标签:out 组成 代码 math 字符串排序 字母 ascii .so import
1、排序对象全是字母组成,可以根据ASCII编码表排序
package com.abcd;
public class Person{
private String name;
private int age;
private int salary;
public Person() {
}
public Person(String name, int age, int salary) {
this.name = name;
this.age = age;
this.salary = salary;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public int getSalary() {
return salary;
}
public void setSalary(int salary) {
this.salary = salary;
}
@Override
public String toString() {
return "Person{" +
"name=‘" + name + ‘\‘‘ +
", age=" + age +
", salary=" + salary +
‘}‘;
}
}
2、排序测试代码
package com.abcd;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
public class PersonTest {
public static void main(String[] args){
List<Person> people = new ArrayList<>();
people.add(new Person("ZZZ",20,100));
people.add(new Person("aaa",48,109));
people.add(new Person("aa",30,109));
System.out.println(people);
Collections.sort(people, new Comparator<Person>() {
@Override
public int compare(Person o1, Person o2) {
return o1.getName().toLowerCase().compareTo(o2.getName().toLowerCase());
}
});
System.out.println(people);
}
}
int comparaTo( )方法底层源码:
public int compareTo(String anotherString) {
int len1 = value.length;
int len2 = anotherString.value.length;
int lim = Math.min(len1, len2);
char v1[] = value;
char v2[] = anotherString.value;
//首先的比较规则,比较首字母,依次第二位字母,第三位字母等逐个比较
int k = 0;
while (k < lim) {
char c1 = v1[k];
char c2 = v2[k];
if (c1 != c2) {
return c1 - c2;
}
k++;
}
//然后字母比较完了后,比较字符串的长度
return len1 - len2;
}
3、运行结果
[Person{name=‘ZZZ‘, age=20, salary=100}, Person{name=‘aaa‘, age=48, salary=109}, Person{name=‘aa‘, age=30, salary=109}]
[Person{name=‘aa‘, age=30, salary=109}, Person{name=‘aaa‘, age=48, salary=109}, Person{name=‘ZZZ‘, age=20, salary=100}]
2、排序目标全是中文,实现首字母排序
package com.abcd;
import java.text.Collator;
import java.util.*;
public class PersonTest {
public static void main(String[] args){
List<Person> people = new ArrayList<>();
people.add(new Person("博泰",20,100));
people.add(new Person("阿明",48,109));
people.add(new Person("啊",30,109));
System.out.println(people);
Collections.sort(people, new Comparator<Person>() {
@Override
public int compare(Person o1, Person o2) {
Comparator cmp = (Collator.getInstance(Locale.CHINA));
return cmp.compare(o1.getName(), o2.getName());
}
});
System.out.println(people);
}
}
运行结果:
[Person{name=‘博泰‘, age=20, salary=100}, Person{name=‘阿明‘, age=48, salary=109}, Person{name=‘啊‘, age=30, salary=109}] [Person{name=‘啊‘, age=30, salary=109}, Person{name=‘阿明‘, age=48, salary=109}, Person{name=‘博泰‘, age=20, salary=100}]
十五、Collections.sort(<T>, new Comparator<T>() {})针对字符串排序
标签:out 组成 代码 math 字符串排序 字母 ascii .so import
原文地址:https://www.cnblogs.com/mason117/p/10646619.html