Question

我有一个基本的SpringBoot应用程序。使用Spring Initializer，JPA，嵌入式Tomcat，Thymeleaf模板引擎和包作为可执行的JAR文件我有这段代码来比较POJO，但是隔离似乎不起作用，因为lastDeviceEvent和firstDeviceEvent是具有相同ID的同一对象

DeviceEvent lastDeviceEvent = null;
        DeviceEvent firstDeviceEvent = null;

        try {       

            lastDeviceEvent = deviceEvents
                            .stream()
                            .filter (o -> o.getId().equals(deviceId))
                            .sorted(comparing((DeviceEvent de) -> de.getId()).reversed())
                            .findFirst().get();



            firstDeviceEvent = deviceEvents
                    .stream()
                    .filter (o -> o.getId().equals(deviceId)) 
                    .sorted(comparing((DeviceEvent de) -> de.getId()))
                    .findFirst().get();


            LOG.info("lastDeviceEvent --> " + lastDeviceEvent.getId());
            LOG.info("firstDeviceEvent -> " + firstDeviceEvent.getId());


        } catch (NoSuchElementException nse) {

            throw new AccessDeniedException("403 Forbidden");

        }

Answer 1

比较器似乎是正确的。问题似乎出现在您的过滤条款中，您将事件ID 与设备ID 进行比较

lastDeviceEvent = deviceEvents
                .stream()
                .filter (o -> o.getDeviceId().equals(deviceId)) // Original code used getId()
                .sorted(comparing((DeviceEvent de) -> de.getId()).reversed())
                .findFirst()
                .get();

Java 8比较器无法正常工作

1 个答案: