以下是使用“结果集”教程中描述的几种导航方法的示例。
该示例代码是根据前几章中的环境和数据库设置编写的。
复制并粘贴以下示例到JDBCExample.java中，如下编译并运行：
//步骤1.导入所需的软件包
import java.sql.*;
public class JDBCExample {
// JDBC驱动程序名称和数据库URL
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://localhost/EMP";
// 数据库凭证
static final String USER = "username";
static final String PASS = "password";
public static void main(String[] args) {
Connection conn = null;
Statement stmt = null;
try{
//步骤2：注册JDBC驱动程序
Class.forName("com.mysql.jdbc.Driver");
//步骤3：建立连接
System.out.println("Connecting to database...");
conn = DriverManager.getConnection(DB_URL,USER,PASS);
//步骤4：执行查询以创建陈述
// RS示例的必需参数。
System.out.println("Creating statement...");
stmt = conn.createStatement(
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
String sql;
sql = "SELECT id, first, last, age FROM Employees";
ResultSet rs = stmt.executeQuery(sql);
// 将光标移到最后一行。
System.out.println("Moving cursor to the last...");
rs.last();
//步骤5：从结果集中提取数据
System.out.println("Displaying record...");
//按列名检索
int id = rs.getInt("id");
int age = rs.getInt("age");
String first = rs.getString("first");
String last = rs.getString("last");
//显示值
System.out.print("ID: " + id);
System.out.print(", Age: " + age);
System.out.print(", First: " + first);
System.out.println(", Last: " + last);
// 将光标移到第一行。
System.out.println("Moving cursor to the first row...");
rs.first();
//步骤6：从结果集中提取数据
System.out.println("Displaying record...");
//按列名检索
id = rs.getInt("id");
age = rs.getInt("age");
first = rs.getString("first");
last = rs.getString("last");
//显示值
System.out.print("ID: " + id);
System.out.print(", Age: " + age);
System.out.print(", First: " + first);
System.out.println(", Last: " + last);
// 将光标移到第一行。
System.out.println("Moving cursor to the next row...");
rs.next();
//步骤7：从结果集中提取数据
System.out.println("Displaying record...");
id = rs.getInt("id");
age = rs.getInt("age");
first = rs.getString("first");
last = rs.getString("last");
//显示值
System.out.print("ID: " + id);
System.out.print(", Age: " + age);
System.out.print(", First: " + first);
System.out.println(", Last: " + last);
//步骤8：清理环境
rs.close();
stmt.close();
conn.close();
}catch(SQLException se){
//处理JDBC错误
se.printStackTrace();
}catch(Exception e){
//处理Class.forName的错误
e.printStackTrace();
}finally{
//用于关闭资源
try{
if(stmt!=null)
stmt.close();
}catch(SQLException se2){
}
try{
if(conn!=null)
conn.close();
}catch(SQLException se){
se.printStackTrace();
}
}
System.out.println("Goodbye!");
}
}//结束JDBCExample现在让我们编译上面的示例，如下所示：
C:\>javac JDBCExample.java C:\>
运行时JDBCExample，它将产生以下结果-
C:\>java JDBCExample Connecting to database... Creating statement... Moving cursor to the last... Displaying record... ID: 103, Age: 30, First: Sumit, Last: Mittal Moving cursor to the first row... Displaying record... ID: 100, Age: 18, First: Zara, Last: Ali Moving cursor to the next row... Displaying record... ID: 101, Age: 25, First: Mahnaz, Last: Fatma Goodbye! C:\>