java接口返回参数按照请求参数进行排序方式

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java接口返回参数按照请求参数进行排序

在项目实际开发中可能遇到过这种问题，接口请求参数顺序是[a,b,c]，结果返回的数据是[bObject，cObject，aObject]，导致这种原因可能是底层采用了设计模式，或者是表拼接查询，本文主要就是为了实现这种功能，采用流的方法

代码实现

import lombok.Data;
import java.io.Serializable;
/**
* @description 模拟接口结果类
* @author: WilsonMeng
* @create: 2021-01-26 14:26
**/
@Data
public class SkuInfo implements Serializable {
  private static final long serialVersionUID = -6242151519713186291L;
  /**
   * spuId
   */
  private String spuId;
  /**
   * skuId
   */
  private String skuId;
  /**
   * 商品名称
   */
  private String productName;
  /**
   * 商品图片
   */
  private String picture;
  /**
   * 商品链接
   */
  private String link;
}

排序

import com.alibaba.fastjson.JSON;
import com.google.common.collect.Lists;
import com.wanli.databoard.dto.SkuInfo;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.Objects;
import java.util.stream.Collectors;
/**
* @description
* @author: WilsonMeng
* @create: 2021-01-26 14:28
**/
public class SkuSortTest {
  public static void main(String[] args) {
      List<String> skuIdList = Arrays.asList("sku1", "sku2", "sku3", "sku4");
      //用于模拟接口入参
      System.out.println("skuid列表：" + JSON.toJSONString(skuIdList));
      System.out.println();
      List<SkuInfo> skuInfoList = Lists.newArrayList();
      SkuInfo s1 = new SkuInfo();
      s1.setSpuId("spu1");
      s1.setSkuId("sku1");
      s1.setProductName("商品1");
      s1.setPicture("p1");
      s1.setLink("link1");
      skuInfoList.add(s1);
      SkuInfo s4 = new SkuInfo();
      s4.setSpuId("spu1");
      s4.setSkuId("sku4");
      s4.setProductName("商品2");
      s4.setPicture("p4");
      s4.setLink("link4");
      skuInfoList.add(s4);
      SkuInfo s3 = new SkuInfo();
      s3.setSpuId("spu2");
      s3.setSkuId("sku3");
      s3.setProductName("商品3");
      s3.setPicture("p3");
      s3.setLink("link3");
      skuInfoList.add(s3);
      SkuInfo s2 = new SkuInfo();
      s2.setSpuId("spu2");
      s2.setSkuId("sku2");
      s2.setProductName("商品2");
      s2.setPicture("p2");
      s2.setLink("link2");
      skuInfoList.add(s2);
      //用于模拟接口入参
      System.out.println("skuInfoList列表：" + JSON.toJSONString(skuInfoList));
      System.out.println();
      //按照请求参数进行排序
      List<SkuInfo> resultList = skuInfoList.stream().sorted(getSkuIdListComparator(skuIdList)).collect(Collectors.toList());
      System.out.println("排序完成后的结果：" + JSON.toJSONString(resultList));
  }
  private static Comparator<SkuInfo> getSkuIdListComparator(List<String> skuIds) {
      return (o1, o2) -> {
          int order1 = 0, order2 = 0;
          for (int i = 0; i < skuIds.size(); i++) {
              if (Objects.equals(o1.getSkuId(), skuIds.get(i))) {
                  order1 = i;
              }
              if (Objects.equals(o2.getSkuId(), skuIds.get(i))) {
                  order2 = i;
              }
          }
          return order1 - order2;
      };
  }
}

代码运行结果：

skuid列表：["sku1","sku2","sku3","sku4"]

skuInfoList列表：[{"link":"link1","picture":"p1","productName":"商品1","skuId":"sku1","spuId":"spu1"},{"link":"link4","picture":"p4","productName":"商品2","skuId":"sku4","spuId":"spu1"},{"link":"link3","picture":"p3","productName":"商品3","skuId":"sku3","spuId":"spu2"},{"link":"link2","picture":"p2","productName":"商品2","skuId":"sku2","spuId":"spu2"}]

排序完成后的结果：[{"link":"link1","picture":"p1","productName":"商品1","skuId":"sku1","spuId":"spu1"},{"link":"link2","picture":"p2","productName":"商品2","skuId":"sku2","spuId":"spu2"},{"link":"link3","picture":"p3","productName":"商品3","skuId":"sku3","spuId":"spu2"},{"link":"link4","picture":"p4","productName":"商品2","skuId":"sku4","spuId":"spu1"}]

java通过接口进行排序

描述

对学生排序，先按成绩由大到小排序，成绩相同按姓名字母排序，姓名相同再按学号由小到大排序。

package src7;
  import java.util.*;
  class Student implements Comparable<Student>  {
      private String name;
      private int id;
      private int grade;
  public Student(String name, int id, int grade) {
      this.name = name;
      this.id = id;
      this.grade = grade;
  }
  public int compareTo(Student o) {
          Student s = (Student) o;
          if (this.grade>s.grade) {
              return -1;//返回负数,当前成绩排前
          } else if (this.grade == s.grade) {
//                if (this.name.hashCode() < s.name.hashCode()) {
//                    return -1;          //使用hashCode()
              if (this.name.compareTo(s.name)<0) {
                  return -1;            //使用compareTo
//                } else if (this.name.hashCode() == s.name.hashCode()) {
              } else if (this.name.compareTo(s.name)==0) {
                  if (this.id < s.id) {
                      return -1;
                  } else if (this.id == s.id) {
                      return 0;//此处说明姓名学号成绩全部相同
                  } else {
                      return 1;
                  }
              } else {
                  return 1;// 返回正数，当前对象排后
              }
          } else {
              return 1;
          }
      }
  @Override
  public String toString() {
      return "姓名：" + this.name +",学号："+this.id+ ",成绩：" + this.grade + "\n";
  }
}
public class Test {
  public static void main(String[] args) {
      Scanner in = new Scanner(System.in);
      Student[] arr = new Student[3];
      for (int i = 0; i < arr.length; i++) {
          System.out.println("输入第" + (i + 1) + "个学生的姓名、学号和成绩：");
          String name = in.next();
          int id = in.nextInt();
          int grade = in.nextInt();
          arr[i] = new Student(name, id, grade);
      }
      System.out.println("排序前：");
      for(int i = 0; i < arr.length; i++){
          System.out.println(arr[i]);
      }
      System.out.println("排序后：");{
      List<Student>students=Arrays.asList(arr);
      Collections.sort(students);
      System.out.println(students);
      //也可以使用冒泡排序
      for(int i=0;i<arr.length;i++) {
          System.out.println(arr[i]);
      }
      }   
      }
  }

知识点

1.Comparable接口

包含的比较方法：

public interface Comparable< T >{
public int compareTo(T obj);
}

比较当前对象与外来对象，让当前对象排前就返回负值，反之返回正值，相等返回0

关于Comparable接口的简单举例：对人的姓和名进行排序

package src7;
import java.util.*;
class Person implements Comparable<Person>{
  private final String lastname,firstname;//lastname表示姓 firstname表示名
  public Person(String lastname,String firstname){
      this.lastname=lastname;
      this.firstname=firstname;
  }
  public String lastname(){
      return lastname;
  }
  public String firstname(){
      return firstname;
  }
  public boolean equals(Object obj){
      Person n=(Person)obj;
      return (n.lastname.equals(lastname)&&n.firstname.equals(firstname));
  }
  public int hashCode(){
      return lastname.hashCode()+firstname.hashCode();
  }
  public String toString(){
      return lastname+" "+firstname;
  }
  public  int compareTo(Person n){
      if(lastname.compareTo(n.lastname)<0)
          return -1;
     if(lastname.compareTo(n.lastname)>0)
         return 1;
     else {
         if(firstname.compareTo(n.firstname)<0)
             return -1;
         if(firstname.compareTo(n.firstname)>0)
             return 1;
         else return 0;
     }
  }
}
public class Test {
  public static void main(String[]args){
      Person personArr[]={
              new Person("Zhang","Liang"),
              new Person("Li","Si"),
              new Person("Wang","Ning"),
              new Person("Zhang","San"),
              new Person("Chen","Yi")
      };
      List<Person>persons=Arrays.asList(personArr);
      Collections.sort(persons);
      System.out.println(persons);
  }
}

运行结果：

java接口返回参数按照请求参数进行排序方式

2.Comparator接口

包含的比较方法：

public interface Comparator< T >{
public int compare(T obj1,T obj2);
}

比较对象obj1和obj2，让obj1位于obj2之前则返回负值

简单举例：对姓名排序

package src7;
import sun.awt.geom.AreaOp;
import java.util.*;
class Person{
  private String name;
  public Person(String name){
      this.name=name;
  }
  public String getName(){
      return name;
  }
  public String toString(){
      return name;
  }
}
public class Test{
  static final Comparator<Person> ODER_BY_NAME=new Comparator<Person>() {
      @Override
      public int compare(Person o1, Person o2) {
          return o1.getName().compareTo(o2.getName());
      }
  };
   public static void main(String[] args) {
       Person personArr[]={
              new Person("ZhangLiang"),
              new Person("LiSi"),
              new Person("WangNing"),
               new Person("ZhangSan"),
              new Person("ChenYi")
      };
       List<Person>persons=Arrays.asList(personArr);
      Collections.sort(persons,ODER_BY_NAME);
      System.out.println(persons);
       }
   }

运行结果：

java接口返回参数按照请求参数进行排序方式