public void exporttoexcel(CreditHrtExchstatementQueryDTo creditHrtExchstatementqueryDTo HttpServletResponse response){ log.info("华润通积分兑换明细报表导出开始，参数--》{}"，creditHrtExchstatementQueryDTO); File file =creditHrtExchStatementService.export(creditHrtExchstatementQueryDTo); String fileName = ""; try { fileName =URLEncoder.encode(file.getNameO), enc: “UTF-8").replaceall regec "\\+" replacement "%20") } catch (UnsupportedEncodingException e) { throw new BizException("文件导出错误")} try { SecureHttpUtils.exportExcel(response, file, fileName deleteFileAfterExport true); } catch (I0Exception e) { throw new BizException(“文件用出销误”:} log.info("华润通积分兑换朋细报表导出，结束“)。根据以上代码编写单元测试，需要使用mockito.lenient().when(xx).thenReturn，直接mock掉Serivice层的内容

根据您提供的代码，我可以给出一个单元测试的示例：

@RunWith(MockitoJUnitRunner.class)
public class CreditHrtExchStatementControllerTest {

    @InjectMocks
    private CreditHrtExchStatementController controller;

    @Mock
    private CreditHrtExchStatementService service;

    @Mock
    private HttpServletResponse response;

    @Test
    public void testExportToExcel() throws UnsupportedEncodingException, IOException {
        // mock service method
        File file = new File("test.xls");
        Mockito.lenient().when(service.export(Mockito.any(CreditHrtExchstatementQueryDTO.class))).thenReturn(file);

        // call controller method
        CreditHrtExchstatementQueryDTO dto = new CreditHrtExchstatementQueryDTO();
        controller.exporttoexcel(dto, response);

        // verify response
        Mockito.verify(response, Mockito.times(1)).setContentType("application/vnd.ms-excel");
        Mockito.verify(response, Mockito.times(1)).setHeader("Content-Disposition", "attachment;filename=\"" + URLEncoder.encode(file.getName(), "UTF-8").replaceAll("\\+", "%20") + "\"");
        Mockito.verify(response, Mockito.times(1)).setContentLength((int) file.length());
        Mockito.verify(response.getOutputStream(), Mockito.times(1)).write(Mockito.any(byte[].class));
        Mockito.verify(response.getOutputStream(), Mockito.times(1)).flush();
        Mockito.verify(response.getOutputStream(), Mockito.times(1)).close();

        // verify service method
        Mockito.verify(service, Mockito.times(1)).export(dto);

        // verify log
        // ...
    }
}

这个示例中，我们使用了 Mockito 框架来 mock 掉 Service 层的内容，然后测试 Controller 层的方法是否能够正确地将数据导出到 Excel 文件，并将文件写入 HttpServletResponse 中。在测试过程中，我们使用了 Mockito 的 verify 方法来验证方法的调用次数和参数是否正确。