private static <T> Predicate<T> distinctByKey(Function<? super T, ?> keyExtractor) { Set<Object> seen = ConcurrentHashMap.newKeySet(); return t -> seen.add(keyExtractor.apply(t)); } 复制代码 使用如下: @Test public void distinctByProperty2() throws JsonProcessingException { // 这里第二...
private static Predicate distinctByKey(Function super T, ?>keyExtractor) { Set seen =ConcurrentHashMap.newKeySet();return t ->seen.add(keyExtractor.apply(t)); } 1. 2. 3. 复制代码 使用如下: @Testpublic void distinctByProperty2() throwsJsonProcessingException {//这里第二种方法我们通过过滤来...
2. Finding Distinct by Multiple Fields ‘using Custom Key Class’ Another possible approach is to havea custom class that represents the distinct keyfor the POJO class. For the previous example, we can create a classCustomKeycontaining first and last name values. The distinct elements from a l...
list.stream().filter(distinctByKey(b -> b.getName())); distinctByKey()方法返回一个使用ConcurrentHashMap来维护先前所见状态的Predicate实例,如下是一个完整的使用对象属性来进行去重的示例。 DistinctByProperty.java package com.concretepage; import java.util.ArrayList; import java.util.List; import java...
public void distinctByProperty() throws JsonProcessingException { // 这里第二种方法我们通过过滤来实现根据对象某个属性去重 ObjectMapper objectMapper = new ObjectMapper(); List<Student> studentList = getStudentList(); System.out.print("去重前 :"); ...
UsingCollectors.toMapin Java 8 streams is crucial for achieving distinct by property efficiently. It allows developers to create aMapwhere the property acts as the key, ensuring uniqueness. The method provides a clear and concise way to handle potential duplicates, offering control over which values...
publicvoiddistinctByProperty1()throwsJsonProcessingException { // 这里第一种方法我们通过新创建一个只有不同元素列表来实现根据对象某个属性去重 ObjectMapper objectMapper =new ObjectMapper(); List<Student> studentList = getStudentList(); out.print("去重前 :"); ...
distinct()使用hashCode()和equals()方法来获取不同的元素。因此,我们的类必须实现hashCode()和equals()方法。 如果distinct()正在处理有序流,那么对于重复元素,将保留以遭遇顺序首先出现的元素,并且以这种方式选择不同元素是稳定的。 在无序流的情况下,不同元素的选择不一定是稳定的,是可以改变的。distinct()执行...
然后可以在使用的时候 代码语言:javascript 代码运行次数:0 运行 AI代码解释 usersList.stream().filter(distinctByKey(User::getType)) 当然,如果 list 是并行的,那么distinct 保留其中某个元素,而不是第一个。 翻译自 https://stackoverflow.com/questions/23699371/java-8-distinct-by-property ...
简介:【Java异常】使用通用Mapper ,报There is no getter for property named ‘distinct‘ in ‘class 错 一、报错信息 Caused by: org.apache.ibatis.reflection.ReflectionException: There is no getter for property named 'distinct' in 'class com.uiotsoft.subsite.mybatis.model.TCmsSite' ...