第二个sql语句得到的resultset对象是空的怎么办

Question

public ListgetAll1(String name) throws Exception {

Listresult = new ArrayList();

Connection con = DatabaseConnection.getConnection();

String na=null;

String sql1= "select * from guanzhu where guanzhu=?";

PreparedStatement ps1 = con.prepareStatement(sql1);

ps1.setString(1, name);

ResultSet rs1 = ps1.executeQuery();

while(rs1.next()){

Connection con1 = DatabaseConnection.getConnection();

na=rs1.getString("beiguanzhu");

String sql = "select * from message where author=? order by modified desc"; PreparedStatement ps = con1.prepareStatement(sql);

ps.setString(1, na); ResultSet rs = ps.executeQuery();

while (rs.next()) {

Message m = new Message();

m.setId(rs.getInt("id"));

m.setTitle(rs.getString("title"));

m.setContent(rs.getString("content"));

m.setModified(rs.getDate("modified"));

m.setAuthor(rs.getString("author"));

result.add(m);

System.out.println(rs.getString("author")+"");

}

}

return result;
}

Answer 1

断点一下，看看na等于多少，看看是不是一定没有数据，其实你可以写出来试下，先把第一个条件查出的Message集合放到一个临时的list里面，在用for循环查询下，这样试下也可以。