Comparable接口对list的多条件排序

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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 People implements Comparable<Field> {    private String name;    private int age;    public People() {    }    public People(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;    /**    @Override    public int compareTo(Object o) {        if(!(o instanceof FormControl))            return 0;        FormControl lo = (FormControl)o;        // 先按group排序        if(lo.getGroup().compareTo(this.group)<0){            return 1;        }        if(lo.getGroup().compareTo(this.group)>0){            return -1;        }        if(lo.getSerialNumber() > this.serialNumber)            return -1;        else if( lo.getSerialNumber() < this.serialNumber)            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) {        People f1 = new People("t", 11);        People f2 = new People("j", 11);        People f3 = new People("t", 11);        People f4 = new People("j", 44);        List<People> list = new ArrayList<People>();        list.add(f1);        list.add(f3);        list.add(f4);        list.add(f2);        Collections.sort(list);        for (People o : list) {            System.out.println(o.getAge() + "<-->" + o.getName());        }    }}

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