利用jdk8的新特性將一個對象集合轉化為其他對象集合的方式

1　　以下代碼主要利用jdk8中的lambda表達式, 和集合的stream()流 

 

2　　建立Person類和Student類,student繼承Person

package demo;

public class Person {
    private String name;
    private Long pId;

    public Person() {
    }

    public Person(String name, Long pId) {
        this.name = name;
        this.pId = pId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Long getpId() {
        return pId;
    }

    public void setpId(Long pId) {
        this.pId = pId;
    }
}

package demo;

public class Student extends Person {
    private String schoolName;
    private Long sId;

    public String getSchoolName() {
        return schoolName;
    }

    public void setSchoolName(String schoolName) {
        this.schoolName = schoolName;
    }

    public Long getsId() {
        return sId;
    }

    public void setsId(Long sId) {
        this.sId = sId;
    }
    @Override
    public String toString() {
        return  this.getName()+"-"+this.getpId()+"-"+this.getSchoolName()+"-"+this.getsId();
    }
}


3　　建立主函數,測試

package demo;

import org.springframework.beans.BeanUtils;

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

public class demo {
    public static void main(String[] args) {

        List<Person> persons = Arrays.asList(
                new Person("張三", 1L),
                new Person("李四", 2L)
        );
 //        將Peson集合轉化為String集合

        List<String> strs=persons.stream().map(person -> person.getName()).collect(Collectors.toList());

        System.out.println("strs = " + strs);

//        將Person集合轉化為Student集合

        List<Student> students = persons.stream().map(person -> {
            Student student = new Student();
            BeanUtils.copyProperties(person, student);
            if (person.getName() == "張三") {
                student.setSchoolName("三中");
                student.setsId(3L);
            }
            if (person.getName() == "李四") {
                student.setSchoolName("四中");
                student.setsId(4L);
            }
            return student;
        }).collect(Collectors.toList());
        System.out.println("students = " + students);

    }
}