求一个java数据库访问函数的写法!大侠们指点 String sql= "select isUse from user where isUse=1 and userid=?if(rs.next())result = true;else result = false这样行吗 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 楼上的办法还不是要用rs.next()来判断是否存在符合要求的记录吗?楼主说了,只有一条记录,那你的一次循环就不用了只要if(rs.next()){ if(rs.getString(1).equals("1")) result = true; else result = false; } String sql= "select isUse from user where isUse=1 and userid=?" rs = db.query(sql, args);if(rs.next())result = true;else result = false 这是一个用jdbc-odbc桥接器连接access数据库world20.mdb的一个例子, 在连接数据源时命名为WorldEnergy所以下面才有Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");import java.sql.*; public class CoalTotals { public static void main(String[] arguments) { String data = "jdbc:odbc:WorldEnergy"; try { Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); Connection conn = DriverManager.getConnection( data, "", ""); Statement st = conn.createStatement(); ResultSet rec = st.executeQuery( "SELECT * " + "FROM Coal " + "WHERE " + "(Country='" + arguments[0] + "') " + "ORDER BY Year"); System.out.println("FIPS\tCOUNTRY\t\tYEAR\t" + "ANTHRACITE PRODUCTION"); while(rec.next()) { System.out.println(rec.getString(1) + "\t" + rec.getString(2) + "\t\t" + rec.getString(3) + "\t" + rec.getString(4)); } st.close(); } catch (SQLException s) { System.out.println("SQL Error: " + s.toString() + " " + s.getErrorCode() + " " + s.getSQLState()); } catch (Exception e) { System.out.println("Error: " + e.toString() + e.getMessage()); } }}还有什么问题可以给我发信息噢!! java_web User is not mapped urlrewrite下载 想学习Java的SSH框架,但是存在很多疑惑,希望各位指点迷津 关于java EE service层的使用 java可不可以定义返回值是只读的? 求一解决方案!我被郁闷了! 如何使用java获得当前TCP/IP连接的网络流量??请各位高手指教! 怎样获得容器上下文Context 这种嵌套的json如何用easyui的combobox处理呢? Struts的数据库权限管理? 哪里有J2EE SDK!
楼主说了,只有一条记录,那你的一次循环就不用了
只要
if(rs.next()){
if(rs.getString(1).equals("1")) result = true;
else result = false;
}
rs = db.query(sql, args);
if(rs.next())result = true;
else result = false
public class CoalTotals {
public static void main(String[] arguments) {
String data = "jdbc:odbc:WorldEnergy";
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection conn = DriverManager.getConnection(
data, "", "");
Statement st = conn.createStatement();
ResultSet rec = st.executeQuery(
"SELECT * " +
"FROM Coal " +
"WHERE " +
"(Country='" + arguments[0] + "') " +
"ORDER BY Year");
System.out.println("FIPS\tCOUNTRY\t\tYEAR\t" +
"ANTHRACITE PRODUCTION");
while(rec.next()) {
System.out.println(rec.getString(1) + "\t"
+ rec.getString(2) + "\t\t"
+ rec.getString(3) + "\t"
+ rec.getString(4));
}
st.close();
} catch (SQLException s) {
System.out.println("SQL Error: " + s.toString() + " "
+ s.getErrorCode() + " " + s.getSQLState());
} catch (Exception e) {
System.out.println("Error: " + e.toString()
+ e.getMessage());
}
}
}
还有什么问题可以给我发信息噢!!