JDBCPagingItemReader将结果返回为NULL

Question

我在尝试使用spring-batch从数据库中获取数据时遇到问题。 我能够正确传递数据源，也测试了连接。但是当我实施spring-batch时。我总是在结果中得到NULL。这是我的读者课程。请支持。

Public class Database {

Logger log = LogManager.getLogger(Database.class.getName());

@Bean
public ItemReader<ReservedMSISDNVo> databaseCsvItemReader(DataSource dataSource) throws Exception {
    JdbcPagingItemReader<ReservedMSISDNVo> databaseReader = new JdbcPagingItemReader<ReservedMSISDNVo>();

    databaseReader.setDataSource(dataSource);
    databaseReader.setPageSize(1);

    PagingQueryProvider queryProvider = createQueryProvider(dataSource);
    databaseReader.setQueryProvider(queryProvider);
    databaseReader.setFetchSize(2);
    databaseReader.setRowMapper(new ParameterizedRowMapper<ReservedMSISDNVo>() {
        public ReservedMSISDNVo mapRow(ResultSet rs, int rowNum)
                throws SQLException {
            ReservedMSISDNVo reservedMSISDNVo = new ReservedMSISDNVo();
            reservedMSISDNVo.setMSISDN(rs.getString("MOBILE"));
            return reservedMSISDNVo;
        }
    });


    return databaseReader;
}

private PagingQueryProvider createQueryProvider(DataSource dataSource) throws Exception {
    H2PagingQueryProvider queryProvider = new H2PagingQueryProvider();
    String latestDateQuery = "SELECT SNQ_DATE FROM SNQ_POSTPAID"; 
    queryProvider.setSelectClause("select MOBILE");
    queryProvider.setFromClause("from NUMBERS_POSTPAID");
    queryProvider.setWhereClause("");
    queryProvider.setSortKeys(sortByMSISDN());
    queryProvider.init(dataSource);
   /* Date latestDate = jdbcTemplateObject.queryForObject(latestDateQuery,
            new Object[] {}, Date.class);
    if (latestDate != null) {
        queryProvider.setWhereClause("WHERE RESERVED = 'true' AND INSERT_DATE="+latestDate);
    }else{
        queryProvider.setWhereClause("WHERE RESERVED = 'true'");
    }*/
    return queryProvider;
}

private Map<String, Order> sortByMSISDN() {
    Map<String, Order> sortConfiguration = new HashMap<>();
    sortConfiguration.put("MOBILE", Order.ASCENDING);
    return sortConfiguration;
}

}