAll(list1,"张三,23","李四,24","王五,26");
           Collections.addAll(list1,"杨六,24","杨七,45","zz,26");
           Stream<String> stream1 = list1.stream().filter(s -> s.split(",")[0].length() == 2)
                   .limit(2);
           Stream<String> stream2 = list2.stream().filter(s -> s.split(",")[0]
                   .startsWith("杨")).skip(1);
           Stream.concat(stream1,stream2).map(new Function<String, actor>() {
               @Override
               public actor apply(String s) {
                   String name = s.split(",")[0];
                   int age= Integer.parseInt(s.split(",")[1]);
   
                   return new actor(name,age);
               }
           }).forEach(s-> System.out.println(s));
   
       }
   
   
   
   
   
       }
   
   
   class actor{
       private  String name;
       private  int age;
   
       public actor(String name, int age) {
           this.name = name;
           this.age = age;
       }
   
       public String getName() {
           return name;
       }
   
       public void setName(String name) {
           this.name = name;
       }
   
       public int getAge() {
           return age;
       }
   
       public void setAge(int age) {
           this.age = age;
       }
   
       @Override
       public boolean equals(Object o) {
           if (this == o) return true;
           if (o == null || getClass() != o.getClass()) return false;
           actor actor = (actor) o;
           return age == actor.age &&
                   Objects.equals(name, actor.name);
       }
   
       @Override
       public int hashCode() {
           return Objects.hash(name, age);
       }
   
       @Override
       public String toString() {
           return "actor{" +
                   "name='" + name + '\'' +
                   ", age=" + age +
                   '}';
       }
   }