普通java类(排序)实现Comparable接口重写CompareTo方法

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普通的类要实现排序，必须实现Comparable接口，并重写CompareTo()方法。

package test;public class Field implements Comparable<Field> {    private String name;    private int age;    public Field() {    }    public Field(String name, int age) {        this.name = name;        this.age = age;    }    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;    }    @Override    public int compareTo(Field o) {        // 先按age排序        if (this.age > o.getAge()) {            return (this.age - o.getAge());        }        if (this.age < o.getAge()) {            return (this.age - o.getAge());        }        // 按name排序        if (this.name.compareTo(o.getName()) > 0) {            return 1;        }        if (this.name.compareTo(o.getName()) < 0) {            return -1;        }        return 0;    }}

测试类按照某属性进行排序输出：

package test;import java.util.ArrayList;import java.util.Collections;import java.util.List;public class Test2 {    public static void main(String[] args) {        Field f1 = new Field("tony", 11);        Field f2 = new Field("jack", 11);        Field f3 = new Field("tom", 11);        Field f4 = new Field("jason", 44);        List<Field> list = new ArrayList<Field>();        list.add(f1);        list.add(f3);        list.add(f4);        list.add(f2);        Collections.sort(list);        for (Field o : list) {            System.out.println(o.getAge() + "-->" + o.getName());        }    }}

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