java 自定义类比较器

java 自定义类比较器

示例：

package com.myfile;import java.util.ArrayList;import java.util.Collections;import java.util.Comparator;import java.util.List;/** * Created by tengfei on 2017/10/27 */public class CompareTest {    /**     * 内部比较器：Comparable, 重写conpareTo方法     */    @SuppressWarnings("rawtypes")    class Student1 implements Comparable {        private String name;        private int age;        public Student1(int age, String name) {            this.age = age;            this.name = name;        }        @Override        public String toString() {            return "\tStudent1 age: " + age + ", name: " + name + "\r";        }        @Override        public int compareTo(Object o) {            Student1 tmp = (Student1) o;            int result = tmp.age < age ? 1 : (tmp.age == age ? 0 : -1);            return result = result == 0 ? (tmp.name.trim().compareTo(name.trim()) < 0 ? 1 : -1) : result;        }    }    // -------------------------------------------------------------------------------------    /**     * 外部比较器：Comparator, 定义comparator比较类     */    class Student2 {        private String name;        private int age;        public Student2(int age, String name) {            this.age = age;            this.name = name;        }        @Override        public String toString() {            return "\tStudent2 age: " + age + ", name: " + name + "\r";        }    }    @SuppressWarnings("rawtypes")    public static class Student2Comparator implements Comparator {        public int compare(Object o1, Object o2) {            Student2 t1 = (Student2) o1;            Student2 t2 = (Student2) o2;            int result = t1.age > t2.age ? 1 : (t1.age == t2.age ? 0 : -1);            return result = result == 0 ? (t1.name.trim().compareTo(t2.name.trim()) > 0 ? 1 : -1) : result;        }        @SuppressWarnings("unchecked")        public static void main(String[] args) {            CompareTest co = new CompareTest();            List<Student1> list1 = new ArrayList<Student1>();            list1.add(co.new Student1(1, "aa"));            list1.add(co.new Student1(2, "abb"));            list1.add(co.new Student1(2, "acc"));            list1.add(co.new Student1(3, "dd"));            Collections.sort(list1); // 内部比较器:要排序的对象实现Comparable接口,可以对自身进行比较            System.out.println(list1);            List<Student2> list2 = new ArrayList<Student2>();            list2.add(co.new Student2(1, "aa"));            list2.add(co.new Student2(2, "abb"));            list2.add(co.new Student2(2, "acc"));            list2.add(co.new Student2(3, "dd"));            Collections.sort(list2, new Student2Comparator()); // 外部比较器:通过实现Comparator接口            System.out.println(list2);        }    }}