先初始化一个 School 的集合,然后将该集合转成一个 Map,key 为 id, value 为 name。 注:学校的 id 设置为重复的。 上代码: publicstaticvoidmain(String[]args){List<School>schoolList=Lists.newArrayList(newSchool("1","a"),newSchool("2","b"),newSchool("1","c"));Map<String,School>schoolMa...
一、问题由来 最近生成环境刚发布了一个版本,本人负责优化的一个功能在进行测试时,报错了一个异常,duplicate key;去百度里面看了一下, 意思很明确就是建重复,而且错误是在Java代码中抛出来的。 二、问题分析 自己立马去查看Java代码,发现这样写是没有问题的,问题出在查询出来的结果进行转换时,键有重复的,可是有...
,Map<K,U>>toMap(Function<?superT, ?extendsK> keyMapper,Function<?superT, ?extendsU> valueMapper)publicstatic<T, K, U>Collector<T, ?,Map<K,U>>toMap(Function<?superT, ?extendsK> keyMapper,Function<?superT, ?extendsU> valueMapper,BinaryOperator<U> mergeFunction)publicstatic<T, K, U, ...
Map<String, String> map = list.stream().collect(Collectors.toMap(Student :: getClassName, Student :: getStudentName, (key1 , key2)-> key2 )); 1. 2. 2、重复时将之前的value 和现在的value拼接或相加起来; Map<String, String> map = list.stream().collect(Collectors.toMap(Student :: get...
java8 对象转Map时重复 key Duplicate key xxxx 我们在利⽤java8 Lambda 表达式将集合中对象的属性转成Map时就会出现 Duplicate key xxxx , 说⽩了也就是key 重复了！案例如下 @Getter @Setter @AllArgsConstructor public class Student{ private String className;private String studentName;public static void ...
Map存储两个key:Duplicate key 6 简介:Map存储两个key:Duplicate key 6 map中的key是唯一的,如果map存储出现重复的key就会报错,所以key一般要选择唯一索引的字段 解决方案 Map<String, Integer> sumTimeMap =workTimeVoList.stream().collect(Collectors.toMap(WorkTimeVo::getUserAccount, WorkTimeVo::getSumUse...
我们在利用java8 Lambda 表达式将集合中对象的属性转成Map时就会出现 Duplicate key xxxx , 说白了也就是key 重复了! 案例如下 @Getter @Setter @AllArgsConstructor public class Student{ private String className; private String studentName; public static void main(String[] args) { ...
duplicaterecordid_workqueueitem Unique identifier of the potential duplicate record. _duplicateruleid_value duplicateruleid Unique identifier of the duplicate rule against which this duplicate was found.Single-valued navigation propertiesSingle-valued navigation properties represent lookup fields where a single...
duplicaterecordid_workqueueitem Unique identifier of the potential duplicate record. _duplicateruleid_value duplicateruleid Unique identifier of the duplicate rule against which this duplicate was found.Single-valued navigation propertiesSingle-valued navigation properties represent lookup fields where a single...
@TestpublicvoidduplicateKeyDemo(){// 测试数据List<Commodity>list=this.getCommodityList();// 去重Map<String,Commodity>mapSuccess=list.stream().collect(Collectors.toMap(Commodity::getCode,Function.identity(),(commodity1,commodity2)->commodity1));log.info("mapSuccess:{}",mapSuccess);// 异常Map<...