Question

请在下面找到我的示例代码。行映射器返回一个列表。打印时，它会给我DB中的大小，但是当我检查时

（List）employeeDaomap .get（＆＃34; allEmployees＆＃34;）我的列表大小为1，整行为一项？为什么实施中的错误

Spring doc也说不使用rs.next（），我们如何获取列表数据库中的值

public class MyTestDAO extends StoredProcedure {

/** The log. */
static Logger log = Logger.getLogger(MyTestDAO.class);
private static final String SPROC_NAME = "TestSchema.PKG_Test.prc_get_employee_list";
TestRowMapper mapper=new TestRowMapper();

public MyTestDAO(DataSource dataSource){
    super(dataSource, SPROC_NAME);
    declareParameter(new SqlOutParameter("allEmployees", OracleTypes.CURSOR, mapper));
    compile();
}

/**
 * Gets the myemplist data from the DB
 * 
 */
public  List<EmployeeDAO> getEmployeeList()
        throws Exception {

    Map<String,Object> employeeDaomap =new HashMap<String,Object>(); 
    employeeDaomap =execute();
    log.info("employeeDaomap after execute ="+employeeDaomap);
    log.info("employeeDaomap after execute size ="+employeeDaomap.size()); // expected 1
    List<EmployeeDAO> list = (List<EmployeeDAO>) employeeDaomap .get("allEmployees");
    log.info("size of the list ="+list.size()); // need to get the size of the list ,
    return list;
}


private Map<String, Object> execute() {
    return super.execute(new HashMap<String, Object>());
}
}

public class TestRowMapper implements RowMapper<List<EmployeeDAO>> {
static Logger log = Logger.getLogger(TestRowMapper.class);

@Override
public List<EmployeeDAO> mapRow(ResultSet rs, int rowNum)
        throws SQLException {
    // TODO Auto-generated method stub
    rs.setFetchSize(3000);
    List<EmployeeDAO> responseItems = new ArrayList<EmployeeDAO>();
    EmployeeDAO responseItem = null;
    log.info("row num "+rowNum);
    while (rs.next()) {

        responseItem = new EmployeeDAO();
        responseItem.setID(rs.getString("id"));
        responseItem.setName(rs.getString("name"));
        responseItem.setDesc(rs.getString("desc"));
        responseItems.add(responseItem);

    }
    log.info("TestRowMapper items ="+responseItems);
    return responseItems;
}
}

Answer 1

解决方案是使用implements ResultSetExtractor而不是RowMapper，并为extractData提供实现。

 




   public class TestRowMapper implements ResultSetExtractor<List<EmployeeDAO>> {
        static Logger log = Logger.getLogger(TestRowMapper.class);

    @Override
    public List<EMAccountResponse> extractData(ResultSet rs)
			throws SQLException, DataAccessException {
	    rs.setFetchSize(3000);
        List<EmployeeDAO> responseItems = new ArrayList<EmployeeDAO>();
        EmployeeDAO responseItem = null;
        log.info("row num "+rowNum);
        while (rs.next()) {

            responseItem = new EmployeeDAO();
            responseItem.setID(rs.getString("id"));
            responseItem.setName(rs.getString("name"));
            responseItem.setDesc(rs.getString("desc"));
            responseItems.add(responseItem);

         }
        log.info("TestRowMapper items ="+responseItems);
        return responseItems;
	 }
}

RowMapper返回列表，但执行返回值会将列表大小返回1吗？

1 个答案: