java.sql.SQLException：在结果集开始之前
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java.sql.SQLException: Before start of result set
提问by GreatGatsby
I'm facing a problem getting data from my MySqldatabase. My code is the following:
我在从MySql数据库中获取数据时遇到问题。我的代码如下：
try {
Connection con = datasource.getConnection();
Statement stmt = con.createStatement();
ResultSet rs;
rs = stmt.executeQuery("SELECT tittle,date,path " +
"FROM announcement "+
"ORDER BY date");
String tittle=rs.getString("tittle");
String date=rs.getString("date");
String text=rs.getString("path");
if (!rs.isBeforeFirst())
{
out.println("<p>No data !</p>");
}
else
{
out.println("<table class=\"data\">");
out.println("<tr ><td class=\"sectionheader\"> tittle?</td><td class=\"sectionheader\">date</td><td class=\"sectionheader\">text</td></tr>");
while (rs.next()) {
String row="";
row += "<td><a href=\"\"> "+tittle+ "</td>";
row += "<td>" + date + "</td>";
row +="<td>"+text+"</td>";
row +="</tr>";
out.println(row);
}
The error I get is "java.sql.SQLException: Before start of result set"Any tip of what I am doing wrong?
我得到的错误是"java.sql.SQLException: Before start of result set"任何提示我做错了什么？
Thank you in advance.
先感谢您。
回答by RP-
You access the data in a ResultSet object through a cursor. Initially cursor points to before first row.
您可以通过游标访问 ResultSet 对象中的数据。最初光标指向第一行之前。
while(rs.next()) {
String tittle=rs.getString("tittle");
....
}
More to it, your query might return more than one row, in that case, you may want to store the results in a collection, List<Map<String, String>>, where each entry in the list represents one row from your query resutls and the map hold the column name vs column value.
更重要的是，您的查询可能返回不止一行，在这种情况下，您可能希望将结果存储在一个集合中List<Map<String, String>>，其中列表中的每个条目代表查询结果中的一行，而地图保存列名 vs列值。
