请问这样为什么通不过？

[shijies]

Statement stat = conn.createStatement();
ResultSet rs = stat.executeQuery("SELECT * FROM Greetings");
while (rs.next()) {
System.out.println(rs.getString(1));
}

编译后出现：

Exception in thread "main" java.lang.Error: Unresolved compilation problem:
conn cannot be resolved

at pkg.Main.main(Main.java:32)

[weixin_39670158]

没取到conn哦

[方元之外]

如果没记错 rs.getString(1) 里面放的应该是字符串类型的字段名。 表的字段名

[shijies]

用以下代码可以连接上数据库： package pkg; import java.sql.*; public class Main { public static void main(String [] args) { String driverName="com.microsoft.sqlserver.jdbc.SQLServerDriver"; String dbURL="jdbc:sqlserver://localhost:1433;DatabaseName=lianyu"; String userName="sa"; String userPwd="shijie"; try { Class.forName(driverName); Connection dbConn=DriverManager.getConnection(dbURL,userName,userPwd); System.out.println("连接数据库成功"); } catch(Exception e) { e.printStackTrace(); System.out.print("连接失败"); } } } 但是往里面加上以下代码就不行了 Statement stat = conn.createStatement(); ResultSet rs = stat.executeQuery("SELECT * FROM Greetings"); while (rs.next()) { System.out.println(rs.getString(1)); }

[huawangxin]

引用 3 楼 shijies 的回复:

用以下代码可以连接上数据库： package pkg; import java.sql.*; public class Main { public static void main(String [] args) { String driverName="com.microsoft.sqlserver.jdbc.SQLServerDriver"; String dbURL="jdbc:sqlserver://localhost:1433;DatabaseName=lianyu"; String userName="sa"; String userPwd="shijie"; try { Class.forName(driverName); Connection dbConn=DriverManager.getConnection(dbURL,userName,userPwd); System.out.println("连接数据库成功"); } catch(Exception e) { e.printStackTrace(); System.out.print("连接失败"); } } } 但是往里面加上以下代码就不行了 Statement stat = conn.createStatement(); ResultSet rs = stat.executeQuery("SELECT * FROM Greetings"); while (rs.next()) { System.out.println(rs.getString(1)); }

这样写就可以了