如何在 Spring 引導中對 List<> 中的月份進行排序 - 使用 Java 8

Question

我有月份列表，我在 POJO class 中設置，在設置時，訂單沒有排序。 我想整理一下。 樣本數據看起來像 -

我的 POJO Class -

public class SamplePojo {
   private static final long serialVersionUID = 1L;
   private String type;
   private String name;
   private Integer January;
   private Integer February;
   private Integer March;
   private Integer April;
   private Integer May;
   private Integer June;
}

ServiceImpl -

List<SamplePojo> sp = new ArrayList<SamplePojo>();
SamplePojo tp1 = new SamplePojo ();
        
        tp1.type("type");
        tp1.name("name");
        tp1.setJanuary(12);
        tp1.setFebruary(2);
        tp1.setMarch(33);
        tp1.setApril(0);
        tp1.setMay(0);
        tp1.setJune(0);
        tp1.setTotal(122);
        sp.add(tp1);

未排序的數據 -

[
    {
        "type": "LLB",
        "name": "Working",
        "total": 0,
        "march": 33,
        "april": 0,
        "may": 0,
        "june": 0,
        "february": 2,
        "january": 12
    },
    {
        "type": "Engineer",
        "name": "Not Working",
        "total": 0,
        "march": 33,
        "april": 0,
        "may": 0,
        "june": 0,
        "february": 2,
        "january": 12
    }
]

想要排序 -

[
    {
        "type": "LLB",
        "name": "Working",
        "january": 11,
        "february": 2,
        "march": 3,
        "april": 3,
        "may": 0,
        "june": 0,
        "total": 0
    },
    {
        "type": "Engineer",
        "name": "Not Working",
        "january": 12,
        "february": 2,
        "march": 33,
        "april": 0,
        "may": 0,
        "june": 0,
        "total": 0
    }
]

如何使用 Spring 啟動來做到這一點。 我是這個 Spring 啟動的新手，也是這個 stackoverflow 的新手。 你能幫幫我嗎？

Answer 1

如果要對 JSON 有效載荷進行排序，可以使用@JsonPropertyOrder注解

@JsonPropertyOrder({
  "type",
  "name",
  "January",
  "February",
  "March"
})
public class SamplePojo {
  private static final long serialVersionUID = 1 L;
  private String type;
  private String name;
  private Integer January;
  private Integer February;
  private Integer March;
  private Integer April;
  private Integer May;
  private Integer June;
}

Answer 2

最好的方法是使用Spring Data Repository 查詢關鍵字從存儲庫中排序，通過以下代碼查找所有SampleEntity 。

@Repository
public interface SampleEntityRepository extends JpaRepository<SampleEntity, Long> {
    List<SampleEntity> findAllByOrderByJanuaryAsc();
}

但是，如果您想在最后一層排序以顯示List of SamplePojo您可以使用stream並按某些標准sorted 。

List<SamplePojo> lastList = sampleService.findAll();
lastList
    .stream()
    .sorted((sPojo1, sPojo2) -> sPojo1.getJanuary().compareTo(sPojo2.getJanuary()));