使用Lambda表达式和Comparator进行自定义排序

package com.lambda;

/**
 * @Author zwp Created on 2018/8/16.
 */
public class AA {
    private Integer a ;
    private int b ;

    public Integer getA() {
        return a;
    }

    public void setA(Integer a) {
        this.a = a;
    }

    public int getB() {
        return b;
    }

    public void setB(int b) {
        this.b = b;
    }

    @Override
    public String toString() {
        return "AA{" +
                "a=" + a +
                ", b=" + b +
                };
    }
}

package com.lambda;

import org.junit.Test;

import java.util.*;


/**
 * @Author zwp Created on 2018/8/16.
 */
public class LambdaTest
{

   @Test
   public void test(){
      List<AA> a =new  ArrayList<AA>();
      AA aa1 = new AA();
      aa1.setA(1);
      AA aa2 = new AA();
      aa2.setA(3);
      AA aa3 = new AA();
      aa3.setA(2);
      a.add(aa1);
      a.add(aa2);
      a.add(aa3);
      System.out.println(a);
      a.sort((x,y)->{
         return x.getA() - y.getA();
      });
      System.out.println(a);
   }
}