Stream系列（二）Map方法使用

Stream 将List转换成新的List 对象

EmployeeTestCase.java

package com.example.demo;

import lombok.Data;
import lombok.ToString;
import lombok.extern.log4j.Log4j2;
import org.junit.Test;

import java.util.List;
import java.util.stream.Collectors;

@Log4j2
public class EmployeeTestCase extends BaseTest{

    @Test
    public void map(){
        List<Leader> leaders = list.stream().filter(employee -> employee.getSalary() == 2000).map(employee -> {
            Leader leader = new Leader();
            leader.setName(employee.getName());
            leader.setSalary(employee.getSalary());
            return leader;
        }).peek(System.out::println).collect(Collectors.toList());
    }
    @Data
    @ToString
    class Leader{
        private String name;
        private double salary;
    }

}

BaseTest.java

package com.example.demo;

import java.util.Arrays;
import java.util.List;

public class BaseTest {
    protected static final List<Employee> list = Arrays.asList(
            new Employee(1, "Alex", 1000),
            new Employee(2, "Michael", 2000),
            new Employee(3, "Jack", 1500),
            new Employee(4, "Owen", 1500),
            new Employee(5, "Denny", 2000));

    protected static final List<List<Employee>> listFlat = Arrays.asList(
            Arrays.asList(new Employee(1, "Alex", 1000),
                          new Employee(2, "Michael", 2000)),
            Arrays.asList(new Employee(3, "Jack", 1500),
                          new Employee(4, "Owen", 1500)),
            Arrays.asList(new Employee(5, "Denny", 2000)));
}