@(Java)代码片段
import java.sql.*;
/**创建JDBC应用程序的步骤
* 1.载入JDBC驱动程序
* 2.定义连接URL
* 3.建立连接
* 4.创建Statement对象
* 5.执行查询或更新
* 6.结果处理
* 7.关闭连接
* Created by hp on /11/10.
*/
public class Main {
public static void main(String[] args){
String driver = "oracle.jdbc.driver.OracleDriver";
//2、定义连接URL
String url = "jdbc:oracle:thin:@localhost:1521:orcl";
String username = "scott";//用户名
String password = "tiger";//密码
String sql = "select empno, ename from emp";
Connection connection;
Statement statement;
ResultSet resultSet;
try {
//1、加载驱动Oracle的jdbc驱动包
Class.forName(driver);
//3、建立连接 ：制定连接到哪里去jdbc:oracle:thin: ip地址 : 端口号 :
connection = DriverManager.getConnection(url, username, password);
//4、创建statement对象，便于执行静态sql语句
statement = connection.createStatement();
/*动态执行SQL语句
String updateSql = "update Users set name = ? where id = ?";
PreparedStatement ps= connection.prepareStatement(updateSql);
ps.setString(1, "王五");//设置第一个“？”的值
ps.setInt(2, 1);//设置第二个“？”的值
statement.executeUpdate(insertSql);
*/
//5、执行查询或更新操作
resultSet = statement.executeQuery(sql);
//6、结果处理 方式一
while (resultSet.next()){
int empno = resultSet.getInt("empno");
String ename = resultSet.getString("ename");
System.out.println(empno+" "+ename);
}
//6、结果处理 方式二：比较通用，对于结果集有多列时，有好处
//获取结果集的列数
int columnCount = resultSet.getMetaData().getColumnCount();
for (int i = 0; i < columnCount; i++) {
Object o = resultSet.getObject(i+1);
System.out.print(o);
//System.out.printf("%15s", o);//格式化输出
if (i!=columnCount-1){
System.out.print(",");
}
}
System.out.println();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
finally {
//7、关闭连接
try {
if (resultSet != null) {
resultSet.close();
}
if (statement != null) {
statement.close();
}
if (connection != null) {
connection.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
