stream流做的那些事

江湖小Q2024-01-05 19:59

假如一个学生类的list集合，返回50条数据；我只需要该集合中的学生姓名name字段，其他的字段都不想要，那么可以

java 复制代码

String gender="男";
List<Student> students = studentMapper.selectListByQuery(QueryWrapper.create()
.where(STUDENT.GENDER.eq(gender)));
List<String> nameList = students.stream().map(Student::getName).collect(Collectors.toList());
//nameList存的全是name字段的值

通过stram流把Student集合转换成StudentAo集合，案例

java 复制代码

 public R<Page<StudentAo>> sysGetPage(@RequestBody StudentVo vo) {
        Page<Student> page = studentService.page(vo.getPage(), vo.giveQuerywrapper());
        Page<StudentAo> pageAo =new Page<>();
        List<Student> records = page.getRecords();
        List<StudentAo> collect = records.stream().map(student -> {
            StudentAo ao = new StudentAo();
            BeanUtils.copyProperties(student, ao);
            return ao;
        }).collect(Collectors.toList());
        pageAo.setRecords(collect);
        pageAo.setPageSize(page.getPageSize());
        pageAo.setPageNumber(page.getPageNumber());
        pageAo.setTotalPage(page.getTotalPage());
        pageAo.setTotalRow(page.getTotalRow());
        return R.ok("成功",pageAo);
    }