Java SQL查询执行，读取结果集行时出现问题

我正在编写简单的Java代码，我必须在我的Postgresql数据库上执行SQL查询。 这个数据库的结果（我手动检查过）是一个由一列和两个整数组成的简单表，如下所示：

我的问题是我找不到任何方法来阅读这两行。 我的阅读代码是：

_conn.setReadOnly（假）

_stmt=\u conn.createStatement（ResultSet.TYPE\u SCROLL\u SENSITIVE，ResultSet.CONCUR\u READ\u）

_stmt.setFetchSize（100）

Listlista=新列表（）

_rs=_stmt.executeQuery（查询）

而（_rs.next（））{

列表a.add（（短）rs.getInt（1））

}

此代码只读取第一行，但无法使其读取第二行。 短列表“lista”始终包含1个元素。 这就像如果结果集没有继续读取第二行

如何读取这两行

编辑：我尝试使用ArrayList，但不起作用。我已经为_conn连接和_stmt语句添加了代码部分。 问题是：

            SELECT COUNT(bffK.biological_function_feature_oid) 
        FROM biological_function_feature AS bff 
        INNER JOIN biological_function_feature_unfolded AS bffu 
        ON bff.biological_function_feature_oid = bffu.term_oid 
        INNER JOIN (    SELECT DISTINCT ON (g.gene_oid, bffu.ancestor_oid) g.gene_oid AS ance_gene, bffu.ancestor_oid AS ance_oid, mf.feature_name AS feature_name, mf.feature_id AS feature_id, ef.name AS evidence, qf.name AS qualifier  
                FROM gene2biological_function_feature AS g2bff  
                INNER JOIN biological_function_feature AS bff  
                ON g2bff.biological_function_feature_oid = bff.biological_function_feature_oid   
                INNER JOIN biological_function_feature_unfolded AS bffu  
                ON bffu.term_oid = bff.biological_function_feature_oid  
                INNER JOIN metadata.feature AS mf ON bff.feature_type = mf.feature_id   
                INNER JOIN gene AS g ON g2bff.gene_oid = g.gene_oid  
                LEFT JOIN flag.evidence_flags AS ef ON g2bff.evidence = ef.id  
                LEFT JOIN flag.qualifier_flags AS qf ON g2bff.qualifier = qf.id     
                LEFT JOIN flag.inferred_flags AS fif ON fif.id = g2bff.inferred    
                WHERE g.gene_oid=(4060969) 
                AND (bff.is_obsolete NOT IN ('t') OR bff.is_obsolete IS NULL)    
                AND (g.is_obsolete NOT IN ('t') OR g.is_obsolete IS NULL)
                AND distance=1   
                 UNION 
                SELECT DISTINCT ON (g.gene_oid, bff.biological_function_feature_oid)   
                g.gene_oid AS ance_gene, bff.biological_function_feature_oid AS ance_oid, 
                mf.feature_name AS feature_name, mf.feature_id AS feature_id,  
                ef.name AS evidence, 
                qf.name AS qualifier   
                FROM gene2biological_function_feature AS g2bff  
                INNER JOIN biological_function_feature AS bff  
                ON g2bff.biological_function_feature_oid = bff.biological_function_feature_oid    
                INNER JOIN metadata.feature AS mf ON bff.feature_type = mf.feature_id    
                INNER JOIN gene AS g ON g2bff.gene_oid = g.gene_oid  
                LEFT JOIN flag.evidence_flags AS ef ON g2bff.evidence = ef.id  
                LEFT JOIN flag.qualifier_flags AS qf ON g2bff.qualifier = qf.id     
                LEFT JOIN flag.inferred_flags AS fif ON fif.id = g2bff.inferred    
                WHERE g.gene_oid=(4060969) 
                AND (bff.is_obsolete NOT IN ('t') OR bff.is_obsolete IS NULL)   
                AND (g.is_obsolete NOT IN ('t') OR g.is_obsolete IS NULL)  
                AND ef.name NOT IN ('IEA', 'ND') 
            ) 
        AS unf ON unf.ance_oid = bffu.ancestor_oid 
        INNER JOIN gene AS gK on gk.Gene_oid=ance_gene 
        INNER JOIN biological_function_feature AS bffK 
        ON bffK.biological_function_feature_oid = bffu.ancestor_oid 
        LEFT JOIN flag.evidence_flags AS efK  
        ON evidence = efK.name 
        LEFT JOIN flag.qualifier_flags AS qfK  
        ON qualifier = qfK.name 
        WHERE bffu.distance=1 AND (bff.biological_function_feature_oid) IN (217538)
        AND evidence NOT IN ('IEA', 'ND')   
        UNION 
        SELECT COUNT(bffK.biological_function_feature_oid) 
        FROM biological_function_feature AS bff 
        INNER JOIN biological_function_feature_unfolded AS bffu 
        ON bff.biological_function_feature_oid = bffu.term_oid 
        INNER JOIN (    SELECT DISTINCT ON (g.gene_oid, bffu.ancestor_oid) g.gene_oid AS ance_gene, bffu.ancestor_oid AS ance_oid, mf.feature_name AS feature_name, mf.feature_id AS feature_id, ef.name AS evidence, qf.name AS qualifier  
                FROM gene2biological_function_feature AS g2bff  
                INNER JOIN biological_function_feature AS bff  
                ON g2bff.biological_function_feature_oid = bff.biological_function_feature_oid   
                INNER JOIN biological_function_feature_unfolded AS bffu  
                ON bffu.term_oid = bff.biological_function_feature_oid  
                INNER JOIN metadata.feature AS mf ON bff.feature_type = mf.feature_id   
                INNER JOIN gene AS g ON g2bff.gene_oid = g.gene_oid  
                LEFT JOIN flag.evidence_flags AS ef ON g2bff.evidence = ef.id  
                LEFT JOIN flag.qualifier_flags AS qf ON g2bff.qualifier = qf.id     
                LEFT JOIN flag.inferred_flags AS fif ON fif.id = g2bff.inferred    
                WHERE g.gene_oid=(4060969) 
                AND (bff.is_obsolete NOT IN ('t') OR bff.is_obsolete IS NULL)    
                AND (g.is_obsolete NOT IN ('t') OR g.is_obsolete IS NULL)
                AND distance=1   
                 UNION 
                SELECT DISTINCT ON (g.gene_oid, bff.biological_function_feature_oid)   
                g.gene_oid AS ance_gene, bff.biological_function_feature_oid AS ance_oid, 
                mf.feature_name AS feature_name, mf.feature_id AS feature_id,  
                ef.name AS evidence, 
                qf.name AS qualifier   
                FROM gene2biological_function_feature AS g2bff  
                INNER JOIN biological_function_feature AS bff  
                ON g2bff.biological_function_feature_oid = bff.biological_function_feature_oid    
                INNER JOIN metadata.feature AS mf ON bff.feature_type = mf.feature_id    
                INNER JOIN gene AS g ON g2bff.gene_oid = g.gene_oid  
                LEFT JOIN flag.evidence_flags AS ef ON g2bff.evidence = ef.id  
                LEFT JOIN flag.qualifier_flags AS qf ON g2bff.qualifier = qf.id     
                LEFT JOIN flag.inferred_flags AS fif ON fif.id = g2bff.inferred    
                WHERE g.gene_oid=(4060969) 
                AND (bff.is_obsolete NOT IN ('t') OR bff.is_obsolete IS NULL)   
                AND (g.is_obsolete NOT IN ('t') OR g.is_obsolete IS NULL)  
                AND ef.name IN ('IEA', 'ND') 
            ) 
        AS unf ON unf.ance_oid = bffu.ancestor_oid 
        INNER JOIN gene AS gK on gk.Gene_oid=ance_gene 
        INNER JOIN biological_function_feature AS bffK 
        ON bffK.biological_function_feature_oid = bffu.ancestor_oid 
        LEFT JOIN flag.evidence_flags AS efK  
        ON evidence = efK.name 
        LEFT JOIN flag.qualifier_flags AS qfK  
        ON qualifier = qfK.name 
        WHERE bffu.distance=1 AND (bff.biological_function_feature_oid) IN (217538)
        AND evidence IN ('IEA', 'ND')

---

这似乎与语法无关。在对数据库运行查询时，是否也会得到一行？也许您也可以发布SQL查询。

列表是一个界面，请尝试使用类似ArrayList的东西

List< Short > lista = new ArrayList< Short >();

_rs = _stmt.executeQuery(query);

     while (_rs.next()) {

lista.add((short)_rs.getShort(1));

}

Listlista=newarraylist（）；
_rs=_stmt.executeQuery（查询）；
而（_rs.next（））{
列表a.add（（short）rs.getShort（1））；
}

列表是一个接口，因此您不能直接实例化，而不是使用它的一个实现，如ArrayList。还要注意，count在PG中是一个关键字，所以避免使用关键字作为标识符。工作解决方案：

pst = connection.prepareStatement("SELECT * FROM demo");
List<Short> lista = new ArrayList<Short>();
rs = pst.executeQuery();

while (rs.next()) {
   lista.add((short)rs.getInt(1));
}

pst=connection.prepareStatement（“从演示中选择*）；
List lista=new ArrayList（）；
rs=pst.executeQuery（）；
while（rs.next（））{
添加（（短）rs.getInt（1））；
}

查询是什么样子的？大家好。我没有解决我的问题，但我更改了查询以获得两行两列作为输出，然后结果集工作正常。我改变了查询选择部分的方式：

SELECT COUNT（bffK.biological\u function\u feature\u oid），
SELECT COUNT（bffK.biological\u function\u feature\u oid），
SELECT COUNT（bfk.biological\u feature\u oid），[…]中的“非IEA非ND”。输出为：第一行“IEA ND”| 0；第二行：“非IEA非ND”1。无论如何，谢谢。我已经插入了关于连接和语句的查询和一些代码细节。也许他们是问题所在？这个问题对我来说太可怕了。这不是代码片段，这对我来说很有用。