我正在为我的spring Boot 应用程序编写junit测试用例，并且必须达到90%的代码覆盖率。我也想覆盖catch块的覆盖率，所以我尝试了DAO层方法的catch块的测试用例，但它没有按预期工作。
下面的代码是DAO层代码

public class GeneratorRepository {


    @Value("${existingQuery}")
    private String existingQuery;

    @Autowired
    private NamedParameterJdbcTemplate namedParameterJdbcTemplate;

    @Autowired
    private BeanPropertyRowMapper<Generator> generatorRowMapper;

    public Generator findExisting(Request request) {
        Generator ut = new Generator();
        try {
            SqlParameterSource namedParameters = new MapSqlParameterSource()
                    .addValue("no", request.getId(), Types.VARCHAR)
                    .addValue("trSu", request.getSu(), Types.VARCHAR)
                    .addValue("sta", request.getSta(), Types.VARCHAR);
            uti = namedParameterJdbcTemplate.queryForObject(existingQuery, namedParameters, generatorRowMapper);
        } catch (EmptyResultDataAccessException e) {
            uti = null;
        } catch (Exception e) {
            throw e;
        }
        return ut;
    }

}

我的测试用例这个测试用例它没有覆盖catch块。

@Test
    public void findExistingException() {
        Request request = new Request("12365", "QW" "qw");
        
        when(namedParameterJdbcTemplate.queryForObject(ArgumentMatchers.<String>any(), any(SqlParameterSource.class), eq(generatorRowMapper))).thenReturn(null);
        
        when(generatorRepo.findExisting(request)).thenThrow(new EmptyResultDataAccessException(1));
        EmptyResultDataAccessException exception = assertThrows(EmptyResultDataAccessException.class, () -> generatorRepo.findExisting(request));
    }