class Student{
private String id;
private List<Subject> subjectList;
}
class Subject{
private String subId;
private String subName;
pricate Integer soure;
}
假设有一个学生类,如上所示
将id作为key 将subject作为value;现在将List<Student> 转换成Map<String, Subject>
List<Student> studentList = getList();//获取Student类型的列表
studentList.stream().filter(data-> !Collections.isEmpty(data.getSubjectList)).collect(Collectors.toMap(Student::getId, data->data.getSubjectList.get(0)));
将id作为key 将List<Subject>作为value;现将List<Student> 转换成Map<String, List<Subject>>
List<Student> studentList = getList();//获取Student类型的列表
studentList.stream().collect(Collectors.toMap(Student::getId, data->data.getSubjectList));
给subject类对象赋值,其中成绩默认都是0分,科目名称都是数学
List<String> strList = getList();//获取String类型的列表
List<Subject> subjectList = strList.stream().map(id, "数学",0).collect(Collectors.toList());