▲▲▲百分求救:关于JAVA与MYSQL,来者有分,绝不失言▲▲▲
MYSQL中有一个库mydb,其下有一张表usercode
mysql> desc usercode;
+--------------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------------+-------------+------+-----+---------+-------+
| USERID | varchar(8) | NO | PRI | | |
| USERNAME | varchar(20) | YES | | NULL | |
+--------------+-------------+------+-----+---------+-------+
在JAVA中执行如下语句
……
String sql="select userid ,username,now() as time from usercode where userid='wb' ";
ResultSet rs = statement.executeQuery(sql);
//获得数据结果集合
ResultSetMetaData rmeta = rs.getMetaData();
//确定数据集的列数,亦字段数
int numColumns=rmeta.getColumnCount();
System.out.println(numColumns);
for(int i=1;i<=numColumns;i++)
{
System.out.print(rmeta.getColumnName(i));
System.out.print("|");
}
System.out.print("\n");
while(rs.next()) {
for(int j=1;j<=numColumns;j++)
{
System.out.print(rs.getString(j)+" ");
System.out.print("|");
}
}
……
结果如下:
USERID|USERNAME||
wb |卫斌 |2006-06-09 16:27:16.0 |
数据库操作成功,恭喜你Press any key to continue...
大家看看表头
USERID|USERNAME||
我希望得到的表头是
USERID|USERNAME|TIME|
为什么会是这样子的,请大家查一下原因。
附录:以下为本实验的全部源代码,供大家帮我解决问题时使用
------DBBean.java-----------------
import java.sql.*;
import java.lang.*;
public class DBBean
{
public static void main(String args[ ])
{
try
{
//驱动程序名
String driverName="com.mysql.jdbc.Driver";
//数据库用户名
String userName="root";
//密码
String userPasswd="123";
//数据库名
String dbName="mydb";
//表名
String tableName="usercode";
//联结字符串
String url="jdbc:mysql://localhost/"+dbName+"?user="+userName+"&password="+userPasswd+"&useUnicode=true&characterEncoding=gb2312";
System.out.println(url);
Class.forName("com.mysql.jdbc.Driver").newInstance();
Connection connection=DriverManager.getConnection(url);
java.sql.Statement statement = connection.createStatement();
String sql="select userid ,username,now() as time from usercode where userid='wb' ";
ResultSet rs = statement.executeQuery(sql);
//获得数据结果集合
ResultSetMetaData rmeta = rs.getMetaData();
//确定数据集的列数,亦字段数
int numColumns=rmeta.getColumnCount();
System.out.println(numColumns);
for(int i=1;i<=numColumns;i++)
{
System.out.print(rmeta.getColumnName(i));
System.out.print("|");
}
System.out.print("\n");
while(rs.next()) {
for(int j=1;j<=numColumns;j++)
{
System.out.print(rs.getString(j)+" ");
System.out.print("|");
}
}
System.out.print("\n");
System.out.print("数据库操作成功,恭喜你");
rs.close();
statement.close();
connection.close();
}
catch(Exception e)
{
System.out.println(e.toString());
}
}
}