java比较器 之compareable 和comparato比较
compareable
测试类
import java.util.Set;
import java.util.TreeSet; public class Test { public static void main(String[] args) {
Set<Person>allset = new TreeSet<Person>();
allset.add(new Person(22,"hjw",20000.0,"论语",50.0));
allset.add(new Person(22,"fyy",7000.0,"大学",40.0));
allset.add(new Person(22,"hjl",6000.0,"孟子",30.0));
allset.add(new Person(22,"hlq",10000.0,"中庸",20.0));
allset.add(new Person(24, "hsx", 20000.0,"诗经", 40.0));
allset.add(new Person(22,"cl",20000.0,"离骚",10.0));
allset.add(new Person(22,"zsk",20000.0,"墨子",25.0));
allset.add(new Person(22,"hjw",20000.0,"论语",23.0));
allset.add(new Person(22,"hjw",20000.0,"论语",22.0));
System.out.println(allset);
} }
person类
public class Person extends Book implements Comparable<Person> {
private Integer age;
private String name;
private Double salary;
//private String book;
public Integer getAge() {
return age;
}
public Person(Integer age, String name, Double salary,String bookname, double price) {
super(bookname, price);
this.age = age;
this.name = name;
this.salary = salary;
//this.book = book;
}
public void setAge(Integer age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Double getSalary() {
return salary;
}
public void setSalary(double salary) {
this.salary = salary;
}
@Override
public int compareTo(Person o) { if (this.salary>o.salary) {
return -1;
}
else if(this.salary<o.salary){
return 1;
}
else
{
if (this.age>o.age){
return 1;
}else if(this.age<o.age){
return -1;
}else{
if (this.name!=o.name) {
return this.name.compareTo(o.name);
}else {
if(this.price>o.price){
return 1;
}else if(this.price<o.price){
return -1;
}else {
return this.bookname.compareTo(o.bookname);
}
}
}
}
}
@Override
public String toString() {
return "Person [age=" + age + ", name=" + name + ", salary=" + salary + ", bookname=" + bookname + ", price="
+ price + "]";
} }
Book类
public class Book {
public String bookname;
public Double price; public Book(String bookname, double price) { this.bookname = bookname;
this.price = price;
}
public String getBookname() {
return bookname;
}
public void setBookname(String bookname) {
this.bookname = bookname;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
@Override
public String toString() {
return "Book [bookname=" + bookname + ", price=" + price + "]";
} }
自定义比较器Comparator类
Book类
public class Book {
public String bookname;
public Double price;
public Book(){}
public Book(String bookname, double price) { this.bookname = bookname;
this.price = price;
}
public String getBookname() {
return bookname;
}
public void setBookname(String bookname) {
this.bookname = bookname;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
@Override
public String toString() {
return "Book [bookname=" + bookname + ", price=" + price + "]";
} }
Person类
public class Person {
private Integer age;
private String name;
private double salary;
private Book book;
public Person(Integer age, String name, double salary,String bookname, double price) { this.age = age;
this.name = name;
this.salary = salary;
this.book=new Book(bookname,price); }
public Integer getAge() {return age;}
public void setAge(Integer age) {
this.age = age;
}
public Book getBook() {
return book;
}
public void setBook(Book book) {
this.book = book;
}
public void setSalary(double salary) {
this.salary = salary;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getSalary() {
return salary;
} @Override
public String toString() {
return "Person [age=" + age + ", name=" + name + ", salary=" + salary + ", book=" + book + "]";
} }
自定义Comparator类
import java.util.Comparator; public class SalaryCom implements Comparator<Person>{ @Override
public int compare(Person o1, Person o2) {
if(o1.getSalary()!=o2.getSalary()){
return (int) -(o1.getSalary()-o2.getSalary());
}else if(o1.getAge()!=o2.getAge()){
return (int) (o1.getAge()-o2.getAge());
}else if(o1.getName()!=o2.getName()){
return o1.getName().compareTo(o2.getName());}
else{
if(o1.getBook().price!=o2.getBook().price){
return (int) (o1.getBook().price-o2.getBook().price);
}else{
return o1.getBook().bookname.compareTo(o2.getBook().bookname);
} }
}
}
Test类
import java.util.Set;
import java.util.TreeSet;
public class Test { public static void main(String[] args) {
SalaryCom s =new SalaryCom();
Set<Person> allset = new TreeSet<Person>(s); allset.add(new Person(22,"hjw",20000,"论语",50.0));
allset.add(new Person(22,"fyy",7000,"大学",40.0));
allset.add(new Person(22,"hjl",6000,"孟子",30.0));
allset.add(new Person(22,"hlq",10000,"中庸",20.0));
allset.add(new Person(24,"hsx",20000,"诗经", 40.0));
allset.add(new Person(22,"cl",20000,"离骚",10.0));
allset.add(new Person(22,"zsk",20000,"墨子",25.0));
allset.add(new Person(22,"hj",20000,"论语",50.0));
allset.add(new Person(22,"hjw",20000,"论语",22.0));
System.out.println(allset);
} }
使用匿名内部类自定义比较器Comparator
Book类
public class Book {
public String bookname;
public Double price;
public Book(){}
public Book(String bookname, double price) {
this.bookname = bookname;
this.price = price;
}
public String getBookname() {
return bookname;
}
public void setBookname(String bookname) {
this.bookname = bookname;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
@Override
public String toString() {
return "Book [bookname=" + bookname + ", price=" + price + "]";
}
}
Person类
public class Person {
private Integer age;
private String name;
private double salary;
private Book book;
public Person(Integer age, String name, double salary,String bookname, double price) { this.age = age;
this.name = name;
this.salary = salary;
this.book=new Book(bookname,price); }
public Integer getAge() {return age;}
public void setAge(Integer age) {
this.age = age;
}
public Book getBook() {
return book;
}
public void setBook(Book book) {
this.book = book;
}
public void setSalary(double salary) {
this.salary = salary;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getSalary() {
return salary;
} @Override
public String toString() {
return "Person [age=" + age + ", name=" + name + ", salary=" + salary + ", book=" + book + "]";
} }
Test测试类
import java.util.Comparator;
import java.util.Set;
import java.util.TreeSet; import com.qianfeng.homework02.Person; public class Test { public static void main(String[] args) {
Set<Person> allset = new TreeSet<Person>(new Comparator<Person>() { @Override
public int compare(Person o1, Person o2) {
if(o1.getSalary()!=o2.getSalary()){
return (int) -(o1.getSalary()-o2.getSalary());
}else if(o1.getAge()!=o2.getAge()){
return (int) (o1.getAge()-o2.getAge());
}else if(o1.getName()!=o2.getName()){
return o1.getName().compareTo(o2.getName());}
else{
if(o1.getBook().price!=o2.getBook().price){
return (int) (o1.getBook().price-o2.getBook().price);
}else{
return o1.getBook().bookname.compareTo(o2.getBook().bookname);
} }
}
}); allset.add(new Person(22,"hjw",20000,"论语",50.0));
allset.add(new Person(22,"fyy",7000,"大学",40.0));
allset.add(new Person(22,"hjl",6000,"孟子",30.0));
allset.add(new Person(22,"hlq",10000,"中庸",20.0));
allset.add(new Person(24,"hsx",20000,"诗经", 40.0));
allset.add(new Person(22,"cl",20000,"离骚",10.0));
allset.add(new Person(22,"zsk",20000,"墨子",25.0));
allset.add(new Person(22,"hj",20000,"论语",50.0));
allset.add(new Person(22,"hjw",20000,"论语",22.0));
System.out.println(allset.size());
System.out.println(allset); } }
注意：String 字符串类的Comparator已经实现了compareTo方法，可以直接进行调用比较！
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