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)));

}
`