java基础学习之可比性的实现

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两种方法：一种是在类内部实现；一种是在类外部定义一个类的可比器
    package in;import java.util.ArrayList;import java.util.Arrays;import java.util.Comparator;/** * Created by S_eve on 2017/6/16. * 关于排序的两个接口 */public class TestJiakou {    public static void main(String[] args) {        //第一种方法        Student[] students1 = new Student[7];        students1[0] = new Student(7, "hah");        students1[1] = new Student(3, "hah");        students1[2] = new Student(5, "hah");        students1[3] = new Student(1, "hah");        students1[4] = new Student(4, "hah");        students1[5] = new Student(2, "hah");        students1[6] = new Student(6, "hah");        Arrays.sort(students1);        for(int i = 0; i < 7; i++){            System.out.println(students1[i].toString());        }        System.out.println("+++++++++++++++++++++++++++++++++++++");        //第二种        Student1[] students2 = new Student1[7];        students2[0] = new Student1(7, "hah");        students2[1] = new Student1(3, "hah");        students2[2] = new Student1(5, "hah");        students2[3] = new Student1(1, "hah");        students2[4] = new Student1(4, "hah");        students2[5] = new Student1(2, "hah");        students2[6] = new Student1(6, "hah");        Arrays.sort(students2, new StudentComparator());        for(int i = 0; i < 7; i++){            System.out.println(students2[i].toString());        }    }}//第一种方法，在类内部实现Comparableclass Student implements Comparable{    private int id;    private String name;    public Student(int id, String name) {        this.id = id;        this.name = name;    }    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    @Override    public boolean equals(Object o) {        if(this == o)            return true;        if(!(o instanceof Student))            return false;        Student other = (Student)o;        if(this.id == other.id && this.name.equals(other.name))            return true;        return false;    }    @Override    public int hashCode() {        int result = id;        result = 31 * result + (name != null ? name.hashCode() : 0);        return result;    }    @Override    public String toString() {        return "Student{" +                "id=" + id +                ", name='" + name + '\'' +                '}';    }    @Override    public int compareTo(Object o) {        Student other = (Student)o;        if(this.id < other.id){            return -1;        }else if(this.id > other.id) {            return 1;        }        return 0;    }}class Student1{    private int id;    private String name;    public Student1(int id, String name) {        this.id = id;        this.name = name;    }    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    @Override    public boolean equals(Object o) {        if(this == o)            return true;        if(!(o instanceof Student1))            return false;        Student1 other = (Student1)o;        if(this.id == other.id && this.name.equals(other.name))            return true;        return false;    }    @Override    public int hashCode() {        int result = id;        result = 31 * result + (name != null ? name.hashCode() : 0);        return result;    }    @Override    public String toString() {        return "Student1{" +                "id=" + id +                ", name='" + name + '\'' +                '}';    }}//第二种定义一个类比较器class StudentComparator implements Comparator{    @Override    public int compare(Object o1, Object o2) {        Student1 other1 = (Student1)o1;        Student1 other2 = (Student1)o2;        if(other1.getId() < other2.getId()){            return -1;        }else if(other1.getId() > other2.getId()){            return 1;        }        return 0;    }}
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