import java.util.*; import java.util.stream.Collectors; public class Main { public static void main(String[] args) { List<Map<String, List<String>>> list = new ArrayList<>(); // 创建测试数据 Map<String, List<String>> map1 = new HashMap<>(); map1.put...
Map<String,List<String>>map=list.stream().collect(Collectors.toMap(Person::getId,p->{List<String>getNameList=newArrayList<>();getNameList.add(p.getName());returngetNameList;},(List<String>value1,List<String>value2)->{value1.addAll(value2);returnvalue1;}));System.out.println(map); 输...
publicstaticvoidmain(String[] args) {//自定义function函数,自定义消费函数Stream.of("1").map(e->e+")").forEach(e->System.out.println(e));//forEach 引用消费函数Stream.of("1").map(e->e+")").forEach(System.out::println); Stream.of("1").mapToInt(e->Integer.valueOf(e)).forE...
publicstaticvoidmain(String[]args){List<Student>stu=newArrayList<>();Students1=newStudent();s1.setId(1);s1.setName("zs");Students2=newStudent();s2.setId(1);s2.setName("ls");Students3=newStudent();s3.setId(3);s3.setName("ww");stu.add(s1);stu.add(s2);stu.add(s3);stu.str...
那么就删掉filter过滤器 List<String> stringList = list.stream().filter(posDataDetailVo1 -> "李四".equals(posDataDetailVo1.getAccountNo())).map(PosDataDetailVo::getAccountNo).collect(Collectors.toList()); //也可以用下面这种方式,一样的 //List<String> stringList = list.stream().filter(...
Map<String,String>userMap=entityList.stream().collect(Collectors.toMap(UserEntity::getUserId,UserEntity::getUserName)); 1. 注:当userId出现重复的情况,会报Duplicate key的错误。 方式二:key是对象中的某个属性值,value是对象本身。 key为userId、value为UserEntity对象 ...
4、Map转换为Map Map<String, Object> codeMap = ipsService.getSelect(codes); Map<String, Object> envRiskLevelMap = ((List<BasCode>) codeMap.get(BimsConsts.CODE_ENVRISKLEVEL)).stream().collect(Collectors.toMap(BasCode::getCode, BasCode::getName, (k1, k2) -> k1)); ...
java Stream转化未带List的map stream list转string,JavaStreamAPI是Java8引入的函数式编程API使用stream前:List使用stream后:ListStream的优势:提升性能:stream会记录下过程操作、并对这些操作进行叠加,最后在一个迭代循环中执行所有叠加的操作,减少迭代次数代码简
public static void main(String[] args) { List<Person> people = Arrays.asList( new Person("Alice", 25), new Person("Bob", 30), new Person("Charlie", 35) ); Map<String, Integer> ageByName = people.stream() .collect(Collectors.toMap(Person::getName, Person::getAge)); ...