JPA使用

    @Override
    public PageVo<PageUserVo> user(Integer page1, Integer size1, String name, Integer roleId) {
        Integer page = page1;
        Integer size = size1;
        page = VerificationUtils.checkPaging(page, size);
        Sort sort = Sort.by(Sort.Direction.DESC, "id");
        PageRequest pageRequest = PageRequest.of(page, size, sort);
        Specification<UserEntity> userEntitySpecification=(root, query, cb) -> {
            List<Predicate> predicates = new ArrayList<>();
            if (StringUtils.isNotBlank(name)) {
                Path<String> name1 = root.get("username");
                Path<String> realName = root.get("realName");
                Predicate one = cb.like(name1, "%" + name + "%");
                Predicate two = cb.like(realName, "%" + name + "%");
                //（one or two）
                Predicate or = cb.or(one, two);
                predicates.add(or);
            }
            if (roleId != null) {
                //连接表roles
                Join<Object, Object> roles = root.join("roles",JoinType.LEFT);
                Path<Integer> id = roles.get("id");
                Predicate one = cb.equal(id, roleId);
                predicates.add(one);
            }
            return cb.and(predicates.toArray(new Predicate[predicates.size()]));
        };
        Page<UserEntity> pageUsers = productDao.findAll(userEntitySpecification,pageRequest);
        List<PageUserVo> vos = pageUsers.getContent().stream().map(PageUserVo::mapping).collect(Collectors.toList());
        return new PageVo<>(++page, size, pageUsers.getTotalElements(), vos);
    }