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lamda 表達式

方法 void util dal awr player 對象 lan main

// 新建 Person類 用於測試的數據源

public class Person {

  private String firstName;

  private String lastName;

  private String job;

  private String gender;
  private int salary;

  private int age ;

  public Person(String firstName, String lastName, String job,
    String gender, int age, int salary) {
    this.firstName = firstName;
    this.lastName = lastName;
    this.gender = gender;
    this.age = age;
    this.job = job;
    this.salary = salary;
  }

  public String getFirstName() {
    return firstName;
  }

  public void setFirstName(String firstName) {
    this.firstName = firstName;
  }

  public String getLastName() {
    return lastName;
  }

  public void setLastName(String lastName) {
    this.lastName = lastName;
  }

  public String getJob() {
    return job;
  }

  public void setJob(String job) {
    this.job = job;
  }

  public String getGender() {
    return gender;
  }

  public void setGender(String gender) {
    this.gender = gender;
  }

  public int getSalary() {
    return salary;
  }

  public void setSalary(int salary) {
    this.salary = salary;
  }

  public int getAge() {
    return age;
  }

  public void setAge(int age) {
    this.age = age;
  }
}

// 測試類

import java.util.*;
import java.util.function.Consumer;
import java.util.stream.Collectors;

public class Streams {  

  // 1. 不需要參數,返回值為 5
  // () -> 5
  //  
  // 2. 接收一個參數(數字類型),返回其2倍的值
  // x -> 2 * x
  //
  // 3. 接受2個參數(數字),並返回他們的差值
  // (x, y) -> x – y
  //
  // 4. 接收2個int型整數,返回他們的和
  // (int x, int y) -> x + y
  //
  // 5. 接受一個 string 對象,並在控制臺打印,不返回任何值(看起來像是返回void)
  // (String s) -> System.out.print(s)

  

  public void calc(){ //新建集合 做一個簡單的排序輸出
    List<Integer> list =new ArrayList<>();
    list.add(1);
    list.add(23);
    list.add(88);
    list.add(26);
    list.add(64);   

    Collections.sort(list, (x, y) -> y - x);
    list.forEach((aa)->System.out.print(aa+" ")); // 第一種輸出方式
    list.forEach(System.out::println); // 第二種輸出方式

  }

    // 第一個測試

  //public static void main(String[] args) { // 運行測試一下calc() 方法
  //  new Streams().calc();
  //}

    // 第二個測試

  //public static void main(String[] args) {
  //  String[] players = {"Rafael Nadal", "Novak Djokovic",
  //           "Stanislas Wawrinka", "David Ferrer",
  //           "Roger Federer", "Andy Murray",
  //           "Tomas Berdych", "Juan Martin Del Potro",
  //           "Richard Gasquet", "John Isner"}; // 定義一個數組 進行排序 然後輸出
  //
  //  Arrays.sort(players, (String s1, String s2) -> (s1.compareTo(s2))); // 對數組 進行 排序
  //  List<String> lists = Arrays.asList(players); // 把排序後的數組 轉為集合
  //  lists.forEach((play)->System.out.println(play)); // 輸出集合內容
  //}

    // 第三個測試

  //public static void main(String[] args) {

    //List<Person> programmers = new ArrayList<Person>() {  // 定義一個  List 集合
    //  add(new Person("Jarrod", "Pace", "PHP programmer", "male", 34, 1550));
    //  add(new Person("Clarette","Cicely" , "PHP programmer", "female",23 , 1200));
    //  add(new Person("Victor", "Channing","PHP programmer" ,"male" , 32, 1600));
    //  add(new Person("Tori", "Sheryl", "PHP programmer" ,"female",21 ,1000 ));
    //  add(new Person("Osborne", "Shad", "PHP programmer", "male", 32, 1100));
    //  add(new Person("Rosalind","Layla" , "PHP programmer", "female",25 , 1300));
    //  add(new Person("Fraser", "Hewie", "PHP programmer", "male", 36, 1100));
    //  add(new Person("Quinn", "Tamara", "PHP programmer", "female",21 , 1000));
    //  add(new Person("Alvin", "Lance", "PHP programmer", "male", 38, 1600));
    //  add(new Person("Evonne", "Shari", "PHP programmer", "female",40 , 1800));
    //  add(new Person("Jack", "Tgasd", "PHP programmer", "female",42 , 1600));
    //  add(new Person("Rose", "Ebacr", "PHP programmer", "female",36 , 1600));
    //  add(new Person("Smith", "Ftaaw", "PHP programmer", "female",21 , 1600));
    //  add(new Person("Dove", "Drace", "PHP programmer", "female",19 , 1600));
    //  add(new Person("Lamda", "Amabg", "PHP programmer", "female",53 , 1600));
    //  add(new Person("Grails", "Bhacy", "PHP programmer", "female",42 , 1600));
    //};

    
    // System.out.println("下面是月薪超過 1400人員 :");
    // programmers.stream()
    // .filter((p) -> (p.getSalary() > 1400)) // 過濾 薪資大於1400 的所有人員
    // .forEach((p) -> System.out.printf("%s-%s; ", p.getFirstName(), p.getLastName()));

    

    // System.out.println();
    // System.out.println("下面是月薪等於 1000 的人員:");
    // programmers.stream()
    //.filter((p) -> ("Osborne".equals(p.getFirstName()))) // // 過濾 姓 是Osborne
    //.forEach((p) -> System.out.println(p.getFirstName()+p.getLastName()));

    

    //System.out.println();
    //System.out.println("工資等於 $1600的人員 按年齡排序:默認 從大到小");
    //List<Person> pg = programmers .stream().filter(pgs -> 1600==pgs.getSalary())

   //.sorted((aud1,aud2) -> aud2.getAge().compareTo(aud1.getAge())) // 1、比較函數 進行排序

        // 2、比較函數前加負號可降序排列 .sorted((aud1,aud2) -> -(aud2.getAge().compareTo(aud1.getAge())))
    //.collect(Collectors.toList());
    //pg.forEach((p) -> System.out.println(p.getFirstName()+"-"+p.getLastName()+" "+p.getSalary()+" "+p.getAge()));

  //}

}

lamda 表達式