Collections.sort排序方法的最简化写法
Collections.sort排序方法的最简化写法
假定按照Number对象的Id字段进行排序
正序排序
Collections.sort(resultList, Comparator.comparing(Number::getId));
逆序排序
Collections.sort(resultList, Comparator
.comparing(Number::getId, Comparator.reverseOrder()));
初始化map集合长度最优值
- 假设我们期望集合中存放的元素的数量是num,那么需要将集合长度设置为(num/0.75 + 1)
- 或者使用guava包的Maps.newHashMapWithExpectedSize()方法来初始化map
- 优势:减少集合的扩容次数,属于是使用内存换性能.
spring编程式事务实现
参考: https://blog.csdn.net/qq_33404395/article/details/83377382
Spring Boot之全局异常处理：404异常为何捕获不到？
spring.mvc.throw-exception-if-no-handler-found=true
spring.resources.add-mappings=false
参考:https://blog.csdn.net/w1014074794/article/details/106038996
kafka操作命令合集
LocalDate获取某月第一天第一秒和最后一天最后一秒
/**
* 获取某月份的第一天
*
* @param amount 传0获取当月第一天，传-1获取上个月第一天
* @return
*/
private LocalDateTime getFirstDayOfMonth(Integer amount) {
LocalDate now = LocalDate.now();
LocalDate date = now.plusMonths(amount);
LocalDate firstDay = date.with(TemporalAdjusters.firstDayOfMonth());
return LocalDateTime.of(firstDay, LocalTime.MIN);
}
/**
* 获取某月最后一天
*
* @param amount 传0获取当月最后一天，传-1获取上个月最后一天
* @return
*/
private LocalDateTime getLastDayOfMonth(Integer amount) {
LocalDate now = LocalDate.now();
LocalDate date = now.plusMonths(amount);
LocalDate lastDay = date.with(TemporalAdjusters.lastDayOfMonth());
return LocalDateTime.of(lastDay, LocalTime.MAX);
}
接口相应结果添加统一字段
@Component
@ControllerAdvice
public class CustomResponseBodyAdvice implements ResponseBodyAdvice {
@Override
public boolean supports(MethodParameter returnType, Class> converterType) {
// 指定需要处理的控制器方法的返回类型
// 这里可以根据需求进行适当的判断，例如基于注解或返回类型等条件
return true;
}
@Override
public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType,
Class> selectedConverterType,
ServerHttpRequest request, ServerHttpResponse response) {
// 获取返回结果对象，并进行字段设置
if (body instanceof ApiResponse) {
ApiResponse responseObj = (ApiResponse) body;
HttpServletRequest httpRequest = ((ServletServerHttpRequest) request).getServletRequest();
// 从HttpServletRequest中获取请求的方法、URL和URI
String method = httpRequest.getMethod();
String url = httpRequest.getRequestURL().toString();
String uri = httpRequest.getRequestURI();
// 向返回结果对象中补充设置字段
responseObj.setAction(method);
responseObj.setPath(url);
responseObj.setUri(uri);
responseObj.setOrganization(url.split("/")[3]);
}
return body;
}
}
Original: https://www.cnblogs.com/MorningBell/p/16659416.html
Author: MorningBell
Title: Collections.sort排序方法的最简化写法
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