*/@TestpublicvoidmapTest(){//获取用户列表List<User>userList=UserService.getUserList();//获取用户名称列表List<String>nameList=userList.stream().map(User::getName).collect(Collectors.toList());//或者:List<String> nameList = userList.stream().map(user -> user.getName()).collect(Collectors....
Java8使用stream对List列表分组 定义实体类public class Person { public Integer id; public String name; public Integer age; public Person(){} public Person(Integer id, Integer age, String name){ this.id = id; this.age = age; this.name = name; } @Override public String toString(){ return...
List<UserPO> userList = getUserList(); //根据部门和性别对用户列表进行分组 Map<String,Map<String,List<UserPO>>> userMap = userList.stream().collect(Collectors.groupingBy(UserPO::getDepartment,Collectors.groupingBy(UserPO::getSex))); //遍历分组后的结果 userMap.forEach((key1, map) -> {...
boolean result1 = userList.stream().anyMatch(user -> user.getName().equals("pan_junbiao的博客_01")); //判断用户名称是否都包含“pan_junbiao的博客”字段 boolean result2 = userList.stream().allMatch(user -> user.getName().contains("pan_junbiao的博客")); //判断用户名称是否存在不包含“pa...
当然,以下是一个使用Java 8 Stream API对List中的元素进行分组并统计的示例。假设我们有一个Transaction类,其中包含属性category、subCategory和amount,我们想要按category和subCategory分组并对每个组内的amount求和。 import java.util.*; import java.util.stream.*; ...
* 使用java8 stream groupingBy操作,按城市分组list并计算分组销售平均值 */@TestpublicvoidgroupingByAverageTest(){Map<String,Double>employeesByCity=employees.stream().collect(Collectors.groupingBy(Employee::getCity,Collectors.averagingInt(Employee::getSales)));System.out.println(employeesByCity);assertEquals(emp...
public static void main(String[] args) {Optional<Student> collect1 = students.stream().collect(Collectors.maxBy((s1, s2) -> s1.getAge() - s2.getAge())); Optional<Student> collect2 = students.stream().collect(Collectors.minBy((s1, s2) -> s1.getAge() - s2.getAge())); ...
Map<String,Integer>mapSum=excelDtoList.stream().collect(Collectors.groupingBy(Name::getNameCode,Collectors.summingInt(Name::getSum)));mapSum.forEach((s,integer)->{System.out.print(s+":");System.out.println(integer);});System.out.println("---list去重---");//对象去重List<Name>distinctLis...
Java8使用stream对List列表分组 Java8使⽤stream对List列表分组 1. 定义实体类 public class Person { public Integer id;public String name;public Integer age;public Person(){} public Person(Integer id, Integer age, String name){ this.id = id;this.age = age;this.name = name;} @Override publ...