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  • JDK1.8对List指定字段进行排序

    import java.util.ArrayList;
    import java.util.Collections;
    import java.util.Comparator;
    import java.util.List;

    import com.wubei.demo.bean.Order;


    /**
    * List根据指定字段进行排序
    *
    */
    public class ListStreamTest {

    public static void main(String[] args) {


    String orderId1 = "2321837281372913";
    String userId1 = "20180701001";
    String orderId2 = "2321837281372914";
    String userId2 = "20180701002";
    String orderId3 = "2321837281372912";
    String userId3 = "20180701003";
    String orderId4 = "2321837281372918";
    String userId4 = "20180701005";
    String orderId5 = "2321837281372918";
    String userId5 = "20180701004";

    Order order = new Order();
    order.setUserId(userId1);
    order.setOrderId(orderId1);
    Order order1 = new Order();
    order1.setOrderId(orderId2);
    order1.setUserId(userId2);

    Order order2 = new Order();
    order2.setOrderId(orderId3);
    order2.setUserId(userId3);
    Order order3 = new Order();
    order3.setOrderId(orderId4);
    order3.setUserId(userId4);
    Order order4 = new Order();
    order4.setOrderId(orderId5);
    order4.setUserId(userId5);
    List<Order> orderList = new ArrayList<Order>();
    orderList.add(order);
    orderList.add(order1);
    orderList.add(order2);
    orderList.add(order3);
    orderList.add(order4);

    //1.jdk8 lambda排序,带参数类型
    orderList.sort(( Order ord1, Order ord2) -> ord2.getOrderId().compareTo(ord1.getOrderId()));

    //2.jdk8 lambda排序,不带参数类型
    orderList.sort(( ord1, ord2) -> ord2.getOrderId().compareTo(ord1.getOrderId()));

    //3.jdk8 升序排序,Comparator提供的静态方法
    Collections.sort(orderList, Comparator.comparing(Order::getOrderId));

    //4.jdk8 降序排序,Comparator提供的静态方法
    Collections.sort(orderList, Comparator.comparing(Order::getOrderId).reversed());

    //5.jdk8 组合排序,Comparator提供的静态方法,先按orderId排序,orderId相同的按userId排序
    Collections.sort(orderList, Comparator.comparing(Order::getOrderId).reversed().thenComparing(Order::getUserId));

    orderList.stream().forEach(str -> System.out.println(str.getOrderId()+"/" + str.getUserId()));

    }
    }

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  • 原文地址:https://www.cnblogs.com/WAbby/p/9249833.html
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