java.sql.SQLException：在开始结果集之前(java.sql.SQLException: Before start of result set)

java.sql.SQLException：在开始结果集之前(java.sql.SQLException: Before start of result set)

这里我附加了我的代码，它显示了如下错误：java.sql.SQLException：

在结果开始之前，我在这里做错了什么：

String qry = "SELECT * From register "; stmt = (PreparedStatement) conn.prepareStatement(qry); rs = stmt.executeQuery(); while (rs.next()) { String area = rs.getString("city"); if(city.equals(area)){ System.out.println("!!!!!!It matched: " + city); String qry2="select state from register where city='"+city+"'"; System.out.println(qry2); stmt = (PreparedStatement) conn.prepareStatement(qry2); rs = stmt.executeQuery(); String state=rs.getString("state"); System.out.println("state: " + state); break; } else { //System.out.println("No match with: " + area); } }

Here I have attached my code, it shows the error like: java.sql.SQLException:

Before start of result set what I am doing wrong here:

String qry = "SELECT * From register "; stmt = (PreparedStatement) conn.prepareStatement(qry); rs = stmt.executeQuery(); while (rs.next()) { String area = rs.getString("city"); if(city.equals(area)){ System.out.println("!!!!!!It matched: " + city); String qry2="select state from register where city='"+city+"'"; System.out.println(qry2); stmt = (PreparedStatement) conn.prepareStatement(qry2); rs = stmt.executeQuery(); String state=rs.getString("state"); System.out.println("state: " + state); break; } else { //System.out.println("No match with: " + area); } }

最满意答案

代码中不需要第二个结果集。 State和City都可以在同一结果集中找到。 您可以使用以下代码：

String qry = "select * from register"; PreparedStatement stmt = (PreparedStatement) conn.prepareStatement(qry); rs = stmt.executeQuery(); while (rs.next()) { String area = rs.getString("city"); if(city.equals(area)){ System.out.println("!!!!!!It matched: " + city); String state=rs.getString("state"); System.out.println("state: " + state); break; } else { //System.out.println("No match with: " + area); } }

Second resultset is not required in your code. State and City both can be found in same resultset. You can use the following code:

String qry = "select * from register"; PreparedStatement stmt = (PreparedStatement) conn.prepareStatement(qry); rs = stmt.executeQuery(); while (rs.next()) { String area = rs.getString("city"); if(city.equals(area)){ System.out.println("!!!!!!It matched: " + city); String state=rs.getString("state"); System.out.println("state: " + state); break; } else { //System.out.println("No match with: " + area); } }