Java Lambda 表达式以及对 Lambda 表达式的简化

LambdaDemo.java

package com.zhong.lambdademo;import java.util.Arrays;
import java.util.Comparator;public class LambdaDemo {public static void main(String[] args) {Student[] student = new Student[5];student[0] = new Student("小钟", 179.1, 22);student[1] = new Student("小王", 152.1, 21);student[2] = new Student("小张", 199.2, 32);student[3] = new Student("小红", 120.8, 92);student[4] = new Student("小芳", 169.3, 54);// 1.原始排序Arrays.sort(student, new Comparator<Student>() {@Overridepublic int compare(Student o1, Student o2) {// return o2.age-o1.age;   降序return o1.getAge() - o2.getAge();}});// lambda 表达式Arrays.sort(student, (o1, o2) -> o2.getAge() - o1.getAge());// 静态方法引用Arrays.sort(student, CompareByData::CompareByAge);// 实例方法引用CompareByData compareByData = new CompareByData();Arrays.sort(student, compareByData::CompareByAge2);for (Student stu : student) {System.out.println(stu);}String[] names = {"body", "angela", "Andy", "deli", "caoCao", "BaBo", "jack", "jk"};// 忽略首字符大小写排序Arrays.sort(names, new Comparator<String>() {@Overridepublic int compare(String o1, String o2) {return o1.compareToIgnoreCase(o2);}});// 特定类型方法引用简化Arrays.sort(names, String::compareToIgnoreCase);System.out.println(Arrays.toString(names));// 构造器引用CreateStudent createStudent = new CreateStudent() {@Overridepublic Student Create(String name, Double height, int age) {return new Student(name, height, age);}};Student createStu = createStudent.Create("小钟", 179.1, 22);System.out.println(createStu);// lambda 简化CreateStudent createStudent1 = (name, height, age) -> new Student(name, height, age);Student createStu1 = createStudent1.Create("小王", 152.1, 21);System.out.println(createStu1);// 构造器引用简化CreateStudent createStudent2=  Student::new;Student createStu2 = createStudent2.Create("小红", 120.8, 92);System.out.println(createStu2);}
}interface CreateStudent {Student Create(String name, Double height, int age);
}

CompareByData.java

package com.zhong.lambdademo;public class CompareByData {public static int CompareByAge(Student o1, Student o2) {return o2.getAge() - o1.getAge();}public int CompareByAge2(Student o1, Student o2) {return o2.getAge() - o1.getAge();}
}

Student .java

package com.zhong.lambdademo;public class Student {private String name;private Double height;private int age;public Student() {}public Student(String name, Double height, int age) {this.name = name;this.height = height;this.age = age;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Double getHeight() {return height;}public void setHeight(Double height) {this.height = height;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}@Overridepublic String toString() {return "Student{" +"name='" + name + '\'' +", height=" + height +", age=" + age +'}';}
}